Roux-en-Y Gastric Bypass Increases Glycemic Excursions During Pregnancy and Postpartum: A Prospective Cohort Study

A systematic review on clinical practice guidelines for managing pregnancy following metabolic-bariatric surgery

OBJECTIVE

The ongoing pandemic of obesity is associated with an increase of weight loss surgeries in women of reproductive age. This study was conducted to review clinical practice guidelines (CPGs) for managing pregnancy following metabolic-bariatric surgery.

METHODS

We conducted a comprehensive literature search of all CPGs that covered the management of pregnancy following metabolic-bariatric surgery, 2010 through 2022, and that were published in English. Two authors independently scored the quality and usefulness of CPGs using the Appraisal of Guidelines for Research and Evaluation II tool (AGREE II).

RESULTS

From a total of 20 CPGs, consistent recommendations included the following: 1) contraception with long-acting reversible contraceptives before surgery until the optimal time of pregnancy; 2) nutritional care by a dietitian; 3) considering gastrointestinal discomforts during pregnancy as a potential surgical complication; and 4) modified screening for gestational diabetes instead of glucose tolerance tests preventing post-bariatric hypoglycemia. There was a lack of uniformity concerning surgery-to-conception interval and dose of supplements, as well as research gaps regarding the surgical type, mental health, delivery type, breastfeeding, neonatal care, and weight retention.

CONCLUSIONS

All recommendations for managing pregnancy after metabolic-bariatric surgery were deemed clinically useful. Although consistent recommendations should be implemented, inconsistencies should be the focus of research.

The association of higher offspring early-childhood weight gain with prepregnancy metabolic and bariatric surgery

OBJECTIVE

The objective of this study was to assess maternal gestational outcomes and offspring growth trajectories following prepregnancy metabolic and bariatric surgery (MBS) compared with non-MBS controls.

METHODS

Single-center deliveries between January 2020 and March 2023 with prepregnancy Roux-en-Y gastric bypass (herein referred to as "bypass"), sleeve gastrectomy (herein referred to as "sleeve"), and non-MBS controls were included. Offspring growth trajectories were compared with the World Health Organization child growth standards. Linear mixed models assessed MBS-bypass and MBS-sleeve offspring weight, length, and BMI trajectories with a prepregnancy BMI 27 to 37 kg/m2 and propensity score-matched controls.

RESULTS

The study included 440 participants with prepregnancy MBS (MBS-bypass, 185; MBS-sleeve, 225; 76% Hispanic/Latino) and 13,434 non-MBS controls. Gestational weight gain and gestational diabetes mellitus were similar, whereas hypertensive disorders of pregnancy were more common after MBS. The post-MBS offspring had lower birth weight but higher weight gain at 24 months (sleeve, +1.4 kg [95% CI: 1.0-1.9]; bypass, +0.5-0.7 kg [95% CI: 0.0-1.2]) compared with non-MBS groups. Male children had higher weight gain than females. The post-MBS-sleeve but not the post-MBS-bypass offspring had higher BMI z scores.

CONCLUSIONS

The higher early-life weight gain and sex differences in the post-MBS-sleeve group compared with the post-MBS-bypass group provide a window toward elucidating pathways to mitigate intergenerational metabolic risk transfer.

Pregnancy and offspring outcomes after prepregnancy bariatric surgery

BACKGROUND

Bariatric surgery is internationally performed as a treatment option in obesity to achieve significant and sustained weight loss. There is an increasing number of women having pregnancies after bariatric surgery with mixed maternal and fetal outcomes, with a limited number of large, matched studies.

OBJECTIVE

This study aimed to describe the type of prepregnancy bariatric surgery, analyze maternal, pregnancy, and offspring outcomes relative to matched women, and assess the impact of prepregnancy bariatric surgery on fetal growth, particularly the proportions of small for gestational age and large for gestational age infants.

STUDY DESIGN

A cross-sectional, matched study was performed using a statewide hospital and perinatal data register. A total of 2018 births of 1677 women with prepregnancy bariatric surgery were registered between 2013 and 2018. Of those, 1282 were included and analyzed, matched in a 1:10 ratio for age, parity, smoking status, and body mass index to women without bariatric surgery. The first singleton pregnancy following bariatric surgery for each woman was used for analysis. Pregnancy and neonatal outcomes based on International Statistical Classification of Diseases and Related Health Problems, Tenth Revision, Australian Modification, and neonatal birth records were analyzed. Multivariable logistic regression was used to estimate the association between small for gestational age and large for gestational age infants and prepregnancy bariatric surgery.

