Antenatal risk prediction of shoulder dystocia: influence of diabetes and obesity: a multicenter study.

Abstract

To estimate the risk of shoulder dystocia (SD) in pregnancies with/without maternal diabetes or obesity; to identify antenatal maternal and fetal ultrasound-derived risk factors and calculate their contributions. A multicenter retrospective analysis of 13,428 deliveries in three tertiary hospitals (2014-2017) with fetal ultrasound data ≤ 14days prior to delivery (n = 7396). singleton pregnancies in women ≥ 18years old; vertex presentation; vaginal delivery at ≥ 37weeks of gestation. Estimated fetal weight (EFW) and birth weight (BW) were categorized by steps of 250g. To evaluate risk factors, a model was performed using ultrasound data with SD as the dependent variable. Diabetes was present in 9.3%; BMI ≥ 30kg/m2 in 10.4% and excessive weight gain in 39.8%. The total SD rate was 0.9%, with diabetes 2.0% and with obesity 1.9%. These increased with BW 4250-4499g compared to 4000-4249g in women with diabetes (12.1% vs 1.9%, P = 0.010) and without (6.1% vs 1.6%, P < 0.001) and at the same BW threshold for women with obesity (9.6% vs 0.6%, P = 0.002) or without (6.4% vs 1.8%, P < 0.001). Rates increased similarly for EFW at 4250g and for AC-HC at 2.5cm. Independent risk factors for SD were EFW ≥ 4250g (OR 3.8, 95% CI 1.5-9.4), AC-HC ≥ 2.5cm (OR 3.1, 95% CI 1.3-7.5) and diabetes (OR 2.2, 95% CI 1.2-4.0). HC/AC ratio, obesity, excessive weight gain and labor induction were not significant. Independent of diabetes, which remains a risk factor for SD, a significant increase may be expected if the EFW is ≥ 4250g and AC-HC is ≥ 2.5cm.