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Associations of trimester-specific gestational weight gain with maternal adiposity and systolic blood pressure at 3 and 7 years postpartum

Published:November 13, 2014DOI:https://doi.org/10.1016/j.ajog.2014.11.012

      Objective

      Our objective was to examine the associations of total and trimester-specific gestational weight gain (GWG) rate with postpartum maternal weight and cardiometabolic risk. We hypothesized that first-trimester GWG would be most strongly associated with long-term maternal health.

      Study Design

      We studied 801 women enrolled during the first trimester of pregnancy in the Boston-area Project Viva cohort 1999 through 2002. At 3 years postpartum we measured maternal weight, waist circumference (WC), and systolic blood pressure (SBP) and collected fasting blood from a subset. At 7 years postpartum we again measured weight and WC. We used multivariable linear regression to evaluate relations of total and trimester-specific GWG rate with weight change (vs self-reported prepregnancy weight) and WC at each time point, stratified by prepregnancy weight, as well as associations with SBP and insulin resistance at 3 years.

      Results

      Median age at enrollment was 34.0 years (range, 16.4–44.9); 65% were white. Mean (SD) total GWG rate was 0.38 (0.14) kg/wk. Women gained weight faster during the second (0.47 [0.19] kg/wk) and third (0.44 [0.22] kg/wk) trimesters than the first (0.22 [0.22] kg/wk). Total and first-trimester GWG rate were most strongly associated with postpartum weight change. Among normal-weight women, each 1-SD increase in total and first-trimester GWG rate corresponded with 0.85 (95% confidence interval [CI], 0.07–1.63) kg and 2.08 (1.32–2.84) kg greater weight change at 3 and 7 years postpartum, respectively, but there was not strong evidence of association for either second- (–0.30 kg; 95% CI, –1.08 to 0.48) or third- (–0.26 kg; 95% CI, –1.08 to 0.55) trimester GWG. First-trimester GWG rate also related to 3-year postpartum weight change in overweight (2.28 kg; 95% CI, 0.95–3.61) and obese (2.47 kg; 95% CI, 0.98–3.97) women. Greater total and first-trimester GWG rate were associated with larger WC and higher SBP but not insulin resistance.

      Conclusion

      In this observational cohort, first-trimester weight gain was more strongly associated with maternal weight retention as well as higher WC and blood pressure than second- or third-trimester gain. Interventions targeting GWG beginning very early in pregnancy may benefit long-term maternal health.

      Key words

      An estimated 40% of normal-weight women and 60% of overweight women exceed Institute of Medicine (IOM) recommendations for gestational weight gain (GWG).
      • Chu S.Y.
      • Callaghan W.M.
      • Bish C.L.
      • D'Angelo D.
      Gestational weight gain by body mass index among US women delivering live births, 2004-2005: fueling future obesity.
      Excess GWG is associated with greater short-term postpartum weight retention and adverse cardiometabolic outcomes for both mother and child, including increased risk of obesity, central adiposity, and higher systolic blood pressure (SBP).
      • Rooney B.L.
      • Schauberger C.W.
      • Mathiason M.A.
      Impact of perinatal weight change on long-term obesity and obesity-related illnesses.
      • Mamun A.A.
      • Kinarivala M.
      • O'Callaghan M.J.
      • Williams G.M.
      • Najman J.M.
      • Callaway L.K.
      Associations of excess weight gain during pregnancy with long-term maternal overweight and obesity: evidence from 21 y postpartum follow-up.
      • Amorim A.R.
      • Rossner S.
      • Neovius M.
      • Lourenco P.M.
      • Linne Y.
      Does excess pregnancy weight gain constitute a major risk for increasing long-term BMI?.
      • Fraser A.
      • Tilling K.
      • Macdonald-Wallis C.
      • et al.
      Associations of gestational weight gain with maternal body mass index, waist circumference, and blood pressure measured 16 y after pregnancy: the Avon longitudinal study of parents and children (ALSPAC).
      • McClure C.K.
      • Catov J.M.
      • Ness R.
      • Bodnar L.M.
      Associations between gestational weight gain and BMI, abdominal adiposity, and traditional measures of cardiometabolic risk in mothers 8 y postpartum.
      • Fraser A.
      • Tilling K.
      • Macdonald-Wallis C.
      • et al.
      Association of maternal weight gain in pregnancy with offspring obesity and metabolic and vascular traits in childhood.
      • Oken E.
      • Taveras E.M.
      • Kleinman K.P.
      • Rich-Edwards J.W.
      • Gillman M.W.
      Gestational weight gain and child adiposity at age 3 years.
      Clinicians and researchers typically focus on total GWG.
      American Congress of Obstetricians and Gynecologists
      Obesity in pregnancy. ACOG Committee opinion no. 549.
      However, weight gained across specific intervals of pregnancy has differential contributions to maternal, placental, and fetal growth. Greater early GWG is associated with higher risk of pregnancy complications, including hypertensive disorders of pregnancy,
      • Macdonald-Wallis C.
      • Tilling K.
      • Fraser A.
      • Nelson S.M.
      • Lawlor D.A.
      Gestational weight gain as a risk factor for hypertensive disorders of pregnancy.
      gestational diabetes,
      • Morisset A.S.
      • Tchernof A.
      • Dube M.C.
      • Veillette J.
      • Weisnagel S.J.
      • Robitaille J.
      Weight gain measures in women with gestational diabetes mellitus.
      • Carreno C.A.
      • Clifton R.G.
      • Hauth J.C.
      • et al.
      Excessive early gestational weight gain and risk of gestational diabetes mellitus in nulliparous women.
      and postpartum weight retention,
      • Muscati S.K.
      • Gray-Donald K.
      • Koski K.G.
      Timing of weight gain during pregnancy: promoting fetal growth and minimizing maternal weight retention.
      independent of body mass index (BMI) entering pregnancy. To our knowledge only 1 study has examined GWG timing with respect to longer-term maternal outcomes.
      • Fraser A.
      • Tilling K.
      • Macdonald-Wallis C.
      • et al.
      Associations of gestational weight gain with maternal body mass index, waist circumference, and blood pressure measured 16 y after pregnancy: the Avon longitudinal study of parents and children (ALSPAC).
      In that analysis, midpregnancy GWG (19-28 weeks) was more strongly related to adiposity and blood pressure at 16 years postpartum, but only among normal-weight women.
      • Fraser A.
      • Tilling K.
      • Macdonald-Wallis C.
      • et al.
      Associations of gestational weight gain with maternal body mass index, waist circumference, and blood pressure measured 16 y after pregnancy: the Avon longitudinal study of parents and children (ALSPAC).
      However, in that United Kingdom cohort recruited 1991 through 1992, both maternal BMI (mean, 22.5 kg/m2) and GWG (mean, 12.6 kg) were substantially lower than is common in the United States today, and obese women were not studied separately. Categorizing by prepregnancy BMI is both practically important given that current IOM guidelines
      stratify by prepregnancy weight status, and physiologically important given known differences in gestational metabolism between normal-weight and obese women.
      • Lain K.Y.
      • Catalano P.M.
      Metabolic changes in pregnancy.
      In this study, we hypothesized that first-trimester GWG would be most strongly associated with long-term maternal cardiometabolic health measures, including overall and central adiposity, SBP, and insulin resistance at 3 and 7 years postpartum.

