Endometrial cancer is one of the most common types of gynecological cancers in the world. The exact reason for the onset of new cancer is unknown, but recent evidence suggests a link between pregnancy duration and endometrial cancer. This study aims to evaluate the association between the duration of pregnancy and the risk of endometrial cancer.

This is a nationwide register-based cohort study conducted on a total of 2,331,332 Danish women with 3,947,650 pregnancies. The study’s primary outcome was a relative risk of endometrial cancer by the number, type, and duration of pregnancy.

The researchers found that a total of 6,743 women developed endometrial cancer during 57,347,622 person-years of follow-up. It was found that the first pregnancy was associated with a reduced risk of endometrial cancer, regardless of the pregnancy outcome. However, each subsequent pregnancy was associated with an increased risk of endometrial cancer. Other factors like type, age, and duration of pregnancy did not affect the risk of endometrial cancer.

The research concluded that the risk of endometrial cancer is reduced in the first pregnancy. However, there is an increased risk of endometrial cancer with every subsequent pregnancy. The research also concluded that the risk is not associated with other factors like age, type, and pregnancy duration.

Ref: https://www.bmj.com/content/366/bmj.l4693