1. Name the three layers present in 3-week-old embryos and describe what each la

1. Name the three layers present in 3-week-old embryos and describe what each layer will
later form.
2. Your friend Chloe is pregnant and she told you that she knows the three stages of prenatal
development but she wasn’t sure what happens during each stage. What are these stages
called, what weeks of development does each stage last for, and what happens during
each stage?
3. Chloe is concerned about the amount of weight that she will gain during pregnancy. She
doesn’t want to get “too fat.” She has heard of women who gain only 10 pounds while
pregnant and they wear their pre-maternity clothes home from the hospital. What can
you tell Chloe about weight gain during pregnancy?
4. What are four general principles governing the influence of teratogens on prenatal
development?
5. Describe ultrasound, amniocentesis, and chorionic villus sampling and the kind of
information that can be obtained from each.
6. Describe the three stages of labor and delivery.
7. Chloe wonders how long her labour will last. She has heard stories about women whose
labours are so short that they had their babies in the back of a car or an elevator. What
can you tell Chloe about the typical length of labour for a first-born child?