      Materials and Methods

      Study population

      We studied participants from Project Viva, a prospective prebirth cohort of women enrolled 1999 through 2002 from Harvard Vanguard Medical Associates, a multispecialty practice in eastern Massachusetts.
      • Oken E.
      • Baccarelli A.
      • Gold D.
      • Kleinman K.
      • Litonjua A.
      • De Meo E.
      Cohort profile: Project Viva.
      All women provided written informed consent at each visit and the Harvard Pilgrim Health Care Institutional Review Board approved this study.
      Of 2128 mothers who delivered a live singleton infant, we conducted in-person visits with 1287 at 3 years postpartum (median, 3.2; range, 2.8–6.2 years) and 1107 at 7 years postpartum (median, 7.7; range, 6.6–10.9 years). We excluded from this analysis women who were underweight entering pregnancy (BMI <18.5 kg/m2) because of insufficient sample size for stratified analysis, or who had an intervening pregnancy after the index delivery, which might affect outcomes, which left 741 eligible participants in the 3-year analysis and 525 women in the 7-year analysis. The 801 women total (some women were included at both visits) were similar to those excluded although the analyzed cohort was slightly older (mean age 34 vs 31 years), had higher prepregnancy BMI (∼1.2 kg/m2), and accordingly gained less total weight during pregnancy (0.9 kg).

      Exposure: total and trimester-specific GWG rate

      Women reported their prepregnancy weight at study enrollment. We obtained serial clinical weights from prenatal records, with a median of 13 (3-28) repeated measurements per woman. We calculated total GWG rate as the difference between the last clinically measured weight (within 4 weeks prior to delivery) and self-reported prepregnancy weight divided by gestation length in weeks. Since literature varies for specific periods of GWG,
      • Fraser A.
      • Tilling K.
      • Macdonald-Wallis C.
      • et al.
      Associations of gestational weight gain with maternal body mass index, waist circumference, and blood pressure measured 16 y after pregnancy: the Avon longitudinal study of parents and children (ALSPAC).
      • Kleinman K.P.
      • Oken E.
      • Radesky J.S.
      • Rich-Edwards J.W.
      • Peterson K.E.
      • Gillman M.W.
      How should gestational weight gain be assessed? A comparison of existing methods and a novel method, area under the weight gain curve.
      we took a data-driven approach to identify population-specific cutoff points that demarcate significant differences in GWG rate throughout pregnancy. Using methods described by Fraser et al,
      • Fraser A.
      • Tilling K.
      • Macdonald-Wallis C.
      • et al.
      Associations of gestational weight gain with maternal body mass index, waist circumference, and blood pressure measured 16 y after pregnancy: the Avon longitudinal study of parents and children (ALSPAC).
      we identified linear slope changes at 15 and 28 weeks’ gestational age. However, these time points were not substantially superior to those used for trimester cutoffs, so we proceeded with more clinically relevant trimesters. We defined first trimester as the date of last menstrual period to day 91, second trimester as day 91-182, and third trimester as day 182 to the date of delivery. We performed linear interpolation between the 2 closest weight measures to estimate weight at day 91 and day 182 and calculated trimester-specific GWG rates (kg/wk) for each period.

      Postpartum health outcomes

      During in-person 3-year postpartum visits, trained research assistants measured women’s weight to the nearest 0.1 kg using an electronic scale (model 881; Seca Corp, Hanover, MD); waist circumference (WC) to the nearest 1 mm using a nonstretchable measuring tape; and SBP 5 times, 1 minute apart, with a Dinamap Pro 100 (Critikon Inc, Tampa, FL). Phlebotomists collected blood specimens, which were processed within 24 hours. We assayed glucose and insulin from plasma only from women who were fasting at least 12 hours at the time of the visit (n = 181); we did not require that all women attend the visit in a fasted state. We used the homeostasis model assessment (HOMA) to estimate insulin resistance from these samples: HOMA-IR = (fasting insulin [μU/mL] × fasting glucose [mmol/L]/22.5). At the 7-year visit, research assistants again measured weight (scale model TBF-300A; Tanita Corp of America Inc, Arlington Heights, IL) and WC, but not blood pressure and did not collect blood, as we did not have funding at this visit to assess maternal outcomes. We calculated postpartum weight change as the difference between weight at each time point (3 or 7 years postpartum) and prepregnancy weight.

      Assessment of covariates

      At enrollment and the midpregnancy visit, women completed questionnaires and interviews inquiring about race, ethnicity, education, parity, and lifestyle characteristics including smoking habits, diet, and physical activity.
      • Oken E.
      • Baccarelli A.
      • Gold D.
      • Kleinman K.
      • Litonjua A.
      • De Meo E.
      Cohort profile: Project Viva.
      We calculated prepregnancy BMI using self-reported prepregnancy weight and height. Medical records provided prenatal glucose tolerance status,
      • Regnault N.
      • Gillman M.W.
      • Rifas-Shiman S.L.
      • Eggleston E.
      • Oken E.
      Sex-specific associations of gestational glucose tolerance with childhood body composition.
      delivery date, and infant sex. Mothers reported breast-feeding duration in postpartum questionnaires.

