Pregnancy: a “teachable moment” for weight control and obesity prevention

The link between pregnancy and obesity 

An important contributing factor to weight gain among young adult women is sustained weight retention after pregnancy. Although studies of the general population have reported average weight gains of only 0.4-3.8 kg more than aging,8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18 there is marked variability in weight changes that are associated with pregnancy. Approximately 25% of women experience weight retention of ≥4.5 kg in association with pregnancy.15, 19, 20, 21 Moreover, weight changes at the time of pregnancy are related strongly to subsequent weight change. In 2 large prospective studies, weight gains during the pregnancy and weight changes during the year after delivery were both independently related to the development of overweight22 or weight gain23 at 15 and 10 years follow-up evaluations, respectively. Linne et al24 reported that 45.6% of normal weight individuals who gained excessive amounts of weight during pregnancy (average, 18.8 kg) shifted from normal weight to overweight at the 15-year follow-up evaluation (Figure 1). Moreover, 43.8% of normal-weight women who had retained significant amounts of weight at 12 months after delivery (M = 4.8 kg) had become overweight by the 15-year follow-up evaluation. Rooney and Schauberger23 reported that women who were back to their prepregnancy weight by 6 months after delivery gained only 2.4 kg over the next 10 years, whereas those who retained weight after delivery gained 8.3 kg over the 10-year follow-up period. Thus, high gestational weight gain and postpartum weight retention appear to set the stage for future weight gain and the development of obesity in women.

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FIGURE 1. Prevalence of overweight and obesity among women who had low, middle, and high weight gains during pregnancy Women who experienced low-weight gain gained an average of 9.8 ± 1.9 kg; women who experienced middle-weight gain gained an average of 14.0 ± 0.9 kg; and women who experienced high-weight gain gained an average of 18.8 ± 2.3 kg during pregnancy. Adapted from Linne et al.22 Phelan. Teachable moment: weight control and obesity prevention. Am J Obstet Gynecol 2010.

Variables associated with high postpartum weight retention provide targets for intervention 

The strongest predictor of 1-year postpartum weight retention is the amount of weight gained during pregnancy.21, 22, 23, 25, 26 The Institute of Medicine (IOM) guidelines were developed in 1990 to provide recommended ranges of weight gain to optimize fetal growth and maternal/infant outcomes. Recently, the recommendations were revised to use the BMI cutpoints from the World Health Organization (eg, overweight = 25.0-29.9 km/m2 instead of 26.0-29.9 km/m2) and provide a specific range of weight gain for obese women (≥30.0 km/m2), previously lacking from the 1990 guidelines (Table).27, 28 Despite the wide adoption of the 1990 IOM guidelines, however, many women continue to gain more than the recommended amount. Available data suggest that 37% of normal-weight women and 64% of overweight women gain more that IOM recommendations.19, 29 Although there is a broad range of weight changes that are associated with healthy pregnancy outcomes,30 weight gains that exceed the IOM recommended levels have been connected to gestational complications (hypertension, diabetes mellitus, and preeclampsia), complications in delivery (cesarean section deliveries), babies that are large for gestational age (macrosomia),31, 32, 33, 34, 35 and obesity in offspring by age 3 years.36, 37 Weight gains outside IOM recommendations are also associated with greater postpartum weight retention and an increased risk of future overweight.38, 39, 40, 41 Thus, to prevent postpartum weight retention, it is critical to try to prevent excessive weight gain during pregnancy.42

TABLE. The 2009 Institute of Medicine recommendations for total weight gain ranges for pregnant women

	Body mass index category (kg/m2)	Recommended total gestational weight gain
		kg	lb
	<18.5	12.5-18	28-40
	18.5-24.9	11.5-16	25-35
	25.0-29.9	7-11.5	15-25
	>30.0	5-9	11-20

Adapted from the 2009 Institute of Medicine report.28 Phelan. Teachable moment: weight control and obesity prevention. Am J Obstet Gynecol 2009.

Behaviors during pregnancy have also been found to relate to the risk of excessive gestational weight gain (Figure 2).43, 44, 45, 46, 47 Olson and Strawderman45 evaluated multivariable biopsychosocial models of gestational weight gain in 622 healthy women. In the final adjusted model, women who reported eating “much more” food during mid pregnancy were 2.35 times more likely than women who ate “a little more” food to gain too much weight in pregnancy. Moreover, women who were less physically active during pregnancy than before pregnancy were 1.7 times more likely to gain more than recommended than those who maintained or increased their physical activity. Other studies have reported similar findings and also have shown additional relationships with excessive gestational weight gain and high fat intake,43 low fiber intake,43 and high intake of sweets.43 These findings suggest that targeting healthy eating and modest physical activity during pregnancy may help to improve maternal weight gain outcomes (Figure 2).

