Babies who were conceived in May had a 10% higher risk of being born prematurely than those conceived at other times of the year, according to a study in the Proceedings of the National Academy of Sciences. The researchers said the association may be a function of a pregnant woman's increased exposure to the seasonal flu during January and February. Researchers also noted that babies conceived during the summer were slightly heavier at birth, weighing an average of 8 grams to 9 grams more than babies conceived in other seasons.

Related Summaries