Although I love every moment in the NICU, in an ideal world neonatal nurses would be out of a job. Congenital defects, genetic disorders, prematurity, etc. would never come to pass. However, this is not the case. All we can do is try to give our patients the best care possible and use new research to continually better our practice. In my opinion, knowledge of good prenatal care and the will to educate pregnant mothers may prevent the occupation of some of our cribs. That is why my ears perked up when I saw the article, “Really? Babies Conceived in the Spring Are More Likely to Be Premature” on The New York Times website (1).
According to the author, there is a large amount of medical literature discussing seasonal patterns and the risk of chronic conditions. Despite the quantity of such research, the method of approach is often flawed. Nevertheless, a study published in Proceedings of the National Academy of Sciences may be the largest and most persuasive connection between seasonal gestation and conditions, specifically conception in the spring and preterm birth (2).
The article, “Within-mother analysis of seasonal patterns in health at birth,” discusses the seasonality of gestation of about 1.4 million children. The same mothers were followed over time to eliminate differences in maternal characteristics. This accounts for socioeconomic differences of mothers who are likely to conceive in different months according to individual status. The researchers claim that women who conceive in May are 10% more likely to experience preterm birth. They attribute this pattern to the spike in influenza cases in January and February when the mothers are nearing full term. Influenza has been studied and shown to cause adverse birth outcomes, possibly due to the inflammatory response which can cascade into labor. In addition, studies have shown that vaccinated mothers are less likely to deliver prematurely than unvaccinated mothers.
The Take-Aways:
– Women who are nonwhite, less educated, less likely to be married, and more likely to smoke during pregnancy, conceive in the first half of the year.
– When controlled for maternal and birth characteristics, gestational length decreases about 0.8 week when conception occurs from January to May.
– There is a strong correlation between influenza infection and shortened gestation.
– Newborns conceived in the first 5 months of the year are of significantly lower birth weight than those conceived in the second half of the year.
– Average maternal weight gain increases by 0.8 pounds in the first half of the year, plateaus in June and August, then returns to the January level (may account for pattern in birth weights).
References:
1) http://well.blogs.nytimes.com/2013/07/15/really-babies-conceived-in-the-spring-are-more-likely-to-be-premature/?ref=health
2) http://www.ncbi.nlm.nih.gov/pubmed/23836632 (If you would like access to the full text, please let me know.)