      Data analysis

      First, in bivariate analyses, we evaluated the distributions of total weight gain rate and gain in each trimester across categories of sociodemographic, anthropometric, perinatal, and lifestyle characteristics to identify potential confounders of the association of GWG rate with postpartum outcomes. We assessed their significance using the Wald χ2 test for categorical variables and a test for linear trend for ordinal variables.
      Next, we examined the relations of total and trimester-specific weight gain rate with change in weight and WC by 3 and 7 years postpartum using multivariable linear regression models. We conducted separate analyses for normal-weight (BMI 18.5–24.9 kg/m2), overweight (BMI 25.0–29.9 kg/m2), and obese (BMI ≥30 kg/m2) women in light of evidence of an interaction (P-interaction < .05) between prepregnancy weight status and GWG rate for the anthropometric outcomes. We quantified the difference and 95% confidence interval in each postpartum outcome according to quintiles of total and trimester-specific GWG rate. Because the associations were generally linear and monotonic, we opted to examine GWG rate continuously, scaled to a 1-SD increment to optimize power. In our base model (model 1), we accounted for confounders including age, race, education, prepregnancy BMI, parity, and partner’s BMI. We adjusted for GWG rate in the previous period(s) when second- or third-trimester GWG rate was the exposure of interest. Unadjusted results are not presented since they were not notably different from base model results. We then additionally adjusted for pregnancy smoking habits, gestational glucose tolerance, child’s sex, and breast-feeding duration (model 2). Covariate selection was based on bivariate associations and a priori knowledge of GWG predictors. All models met assumptions for linear regression.
      For cardiometabolic outcomes (SBP and HOMA-IR) at 3 years postpartum, we examined associations among all women because associations did not differ by prepregnancy weight status (P-interaction > .10 for all models). We accounted for the same set of covariates as described above for models 1 and 2, but we also included a third model (model 3) that accounted for current adiposity (BMI at 3 years postpartum). In models for HOMA-IR, we excluded women with type 1 and type 2 diabetes, or gestational diabetes mellitus, which can influence both patterns of weight gain
      • Morisset A.S.
      • Tchernof A.
      • Dube M.C.
      • Veillette J.
      • Weisnagel S.J.
      • Robitaille J.
      Weight gain measures in women with gestational diabetes mellitus.
      and postpartum hyperglycemia.
      • Hanna F.W.
      • Peters J.R.
      Screening for gestational diabetes; past, present and future.
      • Bellamy L.
      • Casas J.P.
      • Hingorani A.D.
      • Williams D.
      Type 2 diabetes mellitus after gestational diabetes: a systematic review and meta-analysis.
      Adjustment for physical activity before pregnancy, and adherence to the prudent or Western dietary patterns
      • Radesky J.S.
      • Oken E.
      • Rifas-Shiman S.L.
      • Kleinman K.P.
      • Rich-Edwards J.W.
      • Gillman M.W.
      Diet during early pregnancy and development of gestational diabetes.
      during early pregnancy did not change results so they were not included in the final models. We conducted sensitivity analyses excluding preterm births (gestational age <37 weeks; n = 56) and women with preeclampsia (n = 26) and observed no substantial differences in our findings.
      Some subjects were missing covariate information (Appendix; Supplemental Table 1), so we used chained equations in SAS PROC MI to impute values for these covariates.
      • White I.
      • Royston P.
      • Wood A.
      Multiple imputation using chained equations: issues and guidance for practice.
      To avoid incorrect imputations, all Project Viva subjects were used in generating imputed values. We generated 50 imputed datasets and our reported results combine the estimates across the results.
      • Rubin D.
      Multiple imputation for nonresponse in surveys.
      We included only participants with observed, nonimputed outcomes. The results from analyses using imputed data were not materially different from those using original data (data not shown). All analyses were performed using software (SAS, version 9.3; SAS Institute Inc, Cary, NC).