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FIGURE 2. Variables related to excessive gestational weight gain Phelan. Teachable moment: weight control and obesity prevention. Am J Obstet Gynecol 2010.

At-risk populations 

Certain subgroups of women appear to be at greater risk of high gestational weight gain than others and may benefit from interventions to promote healthy weight gain during pregnancy. Many studies have found that prepregnancy weight is a significant predictor of weight changes during pregnancy. Although overweight women gain less weight than normal-weight women during pregnancy, women who are overweight before pregnancy appear more likely to exceed IOM weight gain guidelines (with the 1990 IOM overweight criterion of BMI ≥26 kg/m2) compared with normal-weight women.30, 48, 49 The multiple risks that are associated with excess gestational weight gain may be compounded by risks that are associated with high prepregnancy BMI.50, 51, 52, 53 Compared with normal-weight women, obese pregnant women have an increased risk of early-trimester loss and recurrent miscarriage54 and congenital anomalies that include neural tube defects, heart defects, and omphalocele.55, 56, 57 Other complications include chronic hypertension, pregnancy-induced hypertension, pregestational diabetes mellitus, gestational diabetes mellitus, postdate delivery,58, 59, 60, 61, 62 urinary tract infection,63 asthma, obstructive sleep apnea, and gallbladder disease.60, 64, 65 Numerous delivery,66 operative,67 and postpartum68, 69, 70, 71 complications are also associated with prepregnancy obesity. Moreover, maternal obesity has a significant impact on offspring risks, which include higher rates of fetal macrosomia, still birth72, 73 and childhood obesity.74

Weight loss before conception is likely to be an effective way to decrease complications that are associated with pregnancy in obese women; however, limited research has been conducted in this area. Bariatric procedures before conception have been found to reduce significantly the rates of pregnancy-induced hypertension and gestational diabetes mellitus,75 chronic hypertension, pregestational diabetes mellitus, and large-for-gestational-age infants.76 However, bariatric surgery is a potential option for only a small subset of women who have a BMI >35 kg/m2, comorbid conditions, history of failed nonsurgical interventions, acceptable operative risks, and motivation to adhere to long-term postsurgical dietary regimen.77 Practitioners may consider advising effective nonsurgical weight loss strategies before conception, which would include daily self-monitoring food intake,78, 79, 80, 81 daily self-weighing,79, 80, 81, 82 and consuming meal replacement products, typically for 2 meals a day initially and then 1 meal a day long term.83, 84 However, because physicians often cannot devote the time that is needed to help a patient with their weight loss efforts, it may be useful to refer patients to other programs that can provide more intensive assistance with weight loss before conception.85 Ideally, efforts to promote prepregnancy weight control should be carried over during pregnancy to prevent excessive gestational weight gain.

Race may also affect pregnancy weight changes. African American women consistently gain less weight than white women during pregnancy.19, 26, 41 However, they are generally no different from white women in terms of falling above, at, or below IOM guidelines.41, 48 Age also affects weight gain during pregnancy; younger women gain more weight than older women, but this effect may be due to high weight gain during growth in adolescent women.86 Primiparity is also associated with larger weight gains during pregnancy. Abrams and Parker86 found that weight gains of women with parity of 0, 1, or ≥2 were 34.0, 33.2, and 31.5 lbs, respectively. In another study, 34% of primiparous women exceeded the 1990 IOM guidelines; only 16% of multiparous women exceeded the guidelines.26

Smoking cessation is strongly recommended during pregnancy because, in part, of its association with low infant birthweight.87 Studies that have compared women who do not smoke with those who continue to smoke have found that nonsmokers tend to gain more weight than smokers.26 Smoking during pregnancy has also been associated with increased risk of obesity in the offspring.88, 89 Low income has been related to greater risk of exceeding weight gain guidelines.90, 91 Finally, genetic factors may contribute to the rate of gestational weight gain.92

Pregnancy as a “teachable moment” 

The label teachable moment has been used to describe naturally occurring life transitions or health events that are thought to motivate individuals to spontaneously adopt risk-reducing health behaviors; the concept of “teachable moments” has a strong foundation in widely accepted conceptual models of behavior.93, 94

McBride et al95 recently proposed a model to describe characteristics of effective teachable moments using smoking cessation as an example. Teachable moments were characterized as times that (1) increase perceptions of personal risk and outcome expectancies, (2) prompt strong affective or emotional responses, and (3) redefine self-concept or social roles. McBride et al95 posited that the greater the degree to which a health event alone or in combination with a proximally timed intervention influences all 3 domains, the greater the likelihood the event will prompt behavioral change.

