A pregnancy is the time in which a fertilized egg cell grows into a child inside the body of a person with a uterus.
The pregnancy lasts, from fertilization to birth, 267 days on average. The last menstruation began about 14 days before fertilization and is the starting point for the official count of pregnacy time which then means that pregnancy lasts 40 weeks (roughly 10 month).
Pregnancy:
(Picture: Messe Duesseldorf/Constanze Tillmann)