Fall Is The Best Time To Conceive, According To New BU Study

BOSTON (CBS) -- What is the best season to try to get pregnant? A new study from the Boston University School of Public Health shows it's not when most people start trying to conceive.

While birthdays across the United States peak in early September, in northern states, most babies are born in the summer or even spring.

Researchers at BU looked at data on more than 14,000 women who were trying to get pregnant from the US, Canada and Denmark.

They found that while couples are most likely to begin attempting to conceive in September, it's not until late November or early December that they have the best chances of success, especially for couples living in the south.

It's not clear why seasonal variability in fertility may exist. Researchers say temperature, humidity, vitamin D and air pollution could possibly contribute.