RESULTS

Of the 1282 women, 93% had undergone laparoscopic sleeve gastrectomy. Among women with prepregnancy bariatric surgery compared with matched women, offspring had lower absolute birthweight (3223±605 vs 3418±595 g; P<.001), and a lower rate of large for gestational age infants (8.6% vs 14.1%; P<.001) and a higher rate of small for gestational age infants (10.7% vs 7.3%; P<.001) were found. Offspring of mothers with prepregnancy bariatric surgery were more likely to be born preterm (10.5% vs 7.8%; P=.007). Fewer women with previous bariatric surgery were diagnosed with gestational diabetes mellitus (15% vs 20%; P<.001) or pregnancy-induced hypertension (3.7% vs 5.4%; P=.01). In the adjusted model, prepregnancy bariatric surgery was associated with lower risk of large for gestational age (odds ratio, 0.54; 95% confidence interval, 0.44-0.66) and higher risk of small for gestational age infants (odds ratio, 1.78, 95% confidence interval, 1.46-2.17).

CONCLUSION

These data suggest that prepregnancy bariatric surgery was associated with a reduction in several obesity-related pregnancy complications at the expense of more preterm births and small for gestational age offspring.

Gestational Weight Gain Following Metabolic Bariatric Surgery: A Scoping Review

Metabolic bariatric surgery remains the most effective and durable treatment for severe obesity. Women of reproductive age represent the largest demographic group undergoing these procedures. Metabolic bariatric surgery can have both beneficial and adverse effects on pregnancy outcomes. One of the most common adverse effects is fetal growth restriction. To mitigate these adverse effects, it is crucial to explore lifestyle modifications aimed at promoting a healthy pregnancy. Modifiable factors during pregnancy after metabolic bariatric surgery include the amount of gestational weight gain. The aim of this comprehensive review is to provide an overview of what is known about gestational weight gain in pregnancy after bariatric metabolic surgery. This review is focused on the two most performed procedures: sleeve gastrectomy and Roux-en-Y gastric bypass.

Gestational Diabetes Risk and Low Birth Weight After Metabolic Bariatric Surgery: a Complex Interplay to be Balanced

INTRODUCTION

Metabolic bariatric surgery (MBS) is known to improve the obstetric outcomes of women with obesity and to prevent gestational diabetes (GD). To what extent does MBS decreases GD, without incurring at additional risks is a matter of concern.

METHODS

A retrospective case-control study to compare the pregnancy outcomes of women previously submitted to MBS to those of age and preconception body mass index (PC BMI) matched non-operated controls.

RESULTS

Pregnancies of women after MBS (n = 79) and matched controls (n = 79) were included. GD was significantly less frequent after MBS (7.6% vs. 19%; p = 0.03). Fasting blood glucose (76.90 ± 0.77 vs 80.37 ± 1.15 mg/dl, p < 0.05; 70.08 ± 1.34 vs. 76.35 ± 0.95 mg/dl; p < 0.05, first and second trimesters respectively) and birth weight (2953.67 ± 489.51 g vs. 3229.11 ± 476.21 g; p < 0.01) were significantly lower after MBS when compared to controls. The occurrence of small-for-gestational-age (SGA) was more frequent after MBS (22.8% vs. 6.3%; p < 0.01), but no longer significant after controlling for smoking habits (15.5% vs. 6%, p = 0.14). There were no significant differences in gestational weight gain, prematurity rate nor mode of delivery between groups.

CONCLUSION

MBS was associated with a lower prevalence of GD than observed in non-operated women with the same age and BMI. After controlling for smoking, this occurred at the expense of a lower birth weight. Our data reinforces the hypothesis that MBS has body weight independent effects on glucose kinetics during pregnancy with distinctive impacts for mother and offspring, which need to be balanced.

Pregnancy Outcomes After Bariatric Surgery: Importance of Maternal Ferritin on Birth Weight

PURPOSE

The risks carried by pregnancy after bariatric surgery (BS) include small-for-gestational age (SGA) newborn and prematurity. However, the underlying mechanisms are not yet fully understood in pregnant women after BS.

MATERIAL AND METHODS

This single-center retrospective observational cohort study includes all women with a first and single pregnancy after BS who completed at least one clinical and biological nutritional assessment during pregnancy between 2010 and 2016. The quarterly biological assessment comprised blood count, ferritin, calcium, 25OH vitamin D, parathyroid hormone, fasting glucose, albumin, prealbumin, vitamin A, vitamin B12, folic acid, and zinc.

