A study in Germany finds that a high-fat diet can moderate negative associations between fasting during pregnancy and low birthweight.
Research has previously shown statistical associations between fasting while pregnant during the Muslim month of Ramadan and adverse health outcomes in offspring.[1-8] Now, a study published by German scientists in the journal PLoS ONE finds that negative impacts of fasting on birthweight may be moderated by increasing dietary fat content during the nonfasting hours.[9]
“Our study shows that it seems essential to ensure that women who do choose to fast have sufficient calorie intake to minimize negative impacts on birth weight,” says Fabienne Pradella, a postdoctoral researcher in statistics and econometrics at Johannes Gutenberg-University in Mainz, Germany. “Interestingly, the negative effects on birthweight disappear among women who switched to a high-fat diet during Ramadan, presumably because such a diet makes it easier to consume a sufficient amount of calories during this month in which meal frequency is reduced.”
“While this seems good news to pregnant women who wish to fast,” adds Pradella, “it should be noted that we do not yet know whether a high-fat diet also helps avoid long-run health effects on the offspring. In other words, we do not yet know sufficiently how the consumption of specific (macro)nutrients and food groups may mitigate the long-run effects of fasting on the child. Until we do, the advice is to be careful with fasting during pregnancy.”
Methodology and results
Pradella and her colleagues at Johannes Gutenberg-University retrospectively surveyed 326 Muslim women who gave birth in Mainz, Germany, and whose pregnancies overlapped with the month of Ramadan in 2017. They also obtained, with consent, their hospital data on neonatal birthweight and length of gestation. The surveys asked the women about their fasting during Ramadan, diets, sleep patterns, employment status prior to parental leave, highest educational attainment, country of birth, nulliparity, and length of stay in Germany. Data were also collected on prepregnancy BMI, pregnancy risk factors (smoking, alcohol consumption, drug use, and consanguinity), and awareness of pregnancy during Ramadan.
Among the 326 surveyed women, 30% fasted anywhere from 3 to 29 days during Ramadan 2017. 47% of the fasting group fasted at least 20 days, with the first trimester overlapping with Ramadan in 42% of the fasting women.
The study found that fasting during pregnancy was associated with reduced birthweight (−158.19 g; 95% CI, −300.83 to −15.55). Children of mothers who fasted during the first trimester had significantly lower birthweight than the children of mothers who did not fast despite the overlap of their first trimester with Ramadan (−352.92 g; 95% CI, −537.38 to −168.46). The effects of fasting 10-19 days and 20-29 days were similar, while the association of birthweight with fasting 3-9 days was not significant.
Importantly, the negative fasting-birthweight association only appeared for women who reduced high-fat content or did not change their intake of high-fat content foods during Ramadan.
Sleep reduction and sweet food consumption were not significantly associated with birthweight.
“Our research, with its relatively small sample size, will not answer all questions regarding how diet during non-fasting hours may influence how Ramadan during pregnancy affects the child,” says Pradella. “But, given the accumulating evidence on adverse health effects of fasting during pregnancy, we believe it is an important start that hopefully leads to much follow-up research.”
Context and respect are important
Ramadan falls at different times of the year, as it follows the lunar calendar. Ramadan 2017 occurred during the months of May and June, when fasting hours were exceedingly long in Germany, reaching up to 18 hours a day. The daily number of hours fasted varies depending on geographical location and the seasons in which Ramadan happens to fall. Lifestyle patterns and food consumption are also dependent on cultural differences and can vary widely.
“According to most Islamic interpretations, pregnant women are exempt from fasting if they have concerns about their health or the health of their baby,” says Pradella. “Ramadan fasting during pregnancy is a highly sensitive issue, as many women who observe this practice have deep-rooted religious motivations. Our survey results revealed that 73% of fasting women consider it an expression of their faith, even during pregnancy. It is crucial for healthcare providers to acknowledge and respect these religious beliefs… It is worth noting that Ramadan fasting is not the only form of intermittent fasting observed during pregnancy, and other practices, such as skipping breakfast or dieting are also common.”
Mohammed Sattar, a general practitioner at Woodhouse Medical Practice in Leeds, UK, who was not involved in the study, says that the structured interview approach has its limitations, and a real-time diary, rather than a retrospective questionnaire, could be preferable. The researchers acknowledge this limitation in their study, but say it is, “impossible to recruit a representative sample of women in all stages of pregnancy who are willing to fill out such diaries during an upcoming Ramadan; especially when the sample should be large enough to conduct multiple linear regression analysis on their linked birth outcomes.”
Consultant endocrinologist Nazim Ghouri, honorary associate professor at the University of Glasgow, UK, adds that hyperemesis gravidarum during the first trimester could have a compounding effect that needs to be taken into consideration. Ghouri, who was not involved in the study, would also have been interested to see if it was people from higher socioeconomic backgrounds with greater awareness of higher-energy foods who consumed higher-fat meals, thus mitigating the low birthweight outcome. He commented on the fact that many studies on fasting during pregnancy and its negative outcomes on offspring are association studies and cannot indicate causality.
Guiding patients
“Deciding whether a patient who is pregnant can fast must be done on an individual basis, taking into account the maternal health, risks of pregnancy to date, and reviewed regularly,” says Sattar. “Often a multidisciplinary team approach is helpful for considering viewpoints from all specialists involved in the care. Risk stratifying those who want to fast is important. Ultimately our aim would be to support the patient and reach a shared understanding for the safest outcome.”
Ghouri has put together, with colleagues, a compendium of evidence on fasting in Ramadan with various health conditions. “One of the things we do within our guidelines is ask you to think about the individual as a whole, not just the medical side, but the socio-psychological factors at play, their age, frailty and previous experience of fasting. Past performance may indicate what might happen in the future…The compendium includes general principles and disease-specific guidance with risk stratification and a traffic-light-based system. So we might say fasting could be considered safe, we advise against it, or strongly advise not to fast, for example.”
The German research team is now exploring the role of medical practitioners in the decision-making process of pregnant Muslims considering the fast. “Our results suggest that talking about Ramadan with one’s healthcare professional can significantly impact a pregnant woman’s choice to fast during Ramadan,” says Pradella. “It is therefore crucial for practitioners to be aware of the timing of Ramadan, so that they can proactively discuss the issue with their Muslim patients.”
Ramadan 2023 is expected to run from around March 23 to April 21, depending on the sighting of the new moon.
