Pregnancy occurs when a sperm fertilizes an egg after it is released from the ovary during ovulation. The fertilized egg then travels down into the uterus, where implantation occurs. A successful implantation results in pregnancy. On average, a full-term pregnancy lasts 40 weeks. There are many factors that can affect a pregnancy. Women who receive an early diagnosis and prenatal care are more likely to experience a healthy pregnancy and give birth to a healthy baby. Knowing what to expect during the full pregnancy term is also important for monitoring your health and the health of the baby. If you would like to prevent pregnancy, there are also effective forms of birth control to keep in mind.