Foetal Morbidity Depending on the Day and Time of Delivery

Introduction It is known that perinatal mortality is increased with births at night and at the weekend. The aim of the study was to investigate whether there is also an association between the time of delivery (weekday, night, weekend) and perinatal morbidity. Material and Methods All births at Hannover Medical College between 2000 and 2014 were included in a retrospective data analysis. Multiple births, primary sections, severe foetal malformations and intrauterine deaths were not included. A 5-minute Apgar score ≤ 5 and cord arterial pH < 7.10 were defined as perinatal morbidity. Besides the time of delivery, different variables that are regarded as risk factors for increased perinatal morbidity were studied. Univariate logistical regression analysis was performed, followed by multivariate analysis. Results 18 394 deliveries were included in the study. Pathological prepartum Doppler, medical induction of labour and delivery at night and/or at the weekend significantly increased the probability of an Apgar score ≤ 5 after 5 minutes. The probability that a child will have cord arterial pH < 7.1 post partum is significantly increased with a BMI > 25 before pregnancy, primiparity, medical induction of labour, peripartum administration of oxytocic agents, when the delivery took place at night and weekend combined, but also when the delivery took place at night or at the weekend/on a public holiday. Multivariate regression analysis showed that a time of delivery at night and/or at the weekend or on a public holiday is not a prognostic factor for a 5-minute Apgar score ≤ 5 (p = 0.2377) but is a prognostic factor for cord arterial pH < 7.1 (p = 0.0252). Conclusion The time of delivery at night or at the weekend/on a public holiday increases the risk for cord arterial pH < 7.1 by ~ 30% compared with delivery on a weekday. However, the time of delivery at night or at the weekend/on a public holiday does not increase the risk for the baby of having a 5-minute Apgar score ≤ 5.