Sunshine in early pregnancy can reduce premature birth risk

We know that being in the sun lowers blood pressure and improves heart health – but latest research suggests this isn’t due to vitamin D, which we get from sunlight, and is actually a direct effect of sunshine on the skin. A new study from our Centre for Maternal and Fetal Health in Edinburgh shows that getting more sunlight while pregnant can reduce the chance of placenta problems associated with premature birth and baby loss.

Understanding premature birth

Premature birth is the leading cause of neonatal loss (when a baby dies in the first 28 days of life) in the UK, so we desperately need to understand and prevent it. The Office for National Statistics records the rates of premature birth every year, and we can see there are seasonal patterns, but we haven’t been able to explain them. 

We know that sun exposure has risks and benefits for human health but its effects on pregnancy and premature birth are unknown. The Tommy's team in Edinburgh decided to change this, by combining postcode-specific weather records from 2000-2010 with maternity care data from 397,370 mothers and 556,376 babies born at 24+ weeks of pregnancy.

Findings newly published by Frontiers in Reproductive Health show that mothers with more sun available in their first trimester were less likely to give birth prematurely – regardless of other things that could raise their risk, like age and smoking status. Sun exposure in the second trimester wasn’t shown to make any difference to premature birth risk, although previous research in China found this could improve babies’ chances of being born a healthy size and weight.

Preventing premature birth

As our findings suggest that early pregnancy seems to be a key opportunity for mothers to guard against premature birth simply by getting out in the sunshine, this could help shape the advice given to families during pregnancy. 

We’ll be doing lots more work to better understand the relationship between sunshine and premature birth, and hopefully use this knowledge to develop new preventative therapies; for example, the team is already looking at whether artificial light can have similar effects on pregnancy health, in case this could benefit parents who live in places with limited sunlight.

“It’s often unclear why babies are born early, but our new research suggests that sunlight during early pregnancy can reduce the risk – so mums-to-be should try spending more time in the sunshine, while our researchers keep working to unpick this relationship and see if light therapies could be used to prevent premature birth.” - Tommy’s CEO Jane Brewin

60,000 babies are born prematurely each year and the reasons often have nothing to do with the mother’s lifestyle, but we know there are some things we can do to reduce the risk, so communicating these latest research findings as widely as possible is a vital part of our mission to save babies’ lives.

Find out more about our ground-breaking premature birth research