gms | German Medical Science

Introduction: Ramadan fasting is prevalent among pregnant Muslim women around the world. This form of intermittent fasting can cause nutritional deprivation, resulting in impaired fetal development. However, the association between Ramadan during pregnancy and offspring health along the entire life course has not yet been fully established. Mixed evidence on visible health impairments at birth has led previous reviews to the conclusion that prenatal exposure to maternal Ramadan fasting is not significantly associated with offspring health. Yet, fetal programming research indicates that prenatal exposures can cause long-term structural and physiological changes that adversely affect offspring health. We reconcile this conundrum by combining a rigorous meta-analysis on offspring health at birth with an all-encompassing literature synthesis on offspring health at later life stages, augmented by an extensive risk-of-bias assessment.

Methods: We performed a systematic literature review and meta-analysis on original, peer-reviewed articles published until November 2, 2023. These articles were sourced from PubMed, EMBASE, Web of Science, and EconLit databases. Included were studies that evaluated health outcomes in individuals with prenatal Ramadan exposure, compared to an unexposed Muslim control group. Each study was individually evaluated for bias risk using a pre-established scheme. The overall quality of evidence was appraised using the GRADE system. Random-effects meta-analyses were conducted for outcomes analyzed in at least three primary studies.

Results: We identified 31 publications fulfilling the eligibility criteria for the qualitative synthesis, of which 18 studies were included in meta-analyses. Not all newborn and one childhood outcome could be meta-analyzed. Among newborns, prenatal Ramadan exposure was not associated with effects on birth weight (mean difference (MD) -3 grams (95% CI -18 11) or the likelihood of prematurity (percentage point difference (PPD) 0.19 (95% CI -0.11 0.49)). The probability that a newborn is male was reduced (PPD -0.14 (95% CI -0.28 -0.00)). In childhood, the exposed performed poorer on cognitive outcomes such as standardized tests in school. Height growth among the exposed was reduced, and this pattern was already visible at ages below 5 (height-for-age z-score MD -0.03 (95% CI -0.06 -0.00)). Childhood mortality rates were increased in low-income contexts. In adulthood, the prenatally exposed had impaired outcomes on various dimensions, including an increased likelihood of having disabilities, as well as chronic diseases or their symptoms, and worse labor market outcomes.

Conclusion: We produced a nuanced life-course assessment of the effects of Ramadan during pregnancy, which is essential to provide pregnant women and healthcare professionals with objective evidence on the offspring health effects of intermittent fasting during pregnancy. Our synthesis of existing research demonstrates that Ramadan during pregnancy is associated with adverse health effects among the offspring in childhood and especially adulthood, despite an absence of observable health effects at birth. Not all health effects may apply to all Muslim communities, which are diverse in their backgrounds and behaviors. Notably, moderating factors like daytime activity levels, and dietary habits outside fasting hours have hardly been considered. It is imperative for future research to address these aspects.

The authors declare that they have no competing interests.

The authors declare that an ethics committee vote is not required.