Bariatric Surgery Before Pregnancy May Improve Pregnancy Outcomes in Obese Women

News Author: Laurie Barclay, MD
CME Author: Charles Vega, MD, FAAFP

CME Released: 11/18/2008; Valid for credit through 11/18/2009
This article is a CME certified activity. To earn credit for this activity visit:
http://cme.medscape.com/viewarticle/583749

November 18, 2008 — Women who have had bariatric surgery and then become pregnant have a lower risk for adverse pregnancy outcomes vs obese pregnant women, according to the results of a clinical review reported in the November 19 issue of the Journal of the American Medical Association.

"Use of bariatric surgery has increased dramatically during the past 10 years, particularly among women of reproductive age," write Melinda A. Maggard, MD, MSHS, from Rand Corporation, Santa Monica, California, and colleagues. "Our specific goals were to estimate the incidence of bariatric surgery in women aged 18 to 45 years and perform a systematic review to assess associations of bariatric surgery on pregnancy outcomes, including maternal and neonatal outcomes, nutritional adverse events, fertility, contraception, optimal time to delay pregnancy, and surgical complications during pregnancies."

The reviewers searched the Nationwide Inpatient Sample (1998-2005) and the electronic databases Medline, EMBASE, Controlled Clinical Trials Register Database, and the Cochrane Database of Reviews of Effectiveness for articles published between 1985 and February 2008 on bariatric surgery performed in women of reproductive age, using the search terms bariatric procedures, fertility, contraception, pregnancy, and nutritional deficiencies. The reviewers abstracted data regarding study design; fertility; and postoperative nutritional, neonatal, and pregnancy outcomes.

The review included 75 of 260 screened articles. Of all patients undergoing bariatric surgery, nearly half (49%) were women aged 18 to 45 years. For the 3 most recent years, there were approximately 50,000 cases each year.

In 3 matched cohort studies, rates of maternal complications were lower in women who had bariatric surgery vs obese women who did not have bariatric surgery, and rates were nearly similar for women who had bariatric surgery to those in nonobese control subjects. One matched cohort study compared maternal complication rates in women after laparoscopic adjustable gastric band surgery vs those in obese women who did not undergo surgery. In that cohort, the bariatric surgery group had lower rates of gestational diabetes (0% vs 22.1%; P < .05) and preeclampsia (0% vs 3.1%; P < .05). Thirteen other bariatric cohort studies showed similar findings.

The bariatric surgery group also fared the same or better in neonatal outcomes vs the group of obese women who did not undergo laparoscopic adjustable gastric band surgery. Complication rates were 7.7% vs 7.1% for premature delivery and 7.7% vs 10.6% for low birth weight (P < .05) and 7.7% vs 14.6% for macrosomia (P < .05). Compared with nonobese control subjects, the gastric bypass group had no differences in premature delivery (26.3% - 26.9% vs 22.4% - 20.2%), low birth weight (7.7% vs 9.0%), and macrosomia (0% vs 2.6% - 4.3%). Ten other studies supported these findings; however, studies of nutrition, fertility, cesarean delivery, and contraception were limited.

"Rates of many adverse maternal and neonatal outcomes may be lower in women who become pregnant after having had bariatric surgery compared with rates in pregnant women who are obese; however, further data are needed from rigorously designed studies," the review authors write.

Limitations of this study include those of the original studies, including modest sample sizes and lack of randomization.

"Because clinicians must still make decisions regarding these patients, we assessed the best evidence available in an attempt to help guide clinicians," the review authors conclude. "Research is needed to better delineate the extent to which surgery and subsequent weight loss improve fertility and pregnancy outcomes. Optimizing success for contraception and producing healthy neonates following surgery will require a multidisciplinary effort by surgeons, primary care physicians, reproductive fertility specialists, obstetricians, and patients."

The Agency for Healthcare Research and Quality supported this study. Dr. Maggard has received a grant from the Robert Wood Johnson Physician Faculty Scholars program. The other review authors have disclosed no relevant financial relationships.

JAMA. 2008;300:2286-2296.

Clinical Context

An increasing number of patients are choosing the option of bariatric surgery to lose weight. A study by Santry and colleagues, which was published in the October 19, 2005, issue of the Journal of the American Medical Association, examined trends in the use of bariatric surgery in the United States from 1998 to 2002. During this interval, the estimated number of bariatric surgical procedures increased from 13,365 in 1998 to 72,177 in 2002. Gastric bypass procedures accounted for more than 80% of all bariatric surgical procedures, and the average length of hospital stay after bariatric surgery decreased from 4.5 days in 1998 to 3.3 days in 2002. Less than 10% of patients required a second operation for unexpected complications, and the adjusted in-hospital mortality rate ranged from 0.1% to 0.2%.

Santry and colleagues also recorded an increasing percentage of women undergoing bariatric surgery during the study period. The current study examines pregnancy and neonatal outcomes in women who underwent bariatric surgery.