More sunlight months during pregnancy gives newborns longer thighbones, study says

March 5, 2013, University College Dublin
More sunlight months during pregnancy (above 42 degrees north) gives newborns longer thighbones, study claims

(Medical Xpress)—The seasonal variation of sunlight in Ireland means newborns from Caucasian women who had more sunlight months during their pregnancy (April – Sep) are more likely to have longer thighbones, according to new research.

The findings published in are linked to the seasonal availability of sun [ sunlight] in northern latitude countries above 42 degrees north of the equator.

Our skin naturally produces vitamin D through exposure to the sun (UVB sunlight). But in northern latitude countries the skin's natural production of vitamin D essentially stops between November and March because of the lack of sun.

"While inside the womb, the developing baby is entirely dependent upon the maternal pool of vitamin D which is critical for the normal development of the baby's bones," says study author, Fionnuala McAuliffe, Professor of at the UCD School of Medicine and Medical Science, University College Dublin, and the National Maternity Hospital, Dublin.

The study involved 60 Caucasian pregnant women in Ireland. Thirty of the women (the winter group) delivered in Mar/April, while the other thirty (the summer group) delivered in Sep/Oct.

"Our findings showed low levels of vitamin D among nearly all the women in the study across both groups, ranging from 33% to 97% with a significant ," explains Professor McAuliffe.

"In turn, we identified a link between the mother's and baby's vitamin D level and the length of the baby's at 20 weeks, at 34 weeks, and the baby's length at birth."

"The women with lowest vitamin D levels in early pregnancy [the winter group] had babies with slightly shorter thighbones than those born from mothers with normal vitamin D levels [the summer group]," she adds.

The study by researchers from University College Dublin and the National Maternity Hospital, Ireland, funded by Health Research Board, measured the vitamin D levels in the mothers' blood in early pregnancy and again at 28 weeks. The study measured the cord blood vitamin D value which reflects the baby's vitamin D level.

Deficiencies in vitamin D during pregnancy can lead to reduced bone growth in babies before birth and poor bone development in early childhood.

According to Dr Jennifer Walsh, one of the researchers involved in the study, vitamin D supplements should be considered for pregnant women in Ireland and in other northern countries with poor dietary intakes of vitamin D, and in particular for women who will go through more of their during the darker months (Oct – March).

Previous scientific studies have shown that vitamin D supplementation during pregnancy has no adverse effects in women and their newborns.

A planned mixed diet including one to two portions of oily fish such as salmon or mackerel per week, more eggs, and fortified breakfast cereals can also help women increase their intake during pregnancy.

Explore further: Moms-to-be need more vitamin D, say experts

More information: Walsh, J. et al. Pregnancy in dark winters: Implications for fetal bone growth? Fertility and sterility 2013 Jan; 99 (1):206-11.

Related Stories

Moms-to-be need more vitamin D, say experts

July 7, 2011
Irish pregnant women have vitamin D intakes far below those recommended for the normal development of a child’s bones, according to research published in the European Journal of Clinical Nutrition.

Mother's vitamin D level linked to birth weight

December 10, 2012
Mothers' vitamin D levels at a gestation of 26 weeks or less were positively related to birth weight and head circumference, and, in the first trimester were negatively associated with risk of a baby being born small for ...

High Vitamin D levels in pregnancy may protect mother more than baby against MS

November 19, 2012
Pregnant women who have higher levels of vitamin D in their blood may have a lower risk of developing multiple sclerosis (MS) than women with lower levels, while their babies may not see the same protective effect, according ...

Pregnant women in Vancouver may not be getting enough vitamin D

August 11, 2011
Pregnant women taking prenatal supplements may not be getting enough vitamin D, shows a new Vancouver-based study led by the Child & Family Research Institute at BC Children's Hospital that was published in the Canadian Journal ...

Safe sun advice may help to raise vitamin D in Scottish mums-to-be

August 17, 2012
Too many women in Scotland are failing to follow current advice on vitamin D supplement use in pregnancy. This is leading to very low levels in some mothers and newborns, particularly in the winter months, and the problem ...

Recommended for you

Wine is good for you—to a point

January 18, 2018
The Mediterranean diet has become synonymous with healthy eating, but there's one thing in it that stands out: It's cool to drink wine.

Sleep better, lose weight?

January 17, 2018
(HealthDay)—Sleeplessness could cost you when it's time to stand on your bathroom scale, a new British study suggests.

Who uses phone apps to track sleep habits? Mostly the healthy and wealthy in US

January 16, 2018
The profile of most Americans who use popular mobile phone apps that track sleep habits is that they are relatively affluent, claim to eat well, and say they are in good health, even if some of them tend to smoke.

Improvements in mortality rates are slowed by rise in obesity in the United States

January 15, 2018
With countless medical advances and efforts to curb smoking, one might expect that life expectancy in the United States would improve. Yet according to recent studies, there's been a reduction in the rate of improvement in ...

Teens likely to crave junk food after watching TV ads

January 15, 2018
Teenagers who watch more than three hours of commercial TV a day are more likely to eat hundreds of extra junk food snacks, according to a report by Cancer Research UK.

Can muesli help against arthritis?

January 15, 2018
It is well known that healthy eating increases a general sense of wellbeing. Researchers at Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) have now discovered that a fibre-rich diet can have a positive influence ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.