Abstract
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.
Key words
foetal morbidity - time of delivery - foetal acidosis