RESULTS

Among 120 pregnancies analysed, two-thirds underwent gastric bypass (Roux-en-Y and one-anastomosis) and one-third a restrictive procedure (adjustable gastric band or sleeve gastrectomy). The median [Q1-Q3] preoperative BMI was 43.8 [41.1-47.7] kg/m2 and the mean age at pregnancy was 32.6 ± 5.3 years. Weight loss and time from surgery to pregnancy were 35.1 ± 15.4 kg and 2.9 [1.3-4.5] years, respectively. Ten women (8%) gave birth prematurely, and 22 newborns (19%) were SGA. Univariate analysis shows that ferritin was significantly higher in mothers with SGA than in those without SGA (35.5 [22.3-69.5] vs. 15 [10-32] ng/ml) at third trimester of pregnancy. Women who received pre-pregnancy nutritional assessment seemed less likely to give birth to a SGA newborn (32% vs. 54%, p = 0.07).

CONCLUSION

Iron supplementation should be carefully prescribed and closely monitored during pregnancy in women who have undergone BS.

Glucose levels measured with continuous glucose monitoring in uncomplicated pregnancies

INTRODUCTION

To characterize glucose levels during uncomplicated pregnancies, defined as pregnancy with a hemoglobin A1c <5.7% (<39 mmol/mol) in early pregnancy, and without a large-for-gestational-age birth, hypertensive disorders of pregnancy, or gestational diabetes mellitus (ie, abnormal oral glucose tolerance test).

RESEARCH DESIGN AND METHODS

Two sites enrolled 937 pregnant individuals aged 18 years and older prior to reaching 17 gestational weeks; 413 had an uncomplicated pregnancy (mean±SD body mass index (BMI) of 25.3±5.0 kg/m2) and wore Dexcom G6 continuous glucose monitoring (CGM) devices throughout the observed gestational period. Mealtimes were voluntarily recorded. Glycemic levels during gestation were characterized using CGM-measured glycemic metrics.

RESULTS

Participants wore CGM for a median of 123 days each. Glucose levels were nearly stable throughout all three trimesters in uncomplicated pregnancies. Overall mean±SD glucose during gestation was 98±7 mg/dL (5.4±0.4 mmol/L), median per cent time 63-120 mg/dL (3.5-6.7 mmol/L) was 86% (IQR: 82-89%), median per cent time <63 mg/dL (3.5 mmol/L) was 1.8%, median per cent time >120 mg/dL (6.7 mmol/L) was 11%, and median per cent time >140 mg/dL (7.8 mmol/L) was 2.5%. Mean post-prandial peak glucose was 126±22 mg/dL (7.0±1.2 mmol/L), and mean post-prandial glycemic excursion was 36±22 mg/dL (2.0±1.2 mmol/L). Higher mean glucose levels were low to moderately associated with pregnant individuals with higher BMIs (103±6 mg/dL (5.7±0.3 mmol/L) for BMI ≥30.0 kg/m2 vs 96±7 mg/dL (5.3±0.4 mmol/L) for BMI 18.5-<25 kg/m2, r=0.35).

CONCLUSIONS

Mean glucose levels and time 63-120 mg/dL (3.5-6.7 mmol/L) remained nearly stable throughout pregnancy and values above 140 mg/dL (7.8 mmol/L) were rare. Mean glucose levels in pregnancy trend higher as BMI increases into the overweight/obesity range. The glycemic metrics reported during uncomplicated pregnancies represent treatment targets for pregnant individuals.

Beyond Weight Loss: A Comprehensive Review of Pregnancy Management following Bariatric Procedures

The increasing prevalence of bariatric surgery among women of childbearing age raises critical questions about the correct management of pregnancy following these procedures. This literature review delves into the multifaceted considerations surrounding pregnancy after bariatric surgery, with a particular focus on the importance of preconception counselling, appropriate nutrition assessment, and the necessity of correct folic acid supplementation. Key areas of investigation include nutrient absorption challenges, weight gain during pregnancy, and potential micronutrient deficiencies. Examining the relationship between bariatric surgery and birth defects, particularly heart and musculoskeletal issues, uncovers a twofold increase in risk for women who underwent surgery before pregnancy, with the risk emphasized before folic acid fortification. In contrast, a nationwide study suggests that infants born to mothers with bariatric surgery exhibit a reduced risk of major birth defects, potentially associated with improved glucose metabolism. In addition, this review outlines strategies for managing gestational diabetes and other pregnancy-related complications in individuals with a history of bariatric surgery. By synthesizing existing literature, this paper aims to provide healthcare providers with a comprehensive framework for the correct management of pregnancy in this unique patient population, promoting the health and well-being of both mother and child.

Increased glycemic variability in pregnant women with Roux-en-Y gastric bypass compared with sleeve gastrectomy

INTRODUCTION

Bariatric surgery is associated with adverse pregnancy outcomes such as reduced birth weight and premature birth. One possible mechanism for this is increased glycemic variability (GV) which occurs after bariatric surgery. The objective of this study was to compare the effect of Roux-en-Y gastric bypass (RYGB) versus vertical sleeve gastrectomy (SG) on GV during pregnancy and to investigate the relationships of GV, type of bariatric surgery and maternal and neonatal outcomes.

