Prediction of postnatal abnormal coiling of the umbilical cord in gestational diabetes mellitus: a diagnostic accuracy study.

Objective: To investigate whether evaluations of antenatal umbilical coiling index (aUCI) could predict postnatal umbilical coiling index (UCI) (pUCI) in people with gestational diabetes mellitus (GDM) compared with normal pregnancy independent of maternal demographic and reproductive characteristics.Method: In this prospective study, 105 women with normal pregnancy, and 117 women with pregnancy complicated by GDM were recruited. Ultrasound scan of umbilical cord was performed at 18-23 and 37-41 weeks of gestation (WG). Evaluation of pUCI, as the reference standard, was performed within 24 hours after delivery.Findings: There was no significant relationship between aUCI and maternal demographic and reproductive characteristics. The mean for pUCI was 0.21 ± 0.12 in the GDM group, and 0.21 ± 0.09 in the normal pregnancy (p = .61). In the GDM group, a significant association was found between aUCI and pUCI categories (p = .004). The area under curve (AUC) was less than 0.5 for hypocoiling in both groups. For hypercoiling it was 0.84 ± 0.04 in the GDM group and 0.75 ± 0.06 in the normal pregnancy group (18-23 WG). In the GDM group the cutoff points that predict hypercoiling were 0.28 (18-23WG), and 0.21 (37-41WG). These were 0.35 (18-23WG), and 0.33 (37-41WG) in the normal pregnancy group. Diagnostic accuracy analysis revealed that in the GDM group, the sensitivity and specificity of hypercoiling for prediction of pUCI were 0.94 and 0.70 respectively at 18-23 WG.Conclusions: Antenatal hypercoiling at the second trimester of pregnancy strongly predict postnatal hypercoiling in pregnancies complicated by GDM.