Fetus
- Length: 35 to 38 cm.
- Weight: 1,200 g.
- Lung alveoli begin to mature, and surfactant can be demonstrated in amniotic fluid.
- Testes begin to descend into the scrotal sac from the lower abdominal cavity.
- The blood vessels of the retina are extremely susceptible to damage from high oxygen concentrations (an important consideration when caring for preterm infants who need oxygen).
- The eyes open.
Mother
- Your uterus is now well above your umbilicus. Sometimes this growth seems gradual. At other times, it may seem as though changes happen rapidly, as if overnight.
- Your uterus is about 3.2 inches (8cm) above your bellybutton. If you measure from the pubic symphysis, it is about 11 inches (28cm) to the top of the uterus. Your weight gain by this time should be between 17 and 24 pounds (7.7 and 10.8 kg).
[...] The first pregnancy poses little risk because it takes time for the mother’s antibodies to build up after being exposed to the antigens. But once they are formed, antibodies do not go away. The best course is to keep the mother from being sensitized and forming antibodies in the first place. If you are Rh negative and blood tests show that you have not become sensitized, your doctor will prescribe Rh immune globulin (RhIg) injections. This blood product prevents the mother from forming antibodies. It is usually injected right after the birth of your first baby to prevent harm to your next one. It may also be given during pregnancy, usually at about 28 weeks of pregnancy. [...]