RESEARCH DESIGN AND METHODS

Fourteen pregnant women after RYGB and 14 after SG were investigated with continuous glucose monitoring in their second or third trimester in this observational study carried out as part of routine clinical care.

RESULTS

Pregnant women with RYGB had similar mean interstitial glucose values but significantly increased indices of GV and a lower %time in range 3.9-7.8 mmol/L (70-140 mg/dL), compared with SG.

CONCLUSIONS

Pregnant women who have undergone RYGB have greater GV during pregnancy compared with those who have undergone SG. Further research is needed to establish the relationship between GV and pregnancy outcomes to determine the preferred bariatric operation in women of reproductive age, and whether interventions to reduce GV might improve outcomes.

Medical and Psychological Aspects of Pregnancy in Women with Obesity and after Bariatric Surgery

Chronic diseases are potential risk factors for pregnancy duration and neonatal outcomes. This narrative review aimed to summarize the research results on the specifics of pregnancy in women with obesity and after bariatric surgery. PubMed and Google Scholar databases were searched. Systematic reviews, meta-analyses, clinical trials, and references to identified articles from the last ten years (2013-2023) were included. Ultimately, 107 literature items were qualified. It has been shown that women with obesity planning pregnancy should reduce their body weight because obesity is a risk factor for adverse obstetric and neonatal outcomes. Bariatric surgery effectively reduces excessive body weight and the health risks in women with obesity during pregnancy and their offspring. However, at least a year interval between surgery and conception is recommended. An interdisciplinary medical team should provide patient care during pregnancy with knowledge and skills related to people after bariatric surgery. Due to the increased risk of mental disorders, especially depression, it is necessary to constantly monitor the mental state of women and provide psychological support and education on a healthy lifestyle during pregnancy and the postpartum period.

Post-bariatric hypoglycaemia diagnosed during pregnancy

Summary

There is a scarcity of literature relating to post-bariatric hypoglycaemia (PBH) in pregnancy. Recurrent hyperglycaemia and hypoglycaemia can have significant consequences for both the mother and the developing fetus. We describe a case of a young pregnant woman who was diagnosed with symptomatic PBH in the second trimester of pregnancy using continuous glucose monitoring (CGM) 3 years after Roux-en-Y gastric bypass (RYGB) surgery. Instigating a low glycaemic index and complex carbohydrate diet significantly improved the patient's glycaemic excursions. Given that this condition is likely underdiagnosed as a complication of RYGB surgery, a greater awareness of this complication is needed. Patients should be adequately consented pre-operatively for this relatively frequent late surgical complication to enable patients to identify symptoms of this condition at an early stage and seek medical treatment.

Learning points

PBH is an important diagnosis in patients post-RYGB surgery, particularly in women of childbearing age when consequences of both hyperglycaemia and hypoglycaemia during pregnancy can adversely affect both mother and the fetus. Adverse outcomes of recurrent hypoglycaemia to the fetus can include small for gestational age, intrauterine growth restriction and possible impairment of beta cell function. Providing adequate carbohydrate intake to allow growth of the fetus during pregnancy while also attempting to resolve both hyperglycaemia and hypoglycaemia associated with PBH by reducing the intake of simple carbohydrates and high glycaemic index foods can prove challenging. Patients should be adequately consented for late complications of RYGB surgery such as PBH in order to allow early recognition of symptoms and enable prompt treatment.

Comment: pregnancy after bariatric surgery - achievements and open questions

Bariatric surgery confers potential advantages for obese patients, but also risks for pregnancy. Perinatal outcomes may be varying between surgical procedures. This topic was recently addressed by a systematic review in BMC Pregnancy and Childbirth. This commentary will discuss the scientific background and implications for future research.

Use of Continuous Glucose Monitoring in Patients Following Bariatric Surgery: A Scoping Review

The objective of this scoping review was to summarize the emerging literature on the use of continuous glucose monitoring (CGM) in post-bariatric surgery patients, with a focus on its features (e.g., device, mode, and accuracy), as well as purposes and outcomes of utilization. Three databases (PubMed, EMBASE, and Web of Science) were searched to obtain relevant studies. Results suggested that most studies used CGM for 3-7 days under blinded mode. Accuracy data were available in only one study, which reported a mean absolute relative difference of 21.7% for Freestyle Libre. The primary applications of CGM were for elucidating glucose patterns and assessing glycemic treatment outcomes. No study has tested the effect of CGM as an intervention strategy to enhance glucose control.