Materials and Methods
After receiving Institutional Review Board approval at the seven participating institutions, by December 31, 1997 359 women entered into two clinical trials to examine adjustable gastric bands for treating morbid obesity. The first adjustable gastric band trial began on December 18, 1990 and stopped enrollment on August 28, 1995. The second trial began in June 1995, when a modification of the adjustable gastric band system allowing laparoscopic placement became available, and ended May 1998.
Data for this study were compiled at the Louisiana State University Health Science Center in New Orleans. There were 162 women in the first trial and 197 women in the second trial. Among 359 participants, 40 had hysterectomies and 54 had tubal sterilizations, leaving 265 fertile women. The mean age of the women in both studies was 37 years (range 18–51 years). Mean preoperative weight was 131.4 kg (range 90.9–234.5 kg) and the mean was 48 kg/m2 (range 37–74 kg/m2). A BMI of at least 35 kg/m2 (definition of morbid obesity) was an entry requirement and was developed from the recommendations of the 1991 National Institutes of Health Consensus Conference on Surgical Treatment for Morbid Obesity.1,16 A summary of entry criteria for surgical intervention and descriptions of outcome results of the treatment were published.13,17 Fertile women were instructed to delay pregnancy during the first postoperative year so that accurate weight loss curves could be developed.
Data collected perioperatively included medical histories, physical examinations, laboratory tests, x-ray studies, health status questionnaires, operative findings, and concurrent procedures. Follow-up data included weight, symptoms, complications, adverse events, and band adjustment procedures, as well as x-rays, laboratory reports, and health-related quality-of-life questionnaires. Subjects were examined quarterly the first year and at 6-month intervals in subsequent years.
Subjects were entered at seven different sites, three of which participated in both studies. When possible, site coordinators interviewed subjects who became pregnant to collect specific pregnancy information to complete adverse experience reports required by the Food and Drug Administration for implantable medical devices.
Of the 265 fertile study subjects, 20 completed 23 pregnancies as of December 31, 1997. Two pregnancies occurred after tubal ligation, one an ectopic pregnancy and the other producing a full-term infant. There was no difference between those who became pregnant and those who did not, except for a mean age of 29 years (range 19–39 years), versus 37 years, respectively.
Two women had first-trimester miscarriages and two had elective abortions. None had complications related to obesity. There were no reports of diabetes, hypertension, neural tube defects, or eclampsia. Among 18 deliveries, 14 were vaginal and four were cesarean deliveries (one urgently for decreased fetal heart rate, two for cephalopelvic disproportion, and one repeat cesarean for twins). All pregnancies were full term, and all fetal weights were normal. The mean birth weight was 3676 g (range 2381–3912 g). Three women had two pregnancies each during the study. Five women had their first pregnancies during the study, although all women had tried previously to conceive at heavier weights. Those five women lost between 3.8 and 18.4 kg (mean 10.6 kg) over 4 months to 2.5 years before becoming pregnant. The other 15 women who became pregnant lost between 3.3 and 26 kg (mean 12.0 kg) with six pregnancies within the first year postgenerative and the others up to 4 years postoperatively.
Two subjects gained approximately twice the weight that is recommended for women of normal weight (31 and 39 kg) during their pregnancies, and one woman who was carrying twins gained 27 kg. Women with the most weight gain had no fluid in their adjustable bands during pregnancy, therefore no restriction of their food intake. The woman who gained the most weight during her pregnancy requested her band to be emptied when her pregnancy was discovered. The other woman had fluid removed from her band by her surgeon to prevent band-related vomiting.
Three women required removal of fluid from the band for nausea and vomiting (one had a spontaneous abortion). Another asymptomatic woman requested removal of all fluid and lost 17.6 kg during her pregnancy. The other 12 women who kept the diameters of their bands constant during gestation had 1.5 to 4.0 mL in their bands, resulting in three subjects losing weight (1.8–7.6 kg) and nine gaining weight (1.4–25 kg) during their pregnancies. Adjustment of bands consistently relieved nausea and vomiting when they became medical concerns.
The percentage of obese young Americans is increasing faster than that of the rest of the population because of lower levels of physical work and exercise.11,18 Obstetricians can expect to see a greater percentage of obese pregnant women. The number of young women seeking surgical treatment for obesity should increase19 as the consequences of obesity (early death, comorbid medical conditions, discrimination, and lower incomes)10,12 become known more widely.
All eight of the pregnancies that occurred in the first year after placement of gastric bands were unexpected. Five women who had healthy full-term infants were nulliparous, and overall the group that became pregnant was younger. Despite the lack of statistical significance in the present study, women who have gastric band surgery should be aware of increased fertility and consider instituting contraception postoperatively.
The protocol for placing and adjusting the gastric bands emphasizes gradually increasing the degree of gastric restriction, while providing patients dietary and behavioral information. Weight loss by the end of the first postoperative year after restrictive operations such as adjustable gastric banding is not as great as that after malabsorptive bariatric procedures.10,13,17,20 Surgical malabsorptive procedures such as gastric bypass or biliopancreatic diversion have been associated with electrolyte, vitamin, and iron deficiencies.7–9 Pregnant women who have had restrictive operations should not have those problems if they take prenatal vitamins.5,7 The largest dimension of a vitamin pill should be less than 10 mm to fit through the restrictive gastric opening.
The fluid installation port is usually positioned high in the left rectus muscle during surgical placement. If manipulation of the port with fluoroscopy is required during pregnancy to remove fluid from the band to treat symptoms of nausea and vomiting, the pelvis can be protected by a lead apron. Access can be gained to some ports by touch, as with mediports used for chemotherapy, after sufficient weight loss. The adjustability of the band allows options to women and obstetricians if nausea and vomiting, weight loss, or inadequate fetal growth become concerns. Normal obstetric care with assessment of fetal growth should be done because of potential weight loss. In our series there was no fetal compromise, despite maternal weight loss.
Women who lose weight after placement of an adjustable gastric band report significant improvements in health status even within the first postoperative year.13,17 Weight loss might decrease the risk of complications from pregnancy. One-fourth of our subjects lost weight during their pregnancies, two during the first postoperative year (1.8 and 2.3 kg), and three during the second postoperative year (4.2, 7.7, and 17.6 kg). Two pregnant women who had gained the most weight had no restrictions in their gastric bands, eliminating any treatment benefits. Current recommendations for morbidly obese women who become pregnant include eating properly to maintain prepregnancy weight.
This study shows that pregnancy after adjustable gastric banding was not associated with complications in our population. The degree of restriction caused by the band probably does not need to be adjusted (eliminating effectiveness) at the onset of pregnancy. Adjustments of the degree of restriction might relieve nausea and vomiting. Other surgical procedures to treat morbid obesity are not flexible and have been associated with nutritional deficiencies. Our study size was limited, and further outcome studies are needed for women who have bariatric treatments.
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