Obesity is recognized as a global epidemic. Its worldwide prevalence has more than doubled in the past two decades, including 35% of the U.S. population.1 Bariatric surgery has become the mainstay of treatment for morbid obesity owing to its efficacy in achieving significant weight loss and in improving obesity-related comorbidities.2
Eighty percent of patients who undergo bariatric surgery are women of childbearing age.3 Furthermore, fertility in obese women generally improves after bariatric surgery because ovulatory problems and menstrual irregularities resolve after weight loss (Dilday J, Derickson M, Kuckelman J, Bader J, Ahnfeldt E, Martin M, et al. Sleeve gastrectomy for obesity in polycystic ovarian syndrome: weight loss and fertility outcomes [abstract]. Surg Obes Relat Dis 2017;13:S15.).4,5 As such, coupled with the rapidly growing use of bariatric surgery in the management of obesity, obstetricians are increasingly likely to encounter women who have undergone bariatric surgery in their practices.5
Current recommendations regarding care of pregnant women after bariatric surgery are based on studies involving patients who underwent laparoscopic Roux-en-Y gastric bypass and laparoscopic adjustable gastric banding.6–11 Laparoscopic Roux-en-Y gastric bypass was shown to be associated with a decreased risk of gestational diabetes and macrosomia along with an increased risk of small-for-gestational-age (SGA) neonates,6–9 whereas laparoscopic adjustable gastric banding was demonstrated to have no detrimental effect on birth weight.11,12 In recent years, laparoscopic sleeve gastrectomy, a restrictive procedure, has become the most frequently utilized bariatric procedure, surpassing laparoscopic Roux-en-Y gastric bypass.13–15 Hence, as the number of women of childbearing age undergoing laparoscopic sleeve gastrectomy increases rapidly, investigating its effect on pregnancy outcomes is vital. Given the paucity of publications, we performed a review of pregnancies among patients who underwent laparoscopic sleeve gastrectomy to examine possible associations of this procedure with maternal and perinatal outcomes.
MATERIALS AND METHODS
This is a retrospective case–control study. The study group comprised all singleton pregnancies of women with prior laparoscopic sleeve gastrectomy referred to two medical centers during 2006–2016. A control group of pregnant women who had not undergone bariatric surgery was established by matching, one-to-one, according to preoperative body mass index (BMI, calculated as weight (kg)/[height (m)]2) (in the control group, we considered early-pregnancy BMI), maternal prepregnancy age, parity, delivery history (eg, number of cesarean deliveries, zero, one, two or greater), and year of delivery. For women with more than one pregnancy after laparoscopic sleeve gastrectomy, only the first pregnancy was included.
We abstracted emergency department encounters, hospital admissions, outpatient clinic follow-up visits, labor and delivery charts, operation reports, and discharge letters from the electronic medical record database of the maternal-fetal unit of the two university hospitals included in our center.
Records were reviewed between January and April 2017 by a single reviewer (A.R.). The following data were extracted: patient characteristics (demographics, gravity, parity), early pregnancy BMI, pregnancy-associated hypertensive disorders, gestational diabetes mellitus (GDM), gestational age at delivery, mode of delivery, birth weight, BMI at delivery, gestational weight gain, perineal tears, postpartum hemorrhage, postpartum infection, thromboembolic complications, fetal distress in labor, Apgar score at 1 and 5 minutes, neonatal intensive care unit admission, congenital malformations, birth injury, and neonatal mortality. Early pregnancy BMI was calculated according to height and weight reported at the first prenatal visit. Gestational age was based on ultrasonography performed during the first trimester. Preterm delivery was defined as early (less than 32 completed weeks of gestation) or late (less than 37 completed weeks of gestation). Small-for gestational-age was defined as less than the 10th percentile and large-for-gestational-age (LGA) as greater than the 90th percentile using birth weight z-scores calculated with the formulas published by Dolberg et al16 on a similar population in Israel, adjusting for gestational age and the offspring's sex. Low birth weight was defined as less than 2,500 g and macrosomia as greater than 4,000 g. Postpartum hemorrhage was defined as bleeding 500 mL or greater after vaginal delivery and 1,000 mL or greater after cesarean delivery. Postpartum infection was defined as two measured maternal temperatures of 38°C at least 4 hours apart. Birth injury included shoulder dystocia, intraventricular hemorrhage, nerve palsy, scalp hematoma, and skeletal trauma. In addition, hemoglobin levels at the first prenatal visit as well as after discharge after delivery and the administration of intravenous iron supplementation were recorded. The decision regarding the administration of iron supplementation was at the discretion of the treating physician. Institutional review board approval waiving informed consent was obtained for this retrospective study from the Hadassah Medical Center Helsinki Committee.
