The following is a summary of “Predicting primary cesarean delivery in pregnancies complicated by gestational diabetes mellitus,” published in the NOVEMBER 2023 issue of Obstetrics and Gynecology by Ramos, et al.
Prediction models have emerged as valuable tools for shared decision-making between clinicians and patients by offering quantitative estimates of individual risk for critical clinical outcomes. Gestational diabetes mellitus (GDM) poses an increased risk of primary cesarean delivery (CD) during pregnancy. While suspected fetal macrosomia is a recognized risk factor, comprehensive tools considering multiple risk factors are lacking. For a study, researchers sought to develop and internally validate a multivariable model for estimating the risk of intrapartum primary CD in pregnancies complicated by GDM, thereby facilitating shared decision-making. They developed and internally validated a multivariable model to estimate the risk of intrapartum primary CD in pregnancies complicated by GDM undergoing a trial of labor.
A cohort of patients with GDM, derived from a large National Institutes of Health-funded medical record study, was identified, delivering singleton live-born infants at ≥34 weeks of gestation at a tertiary care center between January 2002 and March 2013. Exclusion criteria included previous CD, contraindications to vaginal delivery, scheduled primary CD, and known fetal anomalies. Clinical variables available in the third trimester associated with an increased CD risk in GDM were considered predictors. A logistic regression model was constructed using stepwise backward elimination. Model performance was evaluated for goodness of fit and discrimination and internally validated using bootstrapping.
Of 3,570 pregnancies meeting the criteria, 987 (28%) had a primary CD. The final model included eight variables significantly associated with CD, covering aspects such as fetal size, polyhydramnios, maternal age, body mass index, hemoglobin A1C levels, parity, insulin treatment, and preeclampsia. The model demonstrated satisfactory calibration (Hosmer-Lemeshow test, P=.862) and discrimination (area under the receiver operating characteristic curve, 0.75, 95% CI 0.74–0.77). Internal validation confirmed consistent discriminatory ability. Stratification by parity showed effective model performance among both nulliparous and multiparous patients.
The study proposed a clinically pragmatic model using readily available third-trimester information to predict intrapartum primary CD risk in GDM pregnancies. The model’s reasonable reliability may offer valuable quantitative data for patients to comprehend their individual CD risk based on preexisting and acquired factors, contributing to informed decision-making.
Source: ajog.org/article/S0002-9378(23)00371-X/fulltext
