Your Baby's Development
Your baby now weighs about 2 pounds, 2 ounces (1,000 grams) and measures about 10 inches (25 cm) from crown to rump. At your next prenatal appointment, your health care provider may tell you whether your baby is headfirst or feet- or bottom-first (called breech position) in the womb. Babies who are in the breech position may need to be delivered by cesarean section. Your baby still has 2 months to change position, though, so don't worry if your baby is in the breech position right now. Most babies will switch positions on their own.
Your health care provider probably sent you for some blood tests early in your pregnancy. One thing blood tests measure is the Rh factor, a substance found in the red blood cells of most people. If you don't have it (if you’re Rh negative) but your baby does (is Rh positive), there is potential for your baby to have health problems, such as jaundice and anemia. Your doctor can prevent these problems by giving you a vaccine called Rh immune globulin at 28 weeks and again after delivery.