      Results

      Median age at enrollment was 34.0 years (range, 16.4–44.9) and 65.4% of women were white. Mean (SD) total GWG was 15.0 (5.6) kg over 39.4 (1.9) weeks’ gestation, or an average gain of 0.38 (0.14) kg/wk throughout pregnancy. Women gained weight at faster rates during the second (6.1 [2.5] kg at 0.47 [0.19] kg/wk) and third (6.0 [2.9] kg at 0.44 [0.22] kg/wk) trimesters than in the first (2.9 [2.9] kg at 0.22 [0.22] kg/wk). The mean rate of GWG for normal, overweight, and obese women in the cohort exceeded 2009 IOM recommendations
      for the second and third trimesters (Table 1).
      Table 1Rates of total and trimester-specific gestational weight gain
      VariableObserved in Project VivaIOM guidelines,
      Values are adapted from IOM 2009 recommendations.14
      MeanRangeRange
      Total GWG rate, kg/wk
       Normal weight (BMI 18.5–24.9)0.390.08 to 0.780.28–0.40
       Overweight (BMI 25–29.9)0.400.06 to 0.860.17–0.28
       Obese (BMI ≥30)0.30−0.19 to 0.760.12–0.23
      First-trimester GWG rate, kg/wk
       Normal weight (BMI 18.5–24.9)0.22−0.67 to 1.080.04–0.15
       Overweight (BMI 25–29.9)0.24−0.69 to 1.200.04–0.15
       Obese (BMI ≥30)0.21−0.63 to 1.220.04–0.15
      Second-trimester GWG rate, kg/wk
       Normal weight (BMI 18.5–24.9)0.510.04 to 1.060.36–0.45
       Overweight (BMI 25–29.9)0.500.01 to 1.200.23–0.32
       Obese (BMI ≥30)0.31−0.41 to 0.970.18–0.27
      Third-trimester GWG rate, kg/wk
       Normal weight (BMI 18.5–24.9)0.45−0.24 to 0.980.36–0.45
       Overweight (BMI 25–29.9)0.46−0.34 to 1.150.23–0.32
       Obese (BMI ≥30)0.39−0.45 to 1.000.18–0.27
      BMI, body mass index; GWG, gestational weight gain; IOM, Institute of Medicine.
      Walter. Trimester-specific weight gain and maternal health. Am J Obstet Gynecol 2015.
      a Values are adapted from IOM 2009 recommendations.
      Associations of GWG rate with sociodemographic and behavioral characteristics differed by trimester (Table 2). Second- and third-trimester GWG rate varied with many sociodemographic characteristics including maternal age (third trimester), marital status and race/ethnicity (second trimester), and education and household income (both). In contrast, first-trimester GWG rate did not vary with these characteristics, but was associated with behaviors including smoking, prepregnancy physical activity, and diet pattern. GWG rate varied across prepregnancy BMI categories for second- and third-trimester gain, but not for first-trimester gain.
      Table 2Rates of gestational weight gain according to maternal characteristics
      VariableMean ± SD rate of GWG, kg/wk
      n (%)TotalFirst trimesterSecond trimesterThird trimester
      (0-13 wk)(14-26 wk)(≥27 wk)
      Overall8010.38 ± 0.140.22 ± 0.220.47 ± 0.190.44 ± 0.22
      SOCIODEMOGRAPHIC CHARACTERISTICS
      Age at enrollment, y
       15-2461 (8)0.40 ± 0.160.20 ± 0.310.48 ± 0.220.50 ± 0.25
       25-34403 (50)0.38 ± 0.150.22 ± 0.240.47 ± 0.210.45 ± 0.22
       35-44337 (42)0.37 ± 0.130.23 ± 0.190.47 ± 0.180.42 ± 0.21
      P value trend
      From test for linear trend in which ordinal predictor is entered into model as continuous variable
      .25.36.83.003
      Marital status
       Married/cohabitating725 (91)0.38 ± 0.140.22 ± 0.220.47 ± 0.190.44 ± 0.22
       Single76 (9)0.37 ± 0.170.24 ± 0.270.41 ± 0.250.45 ± 0.25
      P value
      From Wald χ2 test.
      .39.60.01.82
      Race/ethnicity
       Black142 (18)0.36 ± 0.150.23 ± 0.290.42 ± 0.230.42 ± 0.24
       Hispanic65 (8)0.36 ± 0.160.23 ± 0.290.44 ± 0.210.40 ± 0.26
       White524 (65)0.39 ± 0.140.22 ± 0.190.48 ± 0.190.46 ± 0.21
       Asian35 (4)0.36 ± 0.090.20 ± 0.170.45 ± 0.110.45 ± 0.21
       Other35 (4)0.41 ± 0.160.27 ± 0.330.49 ± 0.180.47 ± 0.22
      P value
      From Wald χ2 test.
      .11.53.01.13
      Annual household income
       <$20,00051 (6)0.37 ± 0.180.23 ± 0.370.43 ± 0.250.44 ± 0.27
       $20,000–39,99992 (11)0.35 ± 0.180.23 ± 0.310.42 ± 0.240.39 ± 0.26
       $40,000–69,999180 (22)0.37 ± 0.160.22 ± 0.270.45 ± 0.240.45 ± 0.24
       $70,000–100,000173 (22)0.37 ± 0.140.22 ± 0.190.48 ± 0.200.41 ± 0.23
       >$100,000306 (38)0.40 ± 0.120.23 ± 0.190.49 ± 0.170.48 ± 0.20
      P value trend
      From test for linear trend in which ordinal predictor is entered into model as continuous variable
      .003.87.0003.02
      Education
       Primary75 (9)0.35 ± 0.150.22 ± 0.290.43 ± 0.230.40 ± 0.21
       Secondary486 (61)0.38 ± 0.150.22 ± 0.230.47 ± 0.210.44 ± 0.24
       University240 (30)0.39 ± 0.120.22 ± 0.180.48 ± 0.160.46 ± 0.19
      P value trend
      From test for linear trend in which ordinal predictor is entered into model as continuous variable
      .08.89.05.05
      Smoking habits
       Never558 (70)0.38 ± 0.140.22 ± 0.220.47 ± 0.180.44 ± 0.21
       Quit before pregnancy155 (19)0.38 ± 0.140.22 ± 0.210.47 ± 0.210.45 ± 0.24
       Smoked in early pregnancy88 (11)0.40 ± 0.160.28 ± 0.260.46 ± 0.230.45 ± 0.24
      P value
      From Wald χ2 test.
      .64.02.92.81
      Partner's BMI, kg/m2
       Not overweight (<25 kg/m2)283 (35)0.39 ± 0.130.23 ± 0.210.48 ± 0.190.45 ± 0.22
       Overweight (≥25 kg/m2)518 (65)0.38 ± 0.150.22 ± 0.240.46 ± 0.200.44 ± 0.23
      P value
      From Wald χ2 test.
      .39.79.14.91
      PERINATAL CHARACTERISTICS
      Prepregnancy BMI, kg/m2
       Normal (18.5–24.9 kg/m2)454 (57)0.39 ± 0.110.22 ± 0.180.51 ± 0.150.45 ± 0.19
       Overweight (25.0–29.9 kg/m2)195 (24)0.40 ± 0.140.24 ± 0.240.50 ± 0.190.46 ± 0.24
       Obese (≥30.0 kg/m2)152 (19)0.30 ± 0.190.21 ± 0.310.31 ± 0.250.39 ± 0.28
      P value trend
      From test for linear trend in which ordinal predictor is entered into model as continuous variable
      < .0001.91< .0001.01
      Parity
       0234 (29)0.39 ± 0.140.23 ± 0.210.48 ± 0.200.47 ± 0.22
       1368 (46)0.38 ± 0.140.22 ± 0.230.46 ± 0.190.45 ± 0.21
       ≥2199 (25)0.37 ± 0.140.23 ± 0.240.47 ± 0.200.41 ± 0.23
      P value trend
      From test for linear trend in which ordinal predictor is entered into model as continuous variable
      .10.86.71.001
      Gestational glucose tolerance
       Normoglycemic648 (81)0.39 ± 0.140.22 ± 0.220.48 ± 0.190.46 ± 0.20
       Isolated hyperglycemia82 (10)0.35 ± 0.150.21 ± 0.230.44 ± 0.200.40 ± 0.24
       Impaired glucose tolerance32 (4)0.40 ± 0.160.30 ± 0.270.48 ± 0.240.41 ± 0.27
       Gestational diabetes39 (5)0.31 ± 0.160.25 ± 0.250.39 ± 0.220.29 ± 0.34
      P value trend
      From test for linear trend in which ordinal predictor is entered into model as continuous variable
      .003.20.02< .0001
      Offspring sex
       Male412 (51)0.39 ± 0.140.23 ± 0.230.48 ± 0.200.46 ± 0.23
       Female389 (49)0.37 ± 0.140.22 ± 0.220.46 ± 0.190.43 ± 0.21
      P value
      From Wald χ2 test.
      .02.36.12.05
      Prudent dietary pattern
       Q1 (lowest)199 (25)0.38 ± 0.150.20 ± 0.270.47 ± 0.200.46 ± 0.23
       Q2201 (25)0.37 ± 0.150.20 ± 0.210.47 ± 0.220.44 ± 0.22
       Q3200 (25)0.38 ± 0.150.22 ± 0.210.47 ± 0.200.45 ± 0.24
