Aims To evaluate the interaction effects of gestational diabetes ( GDM ) with obesity on perinatal outcomes. Methods A population‐based cohort study in Sweden excluding women without pre‐gestational diabetes with a singleton birth between 1998 and 2012. Logistic regression was performed to evaluate the potential independent associations of GDM and BMI with adverse perinatal outcomes as well as their interactions. Main outcome measures were malformations, stillbirths, perinatal mortality, low Apgar score, fetal distress, prematurity and Erb's palsy. Results Some 1,294,006 women were included, with a GDM prevalence of 1% ( n = 14,833). The rate of overweight/obesity was 67.7% in the GDM ‐group and 36.1% in the non‐ GDM ‐group. No significant interaction existed. Offspring of women with GDM had significantly increased risk of malformations, adjusted odds ratio ( aOR ) 1.16 (95% confidence intervals 1.06–1.26), prematurity, aOR 1.86 (1.76–1. 98), low Apgar score, aOR 1.36 (1.10–1.70), fetal distress, aOR 1.09 (1.02–1.16) and Erb's palsy aOR 2.26 (1.79–2.86). No risk for stillbirth or perinatal mortality was seen. Offspring of overweight ( BMI 25–29.9 kg/m 2 ), obese ( BMI 30–34.9 kg/m 2 ) and severely obese women ( BMI ≥ 35.0 kg/m 2 ) had significantly increased risks of all outcomes including stillbirth 1.51 (1.40–1.62) to 2.85 (2.52–3.22) and perinatal mortality 1.49 (1.40–1.59) to 2.83 (2.54–3.15). Conclusions There is no interaction effect between GDM and BMI for the studied outcomes. Higher BMI and GDM are major independent risk factors for most serious adverse perinatal outcomes. More effective pre‐pregnancy and antenatal interventions are required to prevent serious adverse pregnancy outcomes among women with either GDM or high BMI .

AimTo analyse the impact of overweight and obesity on the risk of adverse maternal outcomes and fetal macrosomia in pregnancies of women treated for severe gestational diabetes.MethodsThis was a population‐based cohort study including all singleton pregnancies in Sweden without pre‐existing diabetes in the period 1998–2012. Only mothers with an early‐ pregnancy BMI of ≥ 18.5 kg/m² were included. Logistic regression analysis was used to determine odds ratios with 95% CIs for maternal outcomes and fetal growth. Analyses were stratified by maternal gestational diabetes/non‐gestational diabetes to investigate the impact of overweight/obesity in each group.ResultsOf 1 249 908 singleton births, 13 057 were diagnosed with gestational diabetes (1.0%). Overweight/obesity had the same impact on the risks of caesarean section and fetal macrosomia in pregnancies with and without gestational diabetes, but the impact of maternal BMI on the risk of preeclampsia was less pronounced in women with gestational diabetes. Normal‐weight women with gestational diabetes had an increased risk of caesarean section [odds ratio 1.26 (95% CI 1.16–1.37)], preeclampsia [odds ratio 2.03 (95% CI 1.71–2.41)] and large‐for‐gestational‐age infants [odds ratio 2.25 (95% CI 2.06–2.46)]. Risks were similar in the overweight group without gestational diabetes, caesarean section [odds ratio 1.34 (1.33–1.36)], preeclampsia odds ratio [1.76 (95% CI 1.72–1.81)], large‐for‐gestational‐age [odds ratio 1.76 (95% CI 1.74–1.79)].ConclusionsMaternal overweight and obesity is associated with similar increments in risks of adverse maternal outcomes and delivery of large‐for‐gestational‐age infants in women with and without gestational diabetes. Obese women with gestational diabetes are defined as a high‐risk group. Normal‐weight women with gestational diabetes have similar risks of adverse outcomes to overweight women without gestational diabetes.