With this model, pregnancy may be conceptualized as a powerful “teachable moment.” Pregnancy provides an immediate and personal experience with risk that is related to the health of the mother and baby and enhances the perceived value of healthy eating and exercise.96, 97 Moreover, the emotional responses that surround pregnancy may also make it an opportune time to initiate change. Emotional responses are thought to influence an individual's judgment about the significance and meaning of an event.94 Pregnancy may prompt feelings of elation and fear about the well-being of the fetus, which may motivate women to change their eating and exercise habits.

Finally, consideration of the pregnancy's impact on social role and self-concept is important in viewing it as a “teachable moment.” Clearly, pregnancy is a time when personal and social roles change as women become mothers in addition to their other roles. Primiparous women are adopting the maternal role for the first time, which carries expectations for major changes in lifestyle and self-image.98, 99 Women are also becoming a role model for their new child, which, again, may have implications for adopting healthy eating and exercise habits. Thus, intervening during pregnancy may capitalize on this natural period of redefinition that occurs among women (Figure 3).

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FIGURE 3. Pregnancy as a “teachable moment” for weight control Reprinted and adapted with permission from McBride et al.95 Phelan. Teachable moment: weight control and obesity prevention. Am J Obstet Gynecol 2010.

Weight gain prevention interventions during pregnancy 

A handful of studies have evaluated interventions during pregnancy to promote weight gain within recommendations and prevent postpartum weight retention. Gray-Donald et al100 examined the effects of periodic dietary counseling on weight gain in a nonrandomized study of the Cree population. The intervention was found to have only a minor impact; the authors noted that cultural factors, however, likely limited the intervention's efficacy in the Cree population.100 In another nonrandomized study, Kinnunen et al101 examined the effects of an intervention that included 4 dietary counseling sessions with a public health nurse. Results indicated that more women in intervention clinics than control clinics made the dietary changes that were targeted by the intervention (higher intakes of vegetables, fruits, berries, and high-fiber bread), but no significant group differences in magnitude of gestational weight gain were observed.

Studies that have included a focus on weight monitoring and more intensive counseling sessions have found significant effects on gestational gain. Olsen et al102 conducted a study that evaluated the effects of periodic weight monitoring, graphing, and education to prevent excessive weight gain during pregnancy in a sample of women from upstate New York. Results indicated that, in the lower-income women, 33% exceeded weight gain recommendations in the intervention groups, compared with 52% in the historic control group. However, no effect was found among the higher income women. Claesson et al103 conducted a nonrandomized evaluation of an intervention program in Sweden for obese women that included weekly 30-minute counseling sessions (focused on weight control and motivation and conducted by midwives) and weekly (1-2 times/wk) aqua aerobic classes. Results indicated that the intervention succeeded in reducing the magnitude of weight gain during pregnancy (7.5 vs 9.8 kg, respectively) and 12-week postpartum weight retention (–3.3 vs –0.52 kg, respectively), independent of socioeconomic status.

Only 3 randomized, controlled trials have evaluated intervention effects on weight gain during pregnancy; all studies had sample sizes <120 women. Polley et al104 examined whether a behavioral intervention that was delivered during pregnancy could decrease the percentage of women who gained more than the 1990 IOM recommendations. Results indicated that the intervention was successful in decreasing the percentage of normal-weight women who exceeded the IOM recommendations relative to no-treatment control women (33% vs 58%, respectively); no effect was found in overweight women, but a trend in the opposite direction was observed. Asbee and colleagues105 examined the effects of an intervention that included weight monitoring and brief, provider-based feedback at patients' regularly scheduled prenatal visits. The intervention significantly reduced weight gain compared with routine prenatal care (13.0 kg vs 16.1 kg, respectively), but did not significantly decrease the precentage of women who exceeded IOM recommendations. In another randomized trial of 50 obese women from Denmark, Wolff et al106 examined the effects of 10, 1-hour dietary counseling sessions in reducing gestational weight gain. The intervention was found to restrict gestational weight gain significantly relative to control subjects (6.6 kg vs 13.3 kg, respectively).

These preliminary studies suggest that monitoring weight gain, quantity of food intake, and physical activity are appropriate behavioral targets and, combined with behavioral counseling, appear to curb excessive gestational weight gain and postpartum weight retention. However, larger randomized controlled trials are needed to test adequately the effects of behavioral intervention during pregnancy on the long-term weight retention and obesity.

Are there adverse effects of intervening during pregnancy? 