       Q4 (highest)201 (25)0.39 ± 0.150.28 ± 0.250.47 ± 0.190.43 ± 0.24
      P value trend
      From test for linear trend in which ordinal predictor is entered into model as continuous variable
      .19.001.72.21
      Prepregnancy physical activity
       Q1 (lowest)169 (21)0.35 ± 0.150.18 ± 0.250.44 ± 0.210.43 ± 0.22
       Q2178 (22)0.40 ± 0.130.23 ± 0.230.49 ± 0.200.48 ± 0.21
       Q3244 (30)0.39 ± 0.140.24 ± 0.210.47 ± 0.200.45 ± 0.23
       Q4 (highest)210 (26)0.38 ± 0.160.24 ± 0.260.48 ± 0.210.42 ± 0.25
      P value trend
      From test for linear trend in which ordinal predictor is entered into model as continuous variable
      .12.01.19.47
      BMI, body mass index; GWG, gestational weight gain.
      Walter. Trimester-specific weight gain and maternal health. Am J Obstet Gynecol 2015.
      a From test for linear trend in which ordinal predictor is entered into model as continuous variable
      b From Wald χ2 test.
      In adjusted regression models, the rate of first-trimester GWG was more strongly associated with postpartum weight change and WC than rate of gain in either of the other 2 trimesters, regardless of prepregnancy weight status (Figure). Results for second- and third-trimester gain were similar even without adjustment for weight gain in the previous period(s) (data not shown). Associations of total GWG rate with both weight change and WC followed similar trends to those of the first trimester, more so than the second and third trimesters at both 3 and 7 years postpartum (Figure). Additional adjustment for smoking, gestational glucose tolerance, offspring sex, and breast-feeding duration did not attenuate associations (Supplemental Tables 2 and 3).
      Figure thumbnail gr1
      FigureAssociations of GWG rates with postpartum weight change and waist circumference
      All associations are adjusted for mother's age, parity, race, education, prepregnancy body mass index (BMI), and partner's BMI (model 1). Estimates for second- and third-trimester gestational weight gain (GWG) are also adjusted for GWG rate from previous trimester(s).
      Walter. Trimester-specific weight gain and maternal health. Am J Obstet Gynecol 2015.
      For normal-weight women entering pregnancy, each 1-SD increment in first-trimester GWG rate (0.22 kg/wk) corresponded with 2.08 (95% confidence interval, 1.32–2.84) kg greater weight change from prepregnancy to 3 years postpartum. Associations were null for both second-trimester gain (−0.30; −1.08 to 0.48 per 0.19 kg/wk) and third-trimester gain (−0.26; −1.08 to 0.55 per 0.22 kg/wk). Patterns were similar for WC, such that normal-weight women had 1.70 (0.96—2.44) cm greater WC for each 1-SD increase in first trimester GWG rate, compared to 0.16 (−0.60 to 0.92) cm per 19 kg/wk and 0.82 (−0.03 to 1.62) per 0.22 kg/wk for second- and third-trimester gains, respectively. Similarly, first-trimester GWG rate was most strongly associated with both weight change and WC at 3 years postpartum among overweight and obese women (Supplemental Table 3).
      The differences in associations of early GWG with maternal outcomes among normal, overweight, and obese became more apparent at 7 years postpartum. Among normal-weight women, GWG in all trimesters was associated with weight change and WC, although the relation was strongest for first-trimester rate of gain (Supplemental Tables 2 and 3). In overweight women only first-trimester gain was associated with weight change, but in obese women, second-trimester GWG was most strongly associated.
      After accounting for confounders, first-trimester GWG was directly related to SBP (1.48 [0.69-2.27] mm Hg per 0.22 kg/wk), but not second- or third-trimester GWG (Table 3). The association between total GWG and SBP (0.93 [0.10-1.76] mm Hg per 0.14 kg/wk) persisted after accounting for potential mediating characteristics during the peripartum period (Table 3) (model 2), but was attenuated to null after accounting for BMI at 3 years, whereas first-trimester GWG remained associated with 3-year postpartum SBP in all models. Neither total nor trimester-specific GWG rate was related to HOMA-IR at 3 years postpartum among the smaller subset of women who provided fasting blood samples.
      Table 3Associations of gestational weight gain with cardiometabolic outcomes
      VariableDifference (95% CI)
      Per 1 SD total GWG rate
      1 SD = 0.14 kg/wk
      Per 1 SD first-trimester GWG rate
      1 SD = 0.22 kg/wk
      Per 1 SD second-trimester GWG rate
      1 SD = 0.19 kg/wk
      Per 1 SD third-trimester GWG rate
      1 SD = 0.22 kg/wk
      SBP, mm Hg
       (n = 741)Model 10.93 (0.10–1.76)1.48 (0.69–2.27)0.04 (−0.81 to 0.90)−0.08 (−1.01 to 0.84)
      Model 21.00 (0.16–1.84)1.49 (0.69–2.30)0.09 (−0.77 to 0.94)−0.01 (−0.95 to 0.93)
      Model 30.69 (−0.17 to 1.54)1.14 (0.31–1.97)0.02 (−0.84 to 0.87)−0.07 (−1.00 to 0.86)
      HOMA–IR
      Natural-log transformed HOMA-IR due to nonnormal distributions–participants with gestational, type 1, or type 2 diabetes were excluded from HOMA-IR results.
       (n = 167)Model 1−0.03 (−0.14 to 0.07)−0.04 (−0.14 to 0.06)0.02 (−0.09 to 0.13)−0.06 (−0.18 to 0.06)
      Model 2−0.01 (−0.11 to 0.10)−0.03 (−0.13 to 0.08)0.03 (−0.08 to 0.14)−0.04 (−0.17 to 0.09)
      Model 3−0.03 (−0.14 to 0.08)−0.06 (−0.16 to 0.05)0.02 (−0.09 to 0.13)−0.04 (−0.16 to 0.09)
      Model 1: Adjusted for age, race/ethnicity, parity, education, prepregnancy body mass index, and partner's body mass index; estimates for second- and third-trimester GWG are also adjusted for GWG rate from previous trimester(s).
      Model 2: Model 1 + smoking habits during pregnancy, gestational glucose tolerance, offspring sex, and breast-feeding duration.
      Model 3: Model 2 + body mass index at 3 y.
      CI, confidence interval; GWG, gestational weight gain; SBP, systolic blood pressure.
      Walter. Trimester-specific weight gain and maternal health. Am J Obstet Gynecol 2015.
      a 1 SD = 0.14 kg/wk
      b 1 SD = 0.22 kg/wk
      c 1 SD = 0.19 kg/wk
      d 1 SD = 0.22 kg/wk
      e Natural-log transformed HOMA-IR due to nonnormal distributions–participants with gestational, type 1, or type 2 diabetes were excluded from HOMA-IR results.
      Among 343 Project Viva mothers who had weight recorded in the medical record in the 3 months before their last menstrual period, mean underreporting of self-reported prepregnancy weight was ∼1 kg, but the correlation between self-reported and clinically measured weight was very high (r = 0.997) and underreporting was nondifferential with respect to prepregnancy BMI, gestational age at enrollment, and race/ethnicity. We evaluated the potential impact of underreporting prepregnancy weight by examining the relations of first-trimester weight gain with outcomes after adding 1 kg to the self-reported values. Using the corrected values attenuated the magnitude of associations by about one-third, but did not change the overall trends or significance of first-trimester or total GWG rate (data not shown).

