Seminars in Fetal & Neonatal Medicine 17 (2012) 377e378
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Lessons from the current literature
Pregnancy outcomes in women after bariatric surgery compared with obese and morbidly obese controls Luc Cornette Department of Neonatology, AZ St Jan Bruges Ostend AV, Ruddershove 10, B-8000 Bruges, Belgium
J Lesko and A Peaceman Obstet Gynecol 2012;119:547e554
Abstract Pre-pregnancy obesity has become an increasing problem among women of reproductive age, and has been associated with increased rates of gestational diabetes (due to insulin resistance), pre-eclampsia, as well as adverse perinatal outcomes and comorbidities in case of pregnancy. In this retrospective study, the authors investigate the rates of gestational diabetes and hypertensive disorder of pregnancy in 70 women who had a singleton pregnancy after bariatric surgery. Four pregnant control patients (who not had bariatric surgery) were randomly selected for each case patient: two morbidly obese patients, i.e. with a BMI similar to the average pre-bariatric surgery BMI and two obese patients, i.e. with a BMI similar to the average postbariatric surgery pre-pregnancy BMI. Patients in case and both control groups with pre-existing chronic hypertension or diabetes were removed from the calculations. Multivariate logistic regression was performed to control for confounders. The conclusions were threefold: 1. no cases of gestational diabetes (0.0%) were identiﬁed after bariatric surgery as compared with: 16.4% in morbidly obese patients - OR 0.04, CI 0.00-0.62, P < 0.01; 9.3% in obese patients - OR 0.07, CI 0.00-1.20, P ¼ 0.01. 2. There was no signiﬁcant difference in the rate of hypertensive disorders of pregnancy after bariatric surgery. 3. Neonates were signiﬁcantly more small for gestational age (SGA) in the bariatric surgery group (17.4%) compared to the morbidly obese group (5.0%) (OR 3.94, CI 1.47e10.53, P < 0.01). Perinatal mortality rate was higher within the bariatric surgery group compared to both control groups together (n ¼ 4 versus n ¼ 1, respectively).
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. 1744-165X/$ e see front matter http://dx.doi.org/10.1016/j.siny.2012.08.002
Comments When reading the current literature on pregnancy after bariatric surgery, one should keep in mind this literature is limited primarily by (1) small numbers, reported in retrospective studies and thus lack of power to detect signiﬁcant differences in outcomes, (2) heterogeneous control groups, and (3) sources of bias (e.g. surveys conducted on patients whose pregnancies occurred several years prior, different types of bariatric surgery). These methodological weaknesses may lead to an underreporting of maternal and fetal/neonatal problems after bariatric surgery. The current study, whilst being single-institute and retrospective in design, examined a large case group, including controls. The data support several ﬁndings of previous investigators with regard to improved pregnancy outcomes for women after bariatric surgery, especially a decrease of gestational diabetes. Most likely as a result of this, neonates of bariatric surgery patients were less macrosomic compared to both control groups. Although other studies report contrary results, the current study additionally reports a clear and signiﬁcant increase in SGA neonates after bariatric surgery. Such is likely to be caused by maternal malnutrition or malabsorption resulting in deﬁciencies of iron, folic acid, fat soluble vitamins (vit K!), vitamin B12, calcium and protein. How then can we overcome this problem of SGA? The answer is complex as we lack clear, evidence-based guidelines for medical nutrition therapy of the (pre)-pregnant bariatric patient. Firstly, a comprehensive team of health care professionals including dieticians should be involved, ensuring a careful correction of nutritional deﬁciencies during the pre-pregnancy phase, as well as detection of eating disorders. Secondly, the team must ensure compliance with daily multivitamin supplementation during pregnancy. It remains important to re-iterate that over-the-counter multivitamin and mineral supplements do not provide adequate amounts of vitamin B12, iron, or fat-soluble vitamins. These patients do require additional doses of prophylactic supplementation to maintain optimal micronutrient status. And thirdly, even if patients continue to be overweight after bariatric surgery, there is never a recommendation for weight loss during pregnancy. However, it may be helpful to agree a restrictive 2.000 kcal diet with the patient, in order to avoid a too massive weight gain during pregnancy.
L. Cornette / Seminars in Fetal & Neonatal Medicine 17 (2012) 377e378
As to the future, two types of studies are needed. On the one hand, we need results from large cohorts of consecutive patients with pregnancies after bariatric surgery, in order to conﬁrm the ﬁndings of more SGA infants. On the other hand, as fetal nutrition is
the origin of adult diseases (Barker’s hypothesis), long-term followup of these SGA infants is strongly needed, in order to further determine the effect of pre-pregnancy bariatric surgery on childhood susceptibility towards obesity and diabetes.