The fasting month of Ramadan: Does intermittent fasting of pregnant women influence the risk for preterm birth?

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Fasting during Ramadan is a valuable experience for Muslims all over the world. Even though it is not compulsory for pregnant women to participate in fasting, many choose to do so. However, the question arises as to whether abstaining from food and water throughout the day could have an impact on the well-being of the unborn child. To answer this question, fourteen studies from seven countries were reviewed, involving more than 2,800 expectant mothers. The results show that Ramadan fasting influences neonatal weight and other parameters of foetal health. However, most of the effects, including the risk for preterm birth, were found to be non-significant. This indicates that fasting during Ramadan is not harmful for the baby overall, and that the decision to participate in Ramadan fasting should therefore be left to the mother.

Ramadan is a month focusing on prayer, community, and reflection for all Muslims around the world. Central to this is the Ramadan fasting (RF), which is a form of intermittent fasting in which no food or water is consumed from sunrise to sunset. The abstinence from water during the fasting period makes RF more intense compared to other forms of intermittent fasting. While RF is obligatory for healthy Muslims, breastfeeding mothers and pregnant women are exempt from fasting and can decide for themselves whether they feel fit enough to participate or not. The Muslim population makes about ¼ of the world’s population, and accordingly many pregnant women face the question if they can participate in RF without harming the foetus. This concern arises from the fact that an adequate supply of nutrients is important to meet the needs of both mother and foetus, and neonatal weight is a direct indicator of the foetus’ wellbeing.

A total of 14 studies from seven countries examined the topic and the results were analysed in an overall review. The 2,889 participating mothers lived in Turkey, Iran, Lebanon, Pakistan, the UK, the Netherlands, and Saudi Arabia.


Ramadan fasting has a significant influence on birth weight

Several different measurements indicate foetal health and can be used to analyse the effects of RF on the unborn child. One indicator is neonatal weight. The findings varied in the different studies examined, but the overall effect showed a significantly lower birth weight in fasting mothers. The amniotic fluid index (AFI), a standardised indicator of foetal well-being, also showed a significant effect. The combination of dehydration during RF, longer daytimes, and temperatures above 36°C led to a reduction of the AFI in fasting mothers. Further significant correlations were found between RF and foetal femur length and RF and lower biparietal diameter assessing foetal size in fasting mothers.

The results on gestational age at delivery were contradictory but insignificant altogether. When analysing the impact on preterm birth (PTB), only one study showed a slightly increased incidence of PTB when the mother was fasting. The increase was not statistically significant and all other studies that examined PTB reported no association, leading to the redeeming conclusion that RF has no effect on the likelihood of PTB.

Various other measures showed no significant impact of RF on foetal health, including foetal body weight, length, head circumference, and abdominal circumference of the infant. The biophysical profile also did not change for fasting mothers, nor did the foetal movements, breathing movements, tone, amniotic fluid volume or the Apgar Score.


Fasting for expectant mothers is not harmful to neonatal health overall

Although RF affects foetal growth, it is not associated with poorer neonatal health. The negative associations between fasting and foetal well-being were stronger when the mother fasted during the second or third trimester of her pregnancy. Furthermore, all associations between RF and reduced health were predominantly found in lower quality studies, which supports the evidence that fasting is safe for pregnant women. Thereafter, current scientific evidence shows that fasting during Ramadan is not harmful to the foetus and can be practiced by pregnant women. The decision to fast should therefore be made by the pregnant woman herself, in consultation with her doctor, who will take her individual health status into account. The wellbeing of the foetus depends more on the type of food the mother eats during the fast-breaking period of Ramadan.


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Ful list of authors: Andrew Khai Weyn Ong, Anne Li Yee, Adrian Jing Hong Fong, Valliammai Jayanthi Thirunavuk Arasoo and Amutha Ramadas