Your Body in the Third Trimester of Pregnancy



 picture 36 weeks pregnant
36 weeks pregnant larger picture view larger picture
36 weeks pregnant picture

Source: The Growing Uterus Charts,
© 1985, 2006 Childbirth Connection

The third trimester is a busy time. You and your partner will be asking yourselves a lot of questions, and making many decisions that will affect you as individuals, as partners, and as new parents over the months to come.

In this trimester, your body prepares for labor and birth.
  • By the end of the seventh month, the uterus will fill almost the entire abdominal cavity, and the fundus is about one third of the distance between your belly button and your breastbone. By the end of this trimester, it will be almost level with the breastbone, just under your rib cage.

  • The ligaments (bands of flexible tissue) supporting the uterus continue to stretch; the muscles and ligaments in the lower back are pulled by the weight of the growing uterus and may cause your back to ache. Occasionally, you'll feel the uterus tighten and release, in what are known as Braxton Hicks contractions, as your body “rehearses” for labor.

  • The uterus also places increasing pressure on the bladder and you will feel the urge to urinate often. You may leak urine when you cough or sneeze; talk to your health care provider or childbirth educator to learn special exercises (called Kegel exercises) to help strengthen the muscles in your pelvic floor.

  • The diaphragm continues to move upward and the ribs expand to make room for the baby. Toward the end of your pregnancy, some of the pressure will ease as your baby drops into position for birth, making breathing a little easier again.

  • Your belly now has a dark line running from your navel to your pubic hair. This will fade after the baby is born. You may have stretch marks and/or an “itchy abdomen”.

  • Your breasts will continue to change to prepare them for breastfeeding. (Note that even if you don't plan to breastfeed, your breasts still go through these changes.) By the end of the seventh month and the beginning of the eighth, you may notice small amounts of thick, yellowish liquid called colostrum on your nipples.

  • You may get leg cramps, some strong enough to wake you from sleep. They disappear by themselves. Experts are not certain what causes them but suspect it may have to do with a mineral deficiency. So make sure to take your daily prenatal supplement to prevent mineral deficiency. Elevate your legs two to three times a day to help circulation.

  • At the beginning of this trimester, the cervix is long and thick. The vagina and the urethra (the neck of the bladder) are stretching in preparation for birth. During the last weeks of your pregnancy, the perineum (the tissue between the vagina and the anus) will become swollen from the extra pressure on it.

Continue to "Your Baby: What's Happening" journey to parenthood


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Childbirth Connection is a national not-for-profit organization founded in 1918 as Maternity Center Association. Our mission is to improve the quality of maternity care through research, education, advocacy and policy. Childbirth Connection promotes safe, effective and satisfying evidence-based maternity care and is a voice for the needs and interests of childbearing families.
Most recent page update: 9/9/2010