Patient characteristics are described as proportions for categorical variables and medians and interquartile ranges for continuous variables without a normal distribution. Significance between groups was assessed by the χ2 test and Fisher exact test for categorical variables and the Mann–Whitney U test, a nonparametric test for continuous variables without a normal distribution. A two-sided P value <.05 indicated statistical significance.
One hundred nineteen patients who underwent laparoscopic sleeve gastrectomy were included in the study. The median time from surgery to conception was 508 days (range 372–954 days). These post–laparoscopic sleeve gastrectomy patients (post-LSG group) were compared with 119 matched patients in a control group. Baseline characteristics were comparable between the two groups (Table 1). Among the post–laparoscopic sleeve gastrectomy patients, the median preoperative BMI was 41.7 (interquartile range 39.9–44.4) and the early pregnancy BMI 28.9 (26.6–32.0; P=.001) with a median BMI loss of 31.5% (26.1%–37.5%).
The rate of GDM was significantly lower in the post-LSG group than in the control group (3.4% vs 17.6%, P=.001). The rate of cesarean delivery was lower in the post-LSG group as a result of a 50% reduction in the rate of cesarean deliveries performed during labor (10.1% vs 20.2%, P=.04) and a comparable rate of elective cesarean deliveries (25.2% vs 26.9%, P=.88). The indications for cesarean delivery did not differ between the groups (Table 2).
Median birth weight was significantly lower for the newborns of those in the post-LSG compared with the control parturients (median 3,030 vs 3,398 g, P=.001). Rates of macrosomia (0.8% vs 7.6%) and LGA neonates (1.7% vs 19.3%) were significantly lower for the post-LSG group than the control group (P=.02 and P=.001, respectively). The proportions of low-birth-weight (12.6% vs 4.2%, P=.03) and SGA neonates (14.3% vs 4.2%, P=.01) were higher for the post-LSG group than the control group (Table 3).
The median estimated blood loss was comparable between the groups (post-LSG 300 [200–500] vs control 350 [200–600] mL, P=.24). No thromboembolic events were encountered during pregnancy or the postpartum periods in either group.
Compared with the control group, in the post-LSG group, the median hemoglobin level was significantly lower at early pregnancy (12.6 vs 13.2 g/dL, P=.001), predelivery (11.5 vs 12.0 g/dL, P=.001), and after delivery (10.5 vs 10.8 g/dL, P=.002) (Table 2). In the study group, 17 (14.3%) received intravenous iron supplementation compared with one woman (0.8%) in the control group (P=.001).
In this retrospective case–control study, rates of several adverse pregnancy outcomes, including GDM, LGA neonates, macrosomia, and cesarean delivery during labor, were reduced among post–laparoscopic sleeve gastrectomy patients. On the other hand, they had a threefold increased risk for SGA neonates.
