27 Mar Vitamin D: good or bad for pregnant women?
Recent studies on vitamin-D levels in pregnancy appear to contradict each other. One, from the University of Bristol, said maternal vitamin-D levels don’t affect the child’s bone health. A second, from the University of Calgary, said low levels cause pregnancy complications.
A third study, from 2018, looked at vitamin D and IVF treatment. It found better live-birth rates when patients had enough vitamin D in their systems after IVF cycles. So should pregnant women monitor their vitamin-D levels? Read on.
Vitamin D is a hot topic. We know it keeps maternal bones and teeth in good shape by optimising calcium and phosphate levels. Doctors tell us, particularly in winter (when sunlight, a valuable source of vitamin D, is in short supply) that we should increase our vitamin-D intake.
4,000 women and children took part in the Bristol study. The mothers had their vitamin-D levels checked each trimester. Their offspring were analysed after their ninth birthday. The researchers found no link between mother and child in relation to the vitamin. Not even if the mother smoked – a common way to deplete vitamin D in the body.
Don’t throw away that oily fish yet. The Calgary study went the other way. Researchers looked at previous studies and concluded that low vitamin D during pregnancy stores up trouble. It may increase the risk of gestational diabetes, pre-eclampsia and low birth weight.
Both studies were not conclusive. Each said more research was needed to pinpoint how much vitamin D, if any, should be recommended to pregnant mothers, and if supplements were routinely necessary. UK guidelines say pregnant women should take a 10-mcg vitamin-D supplement. Other countries suggest different amounts, or none at all. The US says five.
With studies on pregnancy and vitamin-D presenting different data, we’re all confused. So let’s turn to the WHO. It recently changed its advice. Pregnant women, it says, should not take vitamin-D supplements. Instead, better nutrition and sunlight should be the focus. Read the full WHO guidance here.
If you’re planning IVF, good vitamin-D monitoring seems sensible. A study from Italy said it doubled pregnancy rates after fertility treatment and made better quality embryos that were more likely to implant. So let’s hear it for vitamin D. But absorbed naturally, not from supplements. If you’re planning fertility treatment, have a read of our perfect IVF diet tips.