A timing issue

Babies Take Longer To Come Out Than They Did In Grandma's Day : Shots - Health News : NPR

The typical first-time mother takes 6 1/2 hours to give birth these
days. Her counterpart 50 years ago labored for barely four hours.

That's the striking conclusion of a new federal study that compared nearly 140,000 births from two time periods.

Well I didn't know that. Possible reasons are included in the article.