Your baby has definite sleep-and-wake cycles, but she probably sleeps about 70 percent of the time. Ultrasounds reveal that sometime between 32 weeks and 36 weeks babies develop the ability to dream. They have definite periods of REM (rapid eye movement) sleep and non-REM sleep. Your baby also has periods of quiet alertness in which she listens to the exciting sounds beyond her dark room.
At almost 4 pounds, your baby is definitely big enough by now to survive outside the womb. Her lungs are maturing, and her heart rate is starting to slow down a bit. However, research shows that the fetal heart rate speeds up if the mother is stressed, so stay as relaxed as you can to help your baby stay peaceful.
Your baby is still kicking, and all of that kicking is good practice for what she'll instinctively do if she's put on your belly after birth: She'll scramble her way up your belly to your breasts, where she will latch on and nurse.
During your last trimester, your health care provider might request an ultrasound for several reasons. Some providers routinely ask for a third trimester ultrasound, while others might only order an examination if there is a specific concern.
This list includes some of the common reasons to perform an ultrasound at this point in your pregnancy:
- Evaluation of fetal growth. The sonographer will measure certain parts of your unborn baby's body to confirm that he's growing properly.
- Vaginal bleeding; abdominal or pelvic pain. An ultrasound might indicate reasons for bloody discharge or aches.
- Cervical insufficiency. A sonographer will perform a careful evaluation of the cervix to make sure it has not begun to efface (shorten) or dilate as a result of the heavier baby pushing down on the cervix.
- Determination of fetal presentation. Through the ultrasound, the sonographer can confirm whether the unborn baby is in the proper position for birth -- head down toward the pelvis.
- Evaluation of fetal well-being. During an ultrasound examination, the sonographer will look to see that the baby is moving.
- Premature rupture of membranes or premature labor. If you are experiencing preterm labor pains, an ultrasound examination can confirm that the cervix is effacing or look for other signs your body is readying for birth.
- Placenta previa. If previous ultrasounds have indicated that you have placenta previa, or if your provider suspects this condition, an ultrasound examination will confirm that the placenta is still in position over the cervical opening.
Terms to Know
Incompetent cervix: According to the American Pregnancy Association, an incomplete or weakened cervix may occur as the baby grows and gets heavier, pressing against the cervix. This pressure may cause the cervix to begin opening before Baby is ready to be born. This condition may lead to a miscarriage or premature delivery (however, this complication occurs in only about 1 out of 100 pregnancies).
Important Information About Your Pregnancy
- Learn more about your baby in the third trimester.
- Discover more about your 32nd week of pregnancy.
- Read about your previous week of pregnancy.
- Learn what to expect during your next week of pregnancy.
Copyright © 2010 Meredith Corporation.
Images courtesy of the American Institute of Ultrasound in Medicine (AIUM.org).