      Comment

      Our finding that first-trimester weight gain was most strongly associated with postpartum maternal cardiometabolic outcomes has a likely mechanistic explanation, as weight gain early in pregnancy primarily represents maternal fat deposition rather than fetal or placental tissue or fluid gain.
      • Morisset A.S.
      • Tchernof A.
      • Dube M.C.
      • Veillette J.
      • Weisnagel S.J.
      • Robitaille J.
      Weight gain measures in women with gestational diabetes mellitus.
      • van Raaij J.M.
      • Peek M.E.
      • Vermaat-Miedema S.H.
      • Schonk C.M.
      • Hautvast J.G.
      New equations for estimating body fat mass in pregnancy from body density or total body water.
      • Hedderson M.M.
      • Gunderson E.P.
      • Ferrara A.
      Gestational weight gain and risk of gestational diabetes mellitus.
      Excess fat has been hypothesized to predispose women to perinatal insulin resistance, and this risk may extend to the postpartum period.
      • Hedderson M.M.
      • Gunderson E.P.
      • Ferrara A.
      Gestational weight gain and risk of gestational diabetes mellitus.
      While other studies have shown that excess early GWG is independently associated with greater postpartum weight retention in women as early as 6 weeks after delivery,
      • Fraser A.
      • Tilling K.
      • Macdonald-Wallis C.
      • et al.
      Associations of gestational weight gain with maternal body mass index, waist circumference, and blood pressure measured 16 y after pregnancy: the Avon longitudinal study of parents and children (ALSPAC).
      • Muscati S.K.
      • Gray-Donald K.
      • Koski K.G.
      Timing of weight gain during pregnancy: promoting fetal growth and minimizing maternal weight retention.
      our findings demonstrate these relationships persist for at least 7 years.
      The direct relationship between first-trimester GWG and postpartum weight retention was strongest among normal-weight women by 7 years postpartum, whereas at 3 years postpartum the association was strongest among obese women. Fraser et al
      • Fraser A.
      • Tilling K.
      • Macdonald-Wallis C.
      • et al.
      Associations of gestational weight gain with maternal body mass index, waist circumference, and blood pressure measured 16 y after pregnancy: the Avon longitudinal study of parents and children (ALSPAC).
      observed that greater midpregnancy GWG (19-28 weeks) was associated with higher central adiposity and blood pressure among normal-weight women at 16 years postpartum. The consistent observation between our results and the study of Fraser et al
      • Fraser A.
      • Tilling K.
      • Macdonald-Wallis C.
      • et al.
      Associations of gestational weight gain with maternal body mass index, waist circumference, and blood pressure measured 16 y after pregnancy: the Avon longitudinal study of parents and children (ALSPAC).
      that normal-weight women are most sensitive to higher GWG has a physiological basis. In early pregnancy, there is an increase in insulin sensitivity facilitating greater lipogenesis and fat storage in anticipation of future placental and fetal needs.
      • Lain K.Y.
      • Catalano P.M.
      Metabolic changes in pregnancy.
      Normal-weight women often experience a larger increase in fat stores during pregnancy than obese women, who are already more insulin resistant at baseline.
      • Lain K.Y.
      • Catalano P.M.
      Metabolic changes in pregnancy.
      • Ehrenberg H.M.
      • Huston-Presley L.
      • Catalano P.M.
      The influence of obesity and gestational diabetes mellitus on accretion and the distribution of adipose tissue in pregnancy.
      Therefore, normal-weight women are at the greatest risk to accumulate fat with excess early GWG. Furthermore, the weight that obese women gain is more likely fluid and nonfat tissue, which may be easier to lose following delivery.
      • Chu S.Y.
      • Callaghan W.M.
      • Bish C.L.
      • D'Angelo D.
      Gestational weight gain by body mass index among US women delivering live births, 2004-2005: fueling future obesity.
      • Kac G.
      • Benicio M.H.
      • Velasquez-Melendez G.
      • Valente J.G.
      Nine months postpartum weight retention predictors for Brazilian women.
      • Lederman S.A.
      • Paxton A.
      • Heymsfield S.B.
      • Wang J.
      • Thornton J.
      • Pierson Jr., R.N.
      Body fat and water changes during pregnancy in women with different body weight and weight gain.
      We also found that a greater first-trimester GWG rate was related to higher SBP at 3 years postpartum. While this finding is supported by the Avon Longitudinal Study of Parents and Children data,
      • Fraser A.
      • Tilling K.
      • Macdonald-Wallis C.
      • et al.
      Associations of gestational weight gain with maternal body mass index, waist circumference, and blood pressure measured 16 y after pregnancy: the Avon longitudinal study of parents and children (ALSPAC).
      another study of 478 women from Pittsburgh, PA, reported no association between total GWG and SBP at 8 years postpartum,
      • McClure C.K.
      • Catov J.M.
      • Ness R.
      • Bodnar L.M.
      Associations between gestational weight gain and BMI, abdominal adiposity, and traditional measures of cardiometabolic risk in mothers 8 y postpartum.
      perhaps because total GWG incorporates both early GWG, which was directly related to SBP, as well as later GWG, which was not. In our study, GWG rate was not related to HOMA-IR, perhaps because of the relatively short postpartum follow-up period that may fail to capture the natural time course of developing insulin resistance, or the smaller sample size for this outcome.
      Interestingly, sociodemographic characteristics were not associated with first-trimester GWG. Instead, the rate of early GWG was only related to maternal behaviors such as smoking, greater prepregnancy physical activity, and prudent diet. Although smoking status is a widely recognized contributor to metabolic dysfunction, our results regarding prepregnancy physical activity and diet are counterintuitive: adherence to a prudent diet and greater prepregnancy physical activity were associated with greater early GWG rate. It may be that women who exercise more and eat a healthier diet are also more insulin sensitive, leading to easier weight gain. Nevertheless, our results broadly suggest early GWG is more strongly influenced by modifiable behaviors rather than immutable characteristics, raising the possibility that interventions commencing before or very early in pregnancy might be more successful in influencing early GWG and thereby have a long-lasting impact on maternal health.
      In this study of reproductive-aged women with prospectively collected information on perinatal characteristics, research-quality measures of anthropometry and cardiometabolic biomarkers at 3 and 7 years postpartum, and rich data on potential confounders and mediators, we found differential associations of trimester-specific weight gain rate with long-term maternal health. Specifically, higher rates of weight gain during the first trimester were consistently related to greater maternal adiposity and higher SBP, whereas weight gain in the other trimesters was not associated with these postpartum outcomes.
      This study has several limitations. First, prepregnancy BMI was based on self-reported weight and may suffer reporting bias. However, self-reported and clinically measured prepregnancy weights were highly correlated and the magnitude of underreporting was not associated with key characteristics, including prepregnancy weight status. Any remaining bias is likely nondifferential. Also, our sensitivity analysis adding 1 kg to prepregnancy weight showed similar results. Second, we cannot rule out the possibility that GWG rate, especially during the first trimester, is driven by weight gain patterns and fat distribution prior to pregnancy. Third, as with all cohort studies, attrition bias may be an issue. In this study, many baseline characteristics were similar between participants included in the study and those lost to follow-up. Fourth, we restricted the sample to women without intervening pregnancies who, in addition to being older, may be inherently different from their counterparts in immeasurable ways; thus, limiting generalizability of our findings to all reproductive-aged women. Finally, we were unable to examine associations in underweight women due to insufficient sample size, and numbers with the HOMA-IR outcome were small, limiting power for those models.
      In conclusion, greater rate of GWG during early pregnancy corresponded with greater postpartum weight change, WC, and SBP. While additional work is required to evaluate the potential impact of moderating early GWG on long-term health, including child health, our findings suggest a potential role for targeted interventions that emphasize healthy weight gain in early pregnancy.

