Associations between maternal circulating 25-hydroxyvitamin D concentration and birth outcomes-Mode of delivery and episiotomy rate: A prospective cohort study.
Inmaculada Gómez-Carrascosa, María L Sánchez-Ferrer, Julian J Arense-Gonzalo and 5 others
PMID 33991181WHAT IT FOUND
In 117 pregnant women, first-trimester vitamin D levels showed no link with delivery mode or episiotomy.
Low or insufficient vitamin D was frequent, but the study did not test supplementation or prove vitamin D changes birth outcomes.
Key findings
01The adjusted odds ratio for instrumental delivery was 2.14 and for episiotomy was 0.79 in the highest versus lowest vitamin D quartile, and neither was significant.
02The adjusted odds ratios for primary Caesarean section and Caesarean section for other causes were 1.30 and 2.50 in the highest versus lowest vitamin D quartile, and neither was significant.
03Forty-one per cent of women had vitamin D below 20 ng/ml and 47% had levels between 20 and 29 ng/ml.
STILL TO COME
How it was doneWhat they foundWhat it means for RNs
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What it does not show
Only 117 women were followed until birth, after 31 dropouts, 7 miscarriages and 10 deliveries at another hospital, so the study may have been too small to detect a real association. Vitamin D was measured once in the first trimester, so levels later in pregnancy were not captured. The study was observational, so it cannot show that vitamin D caused any delivery outcome. Physical activity, tobacco and alcohol were self-reported, so misreporting could affect the results. Women who did not attend the first-trimester ultrasound were not represented, and the study was done in one hospital with Caucasian singleton pregnancies.
Declared interests
The authors declared no competing interests.
The easy way to misread this
Do not conclude that vitamin D deficiency causes different birth outcomes or that supplementation will change delivery mode or episiotomy. This was an observational study of 117 women that found no significant associations and did not test supplementation.