Volume 200, Issue 5 , Pages e34-e36, May 2009
Relationship of obesity to outcome of medical abortion
Article Outline
Objective
The purpose of this study was to compare the outcome of medical abortion for obese women and nonobese women.
Study Design
We conducted a chart review of women having medical abortions in 2005-2007. Outcomes were classified as surgical intervention, need for additional visits, and complete abortion. The rate of surgical intervention was compared for women with BMI less than 30 to women with BMI greater than 30.
Results
Of the 1202 eligible procedures using mifepristone and misoprostol, there were 861 women with BMI less than 30 and 341 women with BMI greater than 30. Women with BMI less than 30, and women with BMI greater than 30 had identical rates of surgical intervention, 5% and 6%, respectively (P = .72).
Conclusion
In light of the additional risks of surgical abortion to obese women, medical abortion should be considered for these women.
Key words: body mass index, medical abortion, mifepristone, obesity
Obesity is defined by the World Health Organization as a body mass index (BMI) of 30 or more. Class I is defined as BMI of 30-34.9, class II is defined as BMI of 35-39.9, and class III is defined as BMI of 40 or more.1 In 2005-2006, 30.5% of US women aged 20-39 were obese.2 Obesity has been associated with increased risk of poor reproductive outcomes, including poor pregnancy outcomes, increased risk of cesarean delivery, and greater risk of surgical complications.3 Surgical abortion for obese women is associated with longer operating times, increased technical difficulty, increased blood loss, and increased risk of thromboembolism.4, 5, 6, 7 There are no published studies comparing the outcomes of medical abortion for obese and nonobese women. We sought to determine whether there is a difference in the outcome of medical abortions for obese women and nonobese women.
Materials and Methods
We conducted a retrospective chart review of 1398 medical abortions performed at Boston Medical Center from January 1, 2005 through December 31, 2007. During this period, medical abortions of pregnancies up to 63 menstrual days were performed with mifepristone 200 mg orally and misoprostol 800 μg vaginally or buccally within 24 hours. Relevant information was extracted from the electronic medical record, including age, ethnic group and parity, gestational age at the time of abortion, and BMI (weight [in kg] divided by height [in m2]). Records were excluded if the woman had a nonviable pregnancy or incomplete abortion, was younger than 18 years of age, or if mifepristone was not used. If a woman had more than 1 medical abortion, we considered only the first 1. Women whose BMI was less than 30 (nonobese) were compared to women whose BMI was greater than 30 (obese).
The primary outcome was defined as the rate of surgical intervention (uterine aspiration) within 2 weeks of treatment with mifepristone, which is typically about 5%.8 The sample size was calculated using N-Query Advisor for unequal sample sizes for the 2 groups with 4:1 ratio, based on the prevalence of obesity. To have a power of 80% to detect a difference between the 2 groups of 7% at P < .05, we needed 1200 women. This sample size accounts for an expected 15% lost to follow-up rate and 5% incomplete data rate. Secondary outcomes included documented complete medical abortion within 2 weeks of initial treatment, additional clinic visits or treatments, and loss to follow-up. The distribution of outcomes was examined using the χ2 test for discrete data and Student t test for continuous data. Demographic profiles of the groups were compared. Multiple logistic regression models were constructed to account for demographic and medical differences that might affect the outcome. Statistical analysis was carried out with SAS (Version 9.1; SAS Institute, Inc, Cary, NC). The study was approved by the Boston University Institutional Review Board.
Results
There were 1398 women who had a medical abortion at Boston Medical Center from January 2005 to December 2007. Records were excluded for repeat procedures (131), nonviable pregnancies (28) and missing data (28), if mifepristone was not used (10), and if the patient was a minor (8). There were 1202 records eligible for inclusion. There were 861 women with a BMI less than 30 (72%), and 341 with BMI greater than 30 (28%). Demographic data are shown in Table 1. There were several differences between the 2 groups. The obese group was significantly older than the nonobese group (P = .001), and more likely to be parous than the nonobese group (P = .001). The racial distribution between the 2 groups was also different (P = .001).
