The effects of prenatal exposure to Ramadan on stature during childhood and adolescence: Evidence from the Indonesian Family Life Survey.

Many pregnant Muslim women fast during the Muslim holy month of Ramadan. A number of studies have reported negative life outcomes in adulthood for children who were prenatally exposed to Ramadan. However, other studies document minimal to no impact on neonatal indicators. Using data from the Indonesian Family Life Survey consisting of 45,246 observations of 21,723 children born to 9771 mothers, we contribute to the current discussion on prenatal exposure to Ramadan by examining the effects on stature (height-for-age Z-scores, weight-for-age Z-scores, and body-mass-index-for-age Z-scores: HAZ, WAZ, and BAZ, respectively) from early childhood to late adolescence (0-19 years of age). We introduce an objective mother's religiosity indicator to improve the intention-to-treat estimations. Children were classified into three groups based on their mother's religion-religiosity: religious Muslims, less-religious Muslims, and non-Muslims. Using cluster-robust mother fixed-effects, we found negative effects on stature for children born to religious Muslim mothers. The effects were age-dependent and timing-sensitive. For example, children born to religious Muslim mothers were shorter in late adolescence (15-19 years of age) compared to their unexposed siblings if they were prenatally exposed in the first trimester of pregnancy (HAZ difference = -0.105 SD; p-val. <0.05). Interestingly, we found positive effects on stature for exposed less-religious Muslim children that peak in early adolescence (10-14 years of age) and negative effects on stature for exposed non-Muslim children that occur only in early childhood (0-4 years of age). We nuance our discussion of health and socioeconomic factors to explain these surprising results.