      Appendix

      Supplemental Table 1Number missing for key covariates
      Covariaten missing
      Age at enrollment0
      Parity0
      Race/ethnicity5
      Education level4
      Prepregnancy BMI0
      Partner's BMI36
      Offspring sex0
      Smoking habits during pregnancy2
      Gestational glucose tolerance16
      Breast-feeding duration70
      BMI, body mass index.
      Walter. Trimester-specific weight gain and maternal health. Am J Obstet Gynecol 2015.
      Supplemental Table 2Associations of total and trimester-specific rate of GWG with postpartum weight change, stratified by prepregnancy weight status
      VariableDifference (95% CI) in postpartum weight change, kg
      Per 1 SD total GWG rate
      1 SD = 0.14 kg/wk
      Per 1 SD first-trimester GWG rate
      1 SD = 0.22 kg/wk
      Per 1 SD second-trimester GWG rate
      1 SD = 0.19 kg/wk
      Per 1 SD third-trimester GWG rate
      1 SD = 0.22 kg/wk.
      Weight change from prepregnancy to 3 y postpartum
       Normal weightModel 10.85 (0.07–1.63)2.08 (1.32–2.84)−0.30 (−1.08 to 0.48)−0.26 (−1.08 to 0.55)
       (n = 429)Model 20.95 (0.19–1.72)2.19 (1.45–2.93)−0.16 (−0.91 to 0.60)−0.34 (−1.103 to 0.45)
       OverweightModel 12.28 (0.78–3.77)2.28 (0.95–3.61)0.73 (−0.83 to 2.28)0.82 (−0.74 to 2.38)
       (n = 181)Model 21.92 (0.39–3.45)2.22 (0.89–3.55)0.42 (−1.15 to 1.98)0.51 (−1.10 to 2.13)
       ObeseModel 12.48 (0.87–4.08)2.47 (0.98–3.97)0.86 (−0.85 to 2.56)0.97 (−0.96 to 2.90)
       (n = 131)Model 22.54 (0.84–4.23)2.58 (0.91–4.24)0.89 (−0.88 to 2.65)1.11 (−0.98 to 3.19)
      Weight change from prepregnancy to 7 y postpartum
       Normal weightModel 12.50 (1.67–3.32)2.40 (1.63–3.17)0.88 (0.05–1.70)1.06 (0.18–1.95)
       (n = 295)Model 22.50 (1.68–3.32)2.33 (1.56–3.09)0.89 (0.08–1.70)1.13 (0.24–2.02)
       OverweightModel 11.30 (−0.18 to 2.79)1.57 (0.27–2.88)−0.16 (−1.57 to 1.26)0.70 (−0.71 to 2.11)
       (n = 130)Model 21.27 (−0.27 to 2.81)1.69 (0.41–2.98)−0.18 (−1.59 to 1.24)0.47 (−1.02 to 1.97)
       ObeseModel 11.37 (−0.16 to 2.91)1.14 (−0.34 to 2.61)1.97 (0.16–3.78)−0.79 (−2.58 to 0.99)
       (n = 100)Model 21.30 (−0.29 to 2.89)1.04 (−0.59 to 2.66)1.94 (0.13–3.75)−0.80 (−2.67 to 1.07)
      Model 1: Adjusted for mother's age, parity, race, education, prepregnancy body mass index, and partner's body mass index; estimates for second- and third-trimester GWG are also adjusted for GWG rate from previous trimester(s). Model 2: Model 1 + smoking habits during pregnancy, gestational glucose tolerance, child's sex, and breast-feeding duration.
      CI, confidence interval; GWG, gestational weight gain.
      Walter. Trimester-specific weight gain and maternal health. Am J Obstet Gynecol 2015.
      a 1 SD = 0.14 kg/wk
      b 1 SD = 0.22 kg/wk
      c 1 SD = 0.19 kg/wk
      d 1 SD = 0.22 kg/wk.
      Supplemental Table 3Associations of total and trimester-specific rate of GWG with waist circumference at 3 and 7 years postpartum, stratified by prepregnancy weight status
      VariableDifference (95% CI) in waist circumference, cm
      Per 1 SD total GWG rate
      1 SD = 0.14 kg/wk
      Per 1 SD first-trimester GWG rate
      1 SD = 0.22 kg/wk
      Per 1 SD second-trimester GWG rate
      1 SD = 0.19 kg/wk
      Per 1 SD third-trimester GWG rate
      1 SD = 0.22 kg/wk.
      At 3 y postpartum
       Normal weightModel 11.46 (0.71–2.20)1.70 (0.96–2.44)0.16 (−0.60 to 0.92)0.82 (0.03–1.62)
       (n = 429)Model 21.47 (0.71–2.23)1.71 (0.96–2.46)0.19 (−0.57 to 0.95)0.81 (0.01–1.61)
       OverweightModel 10.77 (−0.42 to 1.96)2.17 (1.17–3.17)−0.59 (−1.80 to 0.62)−0.33 (−1.51 to 0.86)
       (n = 181)Model 21.05 (−0.15 to 2.24)2.26 (1.27–3.24)−0.57 (−1.77 to 0.62)−0.02 (−1.23 to 1.18)
       ObeseModel 12.08 (0.74–3.41)2.25 (1.01–3.49)0.28 (−1.14 to 1.69)1.22 (−0.38 to 2.81)
       (n = 131)Model 21.88 (0.51–3.24)1.70 (0.34–3.05)0.43 (−1.01 to 1.87)1.56 (−0.12 to 3.23)
      At 7 y postpartum
       Normal weightModel 12.24 (1.11–3.36)1.87 (0.82–2.92)0.28 (−0.87 to 1.44)1.99 (0.77–3.21)
       (n = 295)Model 22.21 (1.08–3.35)1.72 (0.66–2.78)0.30 (−0.85 to 1.45)2.11 (0.88–3.34)
       OverweightModel 1−0.38 (−2.07 to 1.32)1.28 (−0.20 to 2.76)−0.93 (−2.53 to 0.67)−0.78 (−2.38 to 0.81)
       (n = 130)Model 20.02 (−1.70 to 1.74)1.57 (0.13–3.01)−0.68 (−2.26 to 0.89)−0.81 (−2.47 to 0.85)
       ObeseModel 11.87 (0.27–3.47)1.80 (0.27–3.34)1.59 (−0.30 to 3.49)−0.30 (−2.18 to 1.58)
       (n = 100)Model 21.66 (0.09–3.23)1.19 (−0.43 to 2.82)1.67 (−0.13 to 3.47)0.18 (−1.69 to 2.05)
      Model 1: Adjusted for mother's age, parity, race, education, prepregnancy body mass index, and partner's body mass index; estimates for second- and third-trimester GWG are also adjusted for GWG rate from previous trimester(s). Model 2: Model 1 + smoking habits during pregnancy, gestational glucose tolerance, child's sex, and breast-feeding duration.
      CI, confidence interval; GWG, gestational weight gain.
      Walter. Trimester-specific weight gain and maternal health. Am J Obstet Gynecol 2015.
      a 1 SD = 0.14 kg/wk
      b 1 SD = 0.22 kg/wk
      c 1 SD = 0.19 kg/wk
      d 1 SD = 0.22 kg/wk.

