A new study produced further evidence that a fever during pregnancy can cause fetal damage. The study authors also offered suggestions regarding how to reduce the risk if a pregnant woman develops a fever. The findings were published online on February 24 in the journal Pediatrics by researchers at the University of Southern Denmark (Esbjerg, Denmark), and the University of Copenhagen (Copenhagen, Denmark).
The study authors note that fever during pregnancy has been suspected to harm the developing fetus. However, despite that notion, the medical literature does not contain any systematic analyses of the available evidence that evaluated the impact of maternal fever on health outcomes in the offspring. Therefore, the focus of their study was to systematically review evidence from epidemiologic studies on adverse health outcomes of the children in relation to exposure to maternal fever during pregnancy.
The researchers conducted a systematic review and a meta-analysis (a compilation of data from a number of studies to add additional validity to a theory. They conducted systematic searches in PubMed, Web of Science, and the Cochrane Library. Cohort and case-control studies that examined the health outcomes of prenatal fever exposure in humans were included in the study. (Cohort studies are those that are comprised of individuals with similar characteristics. Case-control studies are a type of observational study in which two existing groups differing in outcome are identified and compared on the basis of some supposed causal attribute (in this case, fever). Excluded were studies that lacked direct reference to fever, studies in selected populations (e.g., preterm births), and studies published before 1990.
The study authors found that the literature review supported an increased risk of adverse offspring health among children whose mothers experienced a fever during pregnancy. The strongest evidence was found for neural tube defects (brain and spinal cord; e.g., spina bifida), congenital heart defects, and oral clefts (cleft palate); the meta-analyses revealed an increased risk ranging between a 1.5- and nearly 3-fold increased risk with fever exposure during the first trimester (first three months of pregnancy). They did not find strong evidence of a dose–response relationship (i.e., a higher risk with a higher fever); however, some evidence existed that antipyretic (fever-lowering) medications may have a protective effect when used in relation to febrile episodes.
The authors concluded that they found substantial evidence to support the concept that maternal fever during pregnancy may negatively affect offspring health. They noted that the harmful effects appeared to involver both short- and longer-term health outcomes; however, for several outcomes, the evidence was insufficient to determine that an association existed.
Take home message:
This study notes that pregnant women should exercise extreme caution, particularly during the first three months of pregnancy, regarding exposure to an infection. If an infection and fever occurs, taking antipyretic medications may reduce the risk of fetal harm. Antipyretic medications include: non-steroidal anti-inflammatory agents (NSAIDs) such as ibuprofen (Motrin) and naproxen (Aleve, Anaprox); aspirin; and acetaminophen (Tylenol). Among, the antipyretics, aspirin appears to have the best safety record. If you develop a fever during pregnancy, it is extremely important to keep well hydrated as this can result in lowering of the fever.