Available data suggest that the prevention of excessive weight gain during pregnancy does not have adverse consequences and may, in fact, benefit the developing fetus and mother. In Asbee et al's105 randomized trial, the intervention significantly reduced the number of cesarean deliveries due to “failure to progress” compared with standard care (25% vs 58.3%). In the randomized trial of Wolff et al,106 the intervention did not have any detectable adverse effects on fetal growth, and fewer incidences of pregnancy and birth complications were observed in the intervention than in the control group. Similarly, Claesson et al103 found no significant differences between intervention and control groups regarding mode of delivery and neonatal outcomes. Neither Gray-Donald et al100 nor Polley et al104 nor Olson et al102 found any differences in birthweight between intervention and control groups. However, results of these studies require further investigation in larger randomized controlled trials.

Although there are certain contraindications to exercise during pregnancy (eg, pregnancy-induced hypertension, incompetent cervix), research on moderate aerobic exercise shows that exercise does not appear to have a negative effect on the developing fetus.107, 108 Kulpa et al107 randomly assigned pregnant women to usual care or an exercise condition and found that the exercise intervention significantly reduced the amount of pregnancy weight gain (27 lb vs 34 lb) with no adverse effects on gestational age, birthweight, Apgar scores, or obstetric complications. Based in part on these data, current recommendations by the American College of Obstetricians and Gynecologists are in line with the Centers for Disease Control and Prevention and American College of Sports Medicine recommendation for exercise: to accumulate ≥30 minutes of moderate exercise on most, if not all, days of the week in the absence of either medical or obstetric complications.109, 110

Talking to patients about appropriate weight gain 

There is strong evidence that prenatal care providers are either not providing weight gain advice or not following the IOM guidelines when they advise their patients. Approximately one-third of women report receiving no weight gain advice from their prenatal care provider;111, 112 among those patients who receive advice, approximately one-third of the women report receiving advice that is inconsistent with the 1990 IOM guidelines.111 Stotland et al111 evaluated 1198 women and found that 50% of the participants with a high BMI (>26 kg/m2) reported receiving advice to over gain; by contrast, 35% of the participants with a low BMI (<19.8 kg/m2) report receiving advice to under gain.111 Similar findings have been reported elsewhere.34 Reasons for lack of provider adherence to IOM guidelines include lack of awareness, familiarity, and agreement with guidelines.113, 114 Some providers may not be aware of the BMI specific weight gain guidelines and advise all women to gain within the same range.111 Also, providers may reduce their weight gain goals for obese patients but overlook more moderate degrees of overweight.111 In addition, weight gain during pregnancy is a sensitive topic for many patients, and providers may be reluctant to broach the issue.115

Nonetheless, in the absence of definitive empiric findings to guide practice, providing weight gain goals and graphing weight gain during pregnancy in relation to the current IOM recommendations would appear to be a step to at least reduce the likelihood of excess pregnancy weight gain. Provider advice about gestational weight gain is strongly associated with actual weight gain outcomes.34, 111, 116 Although there is a wide range of weight gain associated with healthy pregnancy outcomes,117 patients who are exceeding recommendations may be advised to “check-in” with their health behaviors and modify any unhealthy eating and exercise habits.104 Promoting physical activity and discouraging sugar-sweetened beverage intake and fast-food consumption may also contribute to the prevention of excessive gestational weight gain and promote healthy postpartum habits.38 Weight gain graphs (based on the 1990 guidelines) and educational materials to promote healthy gestational weight gain are available online from the study by Olson et al.102

Advantages of intervening during pregnancy include capitalizing on pregnancy's potential as a “teachable moment” and implementing interventions in the context of usual prenatal care. However, translating research findings into clinical practice remains a challenge.99, 118, 119 In practice, financial barriers may prohibit patients from being able to afford, for example, the cost of a scale or transportation to attend clinic visits. Patient adherence to recommended strategies (eg, weight graphing, physical activity), particularly among diverse patient populations during pregnancy, remains understudied. In clinical practice, a pregnant patient may be seen by multiple practitioners and at varying time intervals, which makes consistent goal-setting and follow-up evaluation with behavioral goals a challenge. Providing educational materials and behavioral counseling may also prove difficult within the time constraints of clinical practice. More research is needed to identify the most effective and disseminable intervention for the promotion of appropriate gestational weight gain within the context of our current health care system. Barriers to providing advice about appropriate weight gain also need to be addressed, including the role of patient adherence, financial barriers, limited physician time, and lack of payment by health-insurance and managed-care plans.120, 121, 122 To combat the rising obesity epidemic, multilevel interventions across the lifespan will need to be implemented.123 By monitoring and giving appropriate advice about gestational weight gain, health care providers have the potential to influence weight gain during pregnancy and reduce the incidence of overweight and obesity in women and children.