Emergency Caesarean 2X more likely if less than 12 ng of Vitamin D – Aug 2020

Late Pregnancy Vitamin D Deficiency is Associated with Doubled Odds of Birth Asphyxia and Emergency Caesarean Section: A Prospective Cohort Study

Maternal and Child Health Journal (2020)
Hanna Augustin, Sinead Mulcahy, Inez Schoenmakers, Maria Bullarbo, Anna Glantz, Anna Winkvist & Linnea Bärebring

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Objectives
The aim of this prospective cohort study was to investigate the associations between maternal vitamin D status in late pregnancy and emergency caesarean section (EMCS) and birth asphyxia, in a population based sample of women in Sweden.

Methods
Pregnant women were recruited at the antenatal care in Sweden and 1832 women were included after exclusion of miscarriages, terminated pregnancies and missing data on vitamin D status. Mode of delivery was retrieved from medical records. EMCS was defined as caesarean section after onset of labour. Birth asphyxia was defined as either 5 min Apgar score < 7 or arterial umbilical cord pH < 7.1. Serum was sampled in the third trimester of pregnancy (T3) and 25-hydroxyvitamin D (25OHD) was analysed by liquid chromatography tandem mass spectrometry. Vitamin D deficiency was defined as 25OHD < 30 nmol/L, and associations were studied using logistic regression analysis and expressed as adjusted odds ratios (AOR).

Results
In total, 141 (7.7%) women had an EMCS and 58 (3.2%) children were born with birth asphyxia. Vitamin D deficiency was only associated with higher odds of EMCS in women without epidural anaesthesia (AOR = 2.01, p = 0.044). Vitamin D deficiency was also associated with higher odds of birth asphyxia (AOR = 2.22, p = 0.044).

Conclusions for Practice
In this Swedish prospective population-based cohort study, vitamin D deficiency in late pregnancy was associated with doubled odds of birth asphyxia and with EMCS in deliveries not aided by epidural anaesthesia. Prevention of vitamin D deficiency among pregnant women may reduce the incidence of EMCS and birth asphyxia. The mechanism behind the findings require further investigation.

Significance
What is already known on this subject?
Poor maternal vitamin D status is suggested as a risk factor of delivery by caesarean section and birth asphyxia. However, studies are few and the data are contradictory.

What this study adds
In this population-based cohort study, maternal vitamin D deficiency doubled the odds of delivering a baby with birth asphyxia and of delivery by emergency caesarean section in women without epidural anaesthesia. The interaction between vitamin D deficiency and epidural anaesthesia might explain disparate results in previous studies, and should be considered in future studies.