Ramadan Fasting During Pregnancy Linked to Smaller Offspring

Steven Fox

February 25, 2013

Results from a new study of more than 1300 births show that mothers who were in utero during the observance of Ramadan delivered babies who were smaller and thinner and had smaller placentas than babies whose mothers were not in utero during Ramadan.

This study, carried out in Tunisia, was published online February 21 in American Journal of Human Biology.

For Muslims throughout the world, the month-long observance of Ramadan is an annual period of daytime fasting during which foods are traditionally only consumed at night. Even though pregnant women can choose to consume food during the day, most do not, preferring to share in the spiritual and social experiences of fasting with their families, the authors say.

In previous research, investigator S.H. Alwasel, PhD, Fetal Programming of Disease Research Chair, King Saud University, Saudi Arabia, and colleagues found that of babies born in Unizah, Saudi Arabia, those whose mothers had been in the second or third trimesters of their pregnancies during Ramadan differed from babies born to women who had not been pregnant during Ramadan. More specifically, babies born to women who were pregnant during Ramadan had reduced placental weight at birth without any change in birth weight.

The researchers have also previously shown that changes in the lifestyles of pregnant women during Ramadan can affect more than one generation.

Assessing a thousand newborn babies in Saudi Arabia, the researchers found that babies whose mothers had been in utero during Ramadan differed from those whose mothers had not been in utero during Ramadan. They also observed that boys were longer at birth and girls had shorter gestation periods.

"These were unexpected findings and require replication," the authors of the current study write.

With the aim of replicating their earlier findings, the researchers assessed body size at birth in 1321 babies (682 boys and 639 girls) born in Gafsa, a small city in Tunisia. All births took place from May 2011 to April 2012.

In the current study, the researchers again found differences between babies whose mothers had been in utero during Ramadan and those who had not.

"Babies whose mothers had been in utero during Ramadan were smaller and thinner, and had smaller placentas, than those whose mothers had not been in utero during Ramadan," they write. "After adjustment for sex, the babies were 93 g lighter (95% confidence interval, 32–153, P=0.003) than those whose mother had not been in utero during Ramadan; their mean ponderal index was 0.52 kg/m3 lower (0.24–0.79, P<0.001) and their placental weight was 21 g lower (5–37, P=0.01)."

The authors say that their findings did not differ by trimester of maternal exposure to Ramadan and that the findings were similar in boys and girls and in primiparous and multiparous mothers.

The investigators conclude that results of the new study provide further evidence that changes in lifestyle during Ramadan can have intergenerational effects.

The authors have disclosed no relevant financial relationships.

Am J Hum Biol. Published online February 21, 2013. Full text