A cohort study of maternal cardiometabolic risk factors and primary cesarean delivery in an integrated health system.

BACKGROUND: Maternal cardiometabolic risk factors (i.e., hyperglycemia, pre-existing hypertension and high body mass index) impact fetal growth and risk of having a cesarean delivery. However, the independent and joint contribution of maternal cardiometabolic risk factors to primary cesarean section is unclear. We aimed to elucidate the degree to which maternal cardiometabolic risk factors contribute to primary cesarean deliveries and whether associations vary by infant size at birth in an integrated health system. METHODS: A cohort study of 185,045 singleton livebirths from 2001 to 2010. Poisson regression with robust standard errors provided crude and adjusted relative risks (RR) and 95% confidence intervals (CIs) for cesarean delivery risk associated with risk factors. We then estimated the proportion of cesarean sections that could be prevented if the cardiometabolic risk factor in pregnant women were eliminated (the population-attributable risk [PAR]). RESULTS: In a single multivariable model, maternal cardiometabolic risk factors were independently associated with cesarean delivery: RR (95% CI) abnormal glucose screening 1.04 (1.01-1.08); gestational diabetes 1.18 (1.11-1.18) and pre-existing diabetes 1.60 (1.49-1.71); pre-existing hypertension 1.16 (1.10-1.23); overweight 1.27 (1.24-1.30); obese class I 1.46 (1.42-1.51); obese class II 1.73 (1.67-1.80); and obese class III 1.97 (1.88-2.07); adjusting for established risk factors, medical facility and year. The associations between maternal cardiometabolic risk factors and primary cesarean delivery remained among infants with appropriate weights for gestational age. The PARs were 17.4% for overweight/obesity, 7.0% for maternal hyperglycemia, 2.0% for pre-existing hypertension and 20.5% for any cardiometabolic risk factor. CONCLUSIONS: Maternal cardiometabolic risk factors were independently associated with risk of primary cesarean delivery, even among women delivering infants born at an appropriate size for gestational age. Effective strategies to increase the proportion of women entering pregnancy at an optimal weight with normal blood pressure and glucose before pregnancy could potentially eliminate up to 20% of cesarean deliveries.

Trends and racial and ethnic disparities in the prevalence of pregestational type 1 and type 2 diabetes in Northern California: 1996-2014.

BACKGROUND: Despite concern for adverse perinatal outcomes in women with diabetes mellitus before pregnancy, recent data on the prevalence of pregestational type 1 and type 2 diabetes mellitus in the United States are lacking. OBJECTIVE: The purpose of this study was to estimate changes in the prevalence of overall pregestational diabetes mellitus (all types) and pregestational type 1 and type 2 diabetes mellitus and to estimate whether changes varied by race-ethnicity from 1996-2014. STUDY DESIGN: We conducted a cohort study among 655,428 pregnancies at a Northern California integrated health delivery system from 1996-2014. Logistic regression analyses provided estimates of prevalence and trends. RESULTS: The age-adjusted prevalence (per 100 deliveries) of overall pregestational diabetes mellitus increased from 1996-1999 to 2012-2014 (from 0.58 [95% confidence interval, 0.54-0.63] to 1.06 [95% confidence interval, 1.00-1.12]; Ptrend <.0001). Significant increases occurred in all racial-ethnic groups; the largest relative increase was among Hispanic women (121.8% [95% confidence interval, 84.4-166.7]); the smallest relative increase was among non-Hispanic white women (49.6% [95% confidence interval, 27.5-75.4]). The age-adjusted prevalence of pregestational type 1 and type 2 diabetes mellitus increased from 0.14 (95% confidence interval, 0.12-0.16) to 0.23 (95% confidence interval, 0.21-0.27; Ptrend <.0001) and from 0.42 (95% confidence interval, 0.38-0.46) to 0.78 (95% confidence interval, 0.73-0.83; Ptrend <.0001), respectively. The greatest relative increase in the prevalence of type 1 diabetes mellitus was in non-Hispanic white women (118.4% [95% confidence interval, 70.0-180.5]), who had the lowest increases in the prevalence of type 2 diabetes mellitus (13.6% [95% confidence interval, -8.0 to 40.1]). The greatest relative increase in the prevalence of type 2 diabetes mellitus was in Hispanic women (125.2% [95% confidence interval, 84.8-174.4]), followed by African American women (102.0% [95% confidence interval, 38.3-194.3]) and Asian women (93.3% [95% confidence interval, 48.9-150.9]). CONCLUSIONS: The prevalence of overall pregestational diabetes mellitus and pregestational type 1 and type 2 diabetes mellitus increased from 1996-1999 to 2012-2014 and racial-ethnic disparities were observed, possibly because of differing prevalence of maternal obesity. Targeted prevention efforts, preconception care, and disease management strategies are needed to reduce the burden of diabetes mellitus and its sequelae.