This study demonstrates a decreased risk of GDM and of macrosomic and LGA neonates among women who became pregnant after laparoscopic sleeve gastrectomy. This is in accordance with previous reports of bariatric surgery, which mainly involved patients undergoing laparoscopic Roux-en-Y gastric bypass.6–11 The findings are important because these beneficial effects were not consistently shown to occur after a purely restrictive procedure.12 The mechanisms implicated in these positive outcomes, although not well characterized, are postulated to involve caloric restriction, improved insulin sensitivity, and increased incretin effect.17 Incretin levels increase gradually from the second to third trimester and are correlated with lower fetal abdominal circumference and birth weight.18
Despite the aforementioned favorable effects, bariatric surgery was reported to negatively affect fetal growth, regardless of the degree of weight loss.6–10 The degree of weight loss before pregnancy in our cohort was similar to other studies among postbariatric surgery pregnant patients.6 Although laparoscopic adjustable gastric banding (ie, a restrictive procedure) was shown not be detrimentally associated with birth weight,11 risks of having a low-birth-weight and SGA neonates were increased in our cohort of post–laparoscopic sleeve gastrectomy (ie, a restrictive procedure) patients. Although this finding is consistent with studies that examined patients after Roux-en-Y gastric bypass (ie, malabsorptive procedure),6,11 it challenges the presumption that the observed risk of impaired fetal growth is the result of malabsorption and that purely restrictive procedures (eg, laparoscopic adjustable gastric banding, laparoscopic sleeve gastrectomy) would not pose such a risk.11 The observed risk of SGA in our cohort of patients undergoing laparoscopic sleeve gastrectomy suggests that the deleterious effect on fetal growth may involve factors other than malabsorption.
We report a significantly lower risk for cesarean delivery among post–laparoscopic sleeve gastrectomy patients, which was the result of a 50% reduction in the number of cesarean deliveries after a trial of labor. In contrast, several studies reported increased rates of cesarean delivery among postbariatric surgery patients with caregiver bias proposed to account for this finding.12,19,20 However, those studies included highly heterogeneous control groups without matching for patients' delivery history or differentiating between elective compared with in-labor cesarean delivery. Our approach matched study groups according to the number of previous cesarean deliveries performed and distinguished between in-labor and elective cesarean delivery rates. The potential beneficial effect of laparoscopic sleeve gastrectomy in regard to cesarean delivery should be confirmed in additional studies, because it may play a role in the decision process of a woman contemplating bariatric surgery before pregnancy.
Among women after laparoscopic sleeve gastrectomy, hemoglobin levels were lower in the first trimester of pregnancy as well as before delivery and in the immediate postpartum period. The lower hemoglobin levels found may be the result of a high rate of nutritional deficiencies, including iron, folate, and B12, coupled with low adherence to the recommended nutritional supplementation regimen, as was previously reported among patients undergoing laparoscopic sleeve gastrectomy.21 Previous studies demonstrated frequent micronutrient deficits among postbariatric surgery women throughout pregnancy, which were not totally eliminated, despite nutritional supplementation.22,23 We lacked data relevant to nutritional status and adherence to nutritional supplements in our cohort.
The retrospective design of this study raises the possibility of biases inherent to such investigations. Second, our study may lack sufficient statistical power to detect small but clinically relevant differences in infrequent outcomes. Moreover, women in the control group were matched by the major factors known to affect pregnancy outcomes; however, we could not exclude the possibility that additional unknown factors (ie, differential preconception care) could explain the differences observed between groups. Finally, our sample size was small compared with other studies and surgeries were performed at two institutions, which may limit the generalizability of our results, because of the relatively homogenous group of patients studied.
In conclusion, in this study, laparoscopic sleeve gastrectomy had an overall positive effect on maternal and neonatal outcomes by significantly reducing the risk for GDM, fetal macrosomia, and LGA neonates as well as in-labor cesarean deliveries. Nevertheless, laparoscopic sleeve gastrectomy was associated with an increased rate of low-birth-weight or SGA neonates. Future studies are warranted to confirm our findings, identify the optimal surgical-to-conception interval, formulate the optimal supplementation regimen, and better delineate the long-term outcomes of these newborns. As bariatric surgery, particularly laparoscopic sleeve gastrectomy, becomes increasingly prevalent among reproductive-aged women, understanding postsurgery pregnancy outcomes in this context is important for improving preconception counseling as well as antepartum care.
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