      References

        • Chu S.Y.
        • Callaghan W.M.
        • Bish C.L.
        • D'Angelo D.
        Gestational weight gain by body mass index among US women delivering live births, 2004-2005: fueling future obesity.
        Am J Obstet Gynecol. 2009; 200: 271.e1-271.e7
        • Rooney B.L.
        • Schauberger C.W.
        • Mathiason M.A.
        Impact of perinatal weight change on long-term obesity and obesity-related illnesses.
        Obstet Gynecol. 2005; 106: 1349-1356
        • Mamun A.A.
        • Kinarivala M.
        • O'Callaghan M.J.
        • Williams G.M.
        • Najman J.M.
        • Callaway L.K.
        Associations of excess weight gain during pregnancy with long-term maternal overweight and obesity: evidence from 21 y postpartum follow-up.
        Am J Clin Nutr. 2010; 91: 1336-1341
        • Amorim A.R.
        • Rossner S.
        • Neovius M.
        • Lourenco P.M.
        • Linne Y.
        Does excess pregnancy weight gain constitute a major risk for increasing long-term BMI?.
        Obesity (Silver Spring). 2007; 15: 1278-1286
        • Fraser A.
        • Tilling K.
        • Macdonald-Wallis C.
        • et al.
        Associations of gestational weight gain with maternal body mass index, waist circumference, and blood pressure measured 16 y after pregnancy: the Avon longitudinal study of parents and children (ALSPAC).
        Am J Clin Nutr. 2011; 93: 1285-1292
        • McClure C.K.
        • Catov J.M.
        • Ness R.
        • Bodnar L.M.
        Associations between gestational weight gain and BMI, abdominal adiposity, and traditional measures of cardiometabolic risk in mothers 8 y postpartum.
        Am J Clin Nutr. 2013; 98: 1218-1225
        • Fraser A.
        • Tilling K.
        • Macdonald-Wallis C.
        • et al.
        Association of maternal weight gain in pregnancy with offspring obesity and metabolic and vascular traits in childhood.
        Circulation. 2010; 121: 2557-2564
        • Oken E.
        • Taveras E.M.
        • Kleinman K.P.
        • Rich-Edwards J.W.
        • Gillman M.W.
        Gestational weight gain and child adiposity at age 3 years.
        Am J Obstet Gynecol. 2007; 196: 322.e1-322.e8
        • American Congress of Obstetricians and Gynecologists
        Obesity in pregnancy. ACOG Committee opinion no. 549.
        Obstet Gynecol. 2013; 121: 213-217
        • Macdonald-Wallis C.
        • Tilling K.
        • Fraser A.
        • Nelson S.M.
        • Lawlor D.A.
        Gestational weight gain as a risk factor for hypertensive disorders of pregnancy.
        Am J Obstet Gynecol. 2013; 209: 327.e1-327.e17
        • Morisset A.S.
        • Tchernof A.
        • Dube M.C.
        • Veillette J.
        • Weisnagel S.J.
        • Robitaille J.
        Weight gain measures in women with gestational diabetes mellitus.
        J Womens Health (Larchmt). 2011; 20: 375-380
        • Carreno C.A.
        • Clifton R.G.
        • Hauth J.C.
        • et al.
        Excessive early gestational weight gain and risk of gestational diabetes mellitus in nulliparous women.
        Obstet Gynecol. 2012; 119: 1227-1233
        • Muscati S.K.
        • Gray-Donald K.
        • Koski K.G.
        Timing of weight gain during pregnancy: promoting fetal growth and minimizing maternal weight retention.
        Int J Obes Relat Metab Disord. 1996; 20: 526-532
      1. Rasmussen K.M. Yaktine A.L. Weight gain during pregnancy: reexamining the guidelines. The National Academies Press, Washington, DC2009
        • Lain K.Y.
        • Catalano P.M.
        Metabolic changes in pregnancy.
        Clin Obstet Gynecol. 2007; 50: 938-948
        • Oken E.
        • Baccarelli A.
        • Gold D.
        • Kleinman K.
        • Litonjua A.
        • De Meo E.
        Cohort profile: Project Viva.
        Int J Epidemiol. 2014 Mar 16; ([Epub ahead of print])
        • Kleinman K.P.
        • Oken E.
        • Radesky J.S.
        • Rich-Edwards J.W.
        • Peterson K.E.
        • Gillman M.W.
        How should gestational weight gain be assessed? A comparison of existing methods and a novel method, area under the weight gain curve.
        Int J Epidemiol. 2007; 36: 1275-1282
        • Regnault N.
        • Gillman M.W.
        • Rifas-Shiman S.L.
        • Eggleston E.
        • Oken E.
        Sex-specific associations of gestational glucose tolerance with childhood body composition.
        Diabetes Care. 2013; 36: 3045-3053
        • Hanna F.W.
        • Peters J.R.
        Screening for gestational diabetes; past, present and future.
        Diabet Med. 2002; 19: 351-358
        • Bellamy L.
        • Casas J.P.
        • Hingorani A.D.
        • Williams D.
        Type 2 diabetes mellitus after gestational diabetes: a systematic review and meta-analysis.
        Lancet. 2009; 373: 1773-1779
        • Radesky J.S.
        • Oken E.
        • Rifas-Shiman S.L.
        • Kleinman K.P.
        • Rich-Edwards J.W.
        • Gillman M.W.
        Diet during early pregnancy and development of gestational diabetes.
        Paediatr Perinat Epidemiol. 2008; 22: 47-59
        • White I.
        • Royston P.
        • Wood A.
        Multiple imputation using chained equations: issues and guidance for practice.
        Stat Med. 2011; 30: 377-399
        • Rubin D.
        Multiple imputation for nonresponse in surveys.
        Wiley-Interscience, Hoboken, NJ2004
        • van Raaij J.M.
        • Peek M.E.
        • Vermaat-Miedema S.H.
        • Schonk C.M.
        • Hautvast J.G.
        New equations for estimating body fat mass in pregnancy from body density or total body water.
        Am J Clin Nutr. 1988; 48: 24-29
        • Hedderson M.M.
        • Gunderson E.P.
        • Ferrara A.
        Gestational weight gain and risk of gestational diabetes mellitus.
        Obstet Gynecol. 2010; 115: 597-604
        • Ehrenberg H.M.
        • Huston-Presley L.
        • Catalano P.M.
        The influence of obesity and gestational diabetes mellitus on accretion and the distribution of adipose tissue in pregnancy.
        Am J Obstet Gynecol. 2003; 189: 944-948
        • Kac G.
        • Benicio M.H.
        • Velasquez-Melendez G.
        • Valente J.G.
        Nine months postpartum weight retention predictors for Brazilian women.
        Public Health Nutr. 2004; 7: 621-628
        • Lederman S.A.
        • Paxton A.
        • Heymsfield S.B.
        • Wang J.
        • Thornton J.
        • Pierson Jr., R.N.
        Body fat and water changes during pregnancy in women with different body weight and weight gain.
        Obstet Gynecol. 1997; 90: 483-488