Lactation and Progression to Type 2 Diabetes Mellitus After Gestational Diabetes Mellitus: A Prospective Cohort Study.

BACKGROUND: Lactation improves glucose metabolism, but its role in preventing type 2 diabetes mellitus (DM) after gestational diabetes mellitus (GDM) remains uncertain. OBJECTIVE: To evaluate lactation and the 2-year incidence of DM after GDM pregnancy. DESIGN: Prospective, observational cohort of women with recent GDM. (ClinicalTrials.gov: NCT01967030). SETTING: Integrated health care system. PARTICIPANTS: 1035 women diagnosed with GDM who delivered singletons at 35 weeks' gestation or later and enrolled in the Study of Women, Infant Feeding and Type 2 Diabetes After GDM Pregnancy from 2008 to 2011. MEASUREMENTS: Three in-person research examinations from 6 to 9 weeks after delivery (baseline) and annual follow-up for 2 years that included 2-hour, 75-g oral glucose tolerance testing; anthropometry; and interviews. Multivariable Weibull regression models evaluated independent associations of lactation measures with incident DM adjusted for potential confounders. RESULTS: Of 1010 women without diabetes at baseline, 959 (95%) were evaluated up to 2 years later; 113 (11.8%) developed incident DM. There were graded inverse associations for lactation intensity at baseline with incident DM and adjusted hazard ratios of 0.64, 0.54, and 0.46 for mostly formula or mixed/inconsistent, mostly lactation, and exclusive lactation versus exclusive formula feeding, respectively (P trend = 0.016). Time-dependent lactation duration showed graded inverse associations with incident DM and adjusted hazard ratios of 0.55, 0.50, and 0.43 for greater than 2 to 5 months, greater than 5 to 10 months, and greater than 10 months, respectively, versus 0 to 2 months (P trend = 0.007). Weight change slightly attenuated hazard ratios. LIMITATION: Randomized design is not feasible or desirable for clinical studies of lactation. CONCLUSION: Higher lactation intensity and longer duration were independently associated with lower 2-year incidences of DM after GDM pregnancy. Lactation may prevent DM after GDM delivery. PRIMARY FUNDING SOURCE: National Institute of Child Health and Human Development.

Prevalence of cervical insufficiency in polycystic ovarian syndrome.

BACKGROUND: Pregnant women with polycystic ovarian syndrome (PCOS) experience a greater rate of adverse obstetrical outcomes compared with non-PCOS women. We examined the prevalence and incidence of cervical insufficiency (CI) in a community cohort of pregnant women with and without PCOS. METHODS: A retrospective cohort study was conducted within a large integrated health care delivery system among non-diabetic PCOS women with second or third trimester delivery during 2002-2005 (singleton or twin gestation). PCOS was defined by Rotterdam criteria. A non-PCOS comparison group matched for delivery year and hospital facility was used to estimate the background rate of CI. Women were designated as having new CI diagnosed in the index pregnancy (based on cervical dilation and/or cervical shortening) and prior CI based on prior diagnosis of CI with prophylactic cerclage placed in the subsequent pregnancy. RESULTS: We identified 999 PCOS women, of whom 29 (2.9%) had CI. There were 18 patients with new CI and 11 with prior CI having prophylactic cerclage placement; four CI patients had twin gestation. In contrast, only five (0.5%) non-PCOS women had CI: two with new CI and three with prior CI. The proportion of newly diagnosed incident CI (1.8 versus 0.2%) or prevalent CI (2.9 versus 0.5%) was significantly greater for PCOS compared with non-PCOS pregnant women (both P < 0.01). Among PCOS women, CI prevalence was particularly high among South Asians (7.8%) and Blacks (17.5%) compared with Whites (1%) and significantly associated with gonadotropin use (including in vitro fertilization). Overall, the PCOS status was associated with an increased odds of prevalent CI pregnancy (adjusted odds ratio 4.8, 95% confidence interval 1.5-15.4), even after adjusting for maternal age, nulliparity, race/ethnicity, body mass index and fertility treatment. CONCLUSION: In this large and ethnically diverse PCOS cohort, we found that CI occurred with a higher than expected frequency in PCOS women, particularly among South Asian and Black women. PCOS women with CI were also more likely to have received gonadotropin therapy. Future studies should examine whether natural and hormone-altered PCOS is a risk factor for CI, the role of race/ethnicity, fertility drugs and consideration for heightened mid-trimester surveillance in higher risk subgroups of pregnant women with PCOS.