PDF Ebook The Effects of Maternal Fasting During Ramadan on Birth and Adult Outcomes
We use the Islamic holy month of Ramadan as a natural experiment for evaluating the short and long-term effects of fasting during pregnancy. Using Michigan natality data we show that in utero exposure to Ramadan among Arab births results in lower birthweight and reduced gestation length. Preconception exposure to Ramadan is also associated with fewer male births. Using Census data in Uganda we also find that Muslims who were born nine months after Ramadan are 22 percent (p =0.02) more likely to be disabled as adults. Effects are found for vision, hearing, and especially for mental (or learning) disabilities. This may reflect the persistent effect of disruptions to early fetal development. We find no evidence that negative selection in conceptions during Ramadan accounts for our results. Nevertheless, caution in interpreting these results is warranted until our findings are corroborated in other settings.
Pregnant women are especially susceptible to the timing of nutrition. A set of biochemical changes known as “accelerated starvation” (Metzger et al., 1982) can occur with meal-skipping during pregnancy, but not outside of pregnancy. Whether “accelerated starvation” impacts fetal development and birth out-comes has not been established.
The burgeoning literature on the “fetal origins” hypothesis suggests that adult health may also respond to maternal fasting while in utero. 2 The strongest observational evidence for fetal origins comes from famine episodes,3 wherein prolonged nutritional deprivation is plausibly uncorrelated with other determinants of adult health (Stein et al., 1975). However, famines are relatively rare, and the external validity of these studies for non-famine episodes is unclear. We therefore consider a relatively mild, temporary, and common disruption to prenatal nutrition – that occasioned by meal-skipping or fasting.
We use the holy month of Ramadan —one of the five “pillars” of Islam as a natural experiment in maternal fasting during pregnancy. Muslims are encouraged to fast during the lunar month of Ramadan. Fasting includes abstaining from eating during daylight as well as avoiding drinking beverages (and sex). Certain persons are automatically exempted from fasting: “children, those who are ill or too elderly, those who are traveling, and women who are menstruating, have just given birth, or are breast feeding” (Esposito, 2003). In contrast, pregnant women must request a special dispensation from fasting and are generally required to make up the days later when they may be the only family member fasting. Evidence from surveys suggests that the majority (e.g. 70-90 percent) of pregnant women observe the fast.
The fact that Ramadan follows a lunar calendar implies that its observance shifts forward 11 days every Julian year. This “drift” together with its month-long duration implies that more than three quarters of pregnancies overlap with Ramadan. Over a period of 32 Julian years, Ramadan completes a full circuit of the western calendar. This feature permits the separate identification of Ramadan from seasonal effects on health (Doblhammer & Vaupel, 2001). In contrast to previous epidemiological studies, we can also evaluate which month of pregnancy is associated with the largest Ramadan effect.
Our initial analysis of health outcomes utilizes natality data from Michigan – home to a large Muslim population. We observe pregnancy and birth outcomes that potentially could be affected by fasting, such as birthweight, gestation length and the sex of the child. Although we do not know the religion of the mother we infer Muslim status based on ancestry.5 We find that birthweight is significantly lower among infants of Arab descent who were exposed to fasting during Ramadan in utero compared to those whose fetal development did not overlap with Ramadan. The effects are stronger when Ramadan falls during the summer and the diurnal fast is longer. For example, our estimates imply that birthweight would be 50 grams lighter among those whose first month of gestation completely overlapped with Ramadan during the summer solstice. The effects on those who actually fast are likely to be larger to the extent that not all pregnant Muslim women fast and we include Arabs who are non-Muslim. We also find significant effects of fasting in reducing gestation length (although this only accounts for a small portion of the overall birthweight effects.) Importantly, we find no comparable effects for non-Arabs of Ramadan’s timing.
Download
PDF Ebook The Effects of Maternal Fasting During Ramadan on Birth and Adult Outcomes
Posted in :
