Twins—smaller at birth, on average, than singletons—start out smaller in pregnancy than was previously known, according to a study by researchers at the National Institutes of Health (NIH). The ...

A twin pregnancy is when there are two fetuses in the uterus at the same time. Twins can be identical, meaning they developed when a single fertilized egg split early in development, or fraternal, ...

Identical (monozygotic) twins develop from a single egg-sperm combination that splits into two. If the split is delayed, usually a week or so after conception, the processes of growing a placenta, ...

Amanda Cerny welcomes twin babies with partner Johannes Bartl, saying “we are over the moon.” Doctors explain complications linked to twin pregnancies.

It was less than an hour before my cesarean section, even though my due date was still six weeks away. My doctor had determined that one of my twin babies was at risk of being stillborn if I didn’t ...

The number of twins and triplets born can vary significantly between IVF clinics, new data shows, but experts warn that ...