TABLE 1. Demographic characteristics
| Demographic | BMI < 30 (n = 861) | BMI > 30 (n = 341) | P value |
|---|---|---|---|
| Age (y) | 26 | 28 | .001a |
| Parity: 0 | 269 (31%) | 64(19%) | .001b |
| > 0 | 592(69%) | 277(81%) | |
| Gestational age (d) | 48 | 48 | .97a |
| Race: | |||
| African American | 459(53%) | 235(69%) | .001b |
| White | 144(17%) | 48(14%) | |
| Hispanic | 137(16%) | 36(11%) | |
| Other | 121(14%) | 22(6%) |
aMean/Student t test; |
bProportion/χ2 test. |
Outcomes are shown in Table 2. There was no significant difference in the rates of surgical intervention between the obese and nonobese groups, which were 5% and 6%, respectively (P = .72). The need for additional clinic visits and medications was also similar. The surgical intervention rates and complete abortion rates were similar for all BMI groups (Figure 1). Logistic regression models were constructed to account for demographic differences, and the outcomes were unchanged. Increasing parity and gestational age had a weak association with surgical intervention. There were no infections, hemorrhage, or hospitalizations.
TABLE 2. Outcomes of medical abortion
| Outcome | BMI < 30 (n = 861) | BMI > 30 (n = 341) | P valuea |
|---|---|---|---|
| Surgical intervention | 46(5%) | 20(6%) | .72 |
| Documented complete medical abortion | 699(81%) | 274(83%) | .68 |
| Additional follow-up visits | 101(11%) | 12(9%) | .58 |
| Additional medicationsb | |||
| Subsequently completed abortion medically | 57(6%) | 17(5%) | .29 |
| Subsequently had uterine aspiration | 13(1.5%) | 5(1.5%) | .96 |
| Lost to follow-up | 116(13%) | 47(14%) | .88 |
aχ2 test. |
bMisoprostol 800 μg vaginally. |
FIGURE 1.
Outcome of medical abortion according to BMI
The distribution of outcomes of abortion is similar regardless of BMI group.
Strafford. Obesity and medical abortion. Am J Obstet Gynecol 2009.
When additional comparisons were constructed in BMI categories as shown in Figure 1, eg, comparison of normal weight to very obese women, none of the comparisons were significant at the P < .05 level.
Comment
We found that the outcomes of medical abortion are similar for both obese and nonobese women. The rates of undesired outcomes (surgical intervention) appear similar across all BMI categories. These findings persisted when possible confounding factors were evaluated. A strength of the study is the use of electronic medical records, allowing for complete data retrieval, with few (1.5%) charts excluded for incomplete data. A weakness of the study is the loss to follow-up rate.
In light of the potential additional risks for obese women having surgical abortions, medical abortion should be considered. Medical abortions are typically performed before 63 menstrual days. In order to keep the option of medical abortion available, early counseling and referral is important for obese women.
References
- . Obesity: preventing and managing the global epidemic. Report of a WHO convention, Geneva, 1999. WHO technical report series 894. 2000;Geneva, Switzerland
- . Obesity among adults in the United States—no changes since 2003-2004 (NHCS data brief no 1). Hyattsville, MD: National Center for Health Statistics; 2007;
- . Committee opinion no. 315: obesity in pregnancy. Obstet Gynecol. 2005;106:671
- . Family planning for obese women: challenges and opportunities. Contraception. 2005;72:1–4
- . Intraoperative blood loss and gestational age at pregnancy termination. Prim Care Update Obstet Gynecol. 1998;5:204–205
- . Obesity and second-trimester abortion by dilation and evacuation. J Reprod Med. 2002;47:226–230
- . Deaths caused by pulmonary thromboembolism after legally induced abortion. Am J Obstet Gynecol. 1978;132:169–174
- . Medical termination of pregnancy. N Engl J Med. 2000;342:946–956
Reprints not available from the authors.
PII: S0002-9378(08)02029-2
doi:10.1016/j.ajog.2008.10.016
© 2009 Mosby, Inc. All rights reserved.
Volume 200, Issue 5 , Pages e34-e36, May 2009
