Related Factors for Abnormal Umbilical Cord Insertion: A Preliminary Study Based on Two Regional Tertiary Hospitals in Japan.

Objective: We elucidated maternal background, perinatal complications and outcomes as potential related factors for abnormal umbilical cord insertion (ACI) -velamentous and marginal- based on data from two tertiary perinatal hospitals in Japan.

Materials and methods: The subjects were 3,741 women with singleton pregnancies who delivered at ≥ 22 weeks' gestation in Kurume University Hospital and St. Mary's Hospital, Kurume, Japan from January 2013 to December 2015. They were divided into two groups, with and without ACI. Related factors were extracted from the medical registry database of the perinatal committee in the Japan Society of Obstetrics and Gynecology. Random Forest and stepwise logistic regression models were employed to evaluate their impact on ACI.

Results: Related factors for ACI in terms of maternal background and perinatal complications and outcomes were: pre-pregnancy smoking habit (adjusted odds ratio, OR, 3.38; 95% confidence interval, CI, 2.20-5.20; P < 0.0001); conception using assisted reproductive technology (adjusted OR, 2.00; 95% CI, 1.11-3.60; P = 0.021); placenta previa (adjusted OR, 4.74; 95% CI, 2.06-10.90; P < 0.0001); fetal growth restriction (adjusted OR, 2.43; 95% CI, 1.49-3.97; P < 0.0001); and non-reassuring fetal status during labor (adjusted OR, 2.74; 95% CI, 1.71-4.38; P < 0.0001).

Conclusion: This was a preliminary study attempting to elucidate related factors for ACI in a Japanese population. However, further large-scale studies are needed in Japan.