Background: The optimal criteria to diagnose gestational diabetes mellitus (GDM) remain contested. The Swedish National Board of Health introduced the 2013 WHO criteria in 2015 as a recommendation for initiation of treatment for hyperglycaemia during pregnancy. With variation in GDM screening and diagnostic practice across the country, it was agreed that the shift to new guidelines should be in a scientific and structured way. The aim of the Changing Diagnostic Criteria for Gestational Diabetes (CDC4G) in Sweden (www.cdc4g.se/en) is to evaluate the clinical and health economic impacts of changing diagnostic criteria for GDM in Sweden and to create a prospective cohort to compare the many long-term outcomes in mother and baby under the old and new diagnostic approaches. Methods: This is a stepped wedge cluster randomised controlled trial, comparing pregnancy outcomes before and after the switch in GDM criteria across 11 centres in a randomised manner. The trial includes all pregnant women screened for GDM across the participating centres during January-December 2018, approximately two thirds of all pregnancies in Sweden in a year. Women with pre-existing diabetes will be excluded. Data will be collected through the national Swedish Pregnancy register and for follow up studies other health registers will be included. Discussion: The stepped wedge RCT was chosen to be the best study design for evaluating the shift from old to new diagnostic criteria of GDM in Sweden. The national quality registers provide data on the whole pregnant population and gives a possibility for follow up studies of both mother and child. The health economic analysis from the study will give a solid evidence base for future changes in order to improve immediate pregnancy, as well as long term, outcomes for mother and child. Trial registration: CDC4G is listed on the ISRCTN registry with study ID ISRCTN41918550 (15/12/2017

Objective: To evaluate whether pregnancy is associated with increased risk for small bowel obstruction after laparoscopic gastric bypass surgery. Background: Small bowel obstruction is a common and feared long-term complication to laparoscopic gastric bypass surgery that may be more common during pregnancy. It is unclear if the risk truly increases during pregnancy. Methods: Women, 18 to 55 years, operated with a primary laparoscopic gastric bypass procedure from 2010 until 2015 were identified through the Scandinavian Obesity Surgery Registry (n = 25,853). Through record-linkage to the Medical Birth Registry, the National Patient Registry, and review of hospital charts, information on pregnancy periods and outcome were obtained. The main outcome was operation due to small bowel obstruction after the laparoscopic gastric bypass procedure. Results: Pregnancy was associated with increased risk for small bowel obstruction following laparoscopic gastric bypass surgery (incidence rates 46.5, 95% CI 38.0–56.9/1000 person-years, vs 20.9 95% CI 19.9–22.0; adjusted-HR 1.72, 95% CI 1.39–2.12, P < 0.001). While no excess risk was observed during the first trimester, the second (adjusted-HR 1.67, 95% CI 1.17–2.39, P = 0.005) and third (adjusted-HR 2.69, 95% CI 2.02–3.59, P < 0.001) conferred increased risk. The incidence rate of small bowel obstruction during pregnancy was 42.9 (95% CI 32.4–57.0/1000 person-years) among women for whom the mesenteric defects had been closed during the primary procedure, and 53.2 (95% CI 38.9–72.8/1000 person-years) for women in whom they had been left open. Conclusion: Pregnancy is associated with increased risk for small bowel obstruction after laparoscopic gastric bypass surgery during the second and third trimesters.

Aim To assess whether incidence of maternal and neonatal outcomes for women with or without gestational diabetes mellitus (GDM) have changed over time. Methods Population-based cohort study in Sweden including all singleton pregnancies over the period 1998-2012. GDM was diagnosed following Diabetic Pregnancy Study Group 1991 criteria. Poisson regression or negative binomial regression was used to model yearly relative change in numbers of cases and incidence of the outcomes with 95% confidence intervals (CI), and yearly absolute change in birthweight z-score. Results The study included 1 455 667 pregnancies. The number of pregnancies increased over time and the overall prevalence of GDM was 1%. For women with GDM there was a significantly decreasing trend in incidence per year for large for gestational age (LGA) (0.986, 95% CI 0.975 to 0.996), birthweight z-score (À0.012, 95% CI À0.017 to À0.007) and birth trauma (0.937, 95% CI 0.907 to 0.968). The trend for small for gestational age (SGA) among women with GDM increased by an odds ratio per year (1.016, 95% CI 1.002 to 1.029). No significant interaction tests for maternal characteristics were found. Trends in outcomes for women without diabetes were similar to those for women with GDM. Conclusions This study shows that there were improvements in pregnancy outcomes for women with GDM between 1998 and 2012, although the incidence of SGA increased. Improvements followed similar trends in the background population. Inequalities in obstetric outcomes between women with GDM and those without have continued unchanged over 15 years, suggesting that new management strategies are required to reduce this gap.