Explain fetal development during the three trimesters of gestation

Pregnancy begins with the fertilization of an egg and continues through to the birth of the individual. The length of time of gestation varies among animals, but is very similar among the great apes: human gestation is 266 days, while chimpanzee gestation is 237 days, a gorilla’s is 257 days, and orangutan gestation is 260 days long. The fox has a 57-day gestation. Dogs and cats have similar gestations averaging 60 days. The longest gestation for a land mammal is an African elephant at 640 days. The longest gestations among marine mammals are the beluga and sperm whales at 460 days.

What You’ll Learn to Do

• Explain fetal development during the three trimesters of gestation
• Describe labor and delivery
• Compare the efficacy and duration of various types of contraception
• Discuss causes of infertility and the therapeutic options available

Learning Activities

The learning activities for this section include the following:

• Human Gestation
• Labor and Birth
• Contraception and Birth Control
• Infertility
• Self Check: Human Pregnancy and Birth