Women's  Healthcare Topics is a website about pregnancy and your newborn baby.

Body Changes in Third Trimester of Pregnancy

Reviewed by James Brann, M.D.

The Third Trimester Continues to Produce Body Changes

Common third trimester ailments and body changes.

Because the external changes are so obvious, people tend to forget that the changes inside are occurring. It's not just weight that is affecting you, there's so much going on inside you as you grow that baby to her blooming point and prepare for the ultimate workout - delivery and recovery.

Common Third Trimester Ailments

Heartburn, constipation, gas, leg cramps, cravings, and a whole host of other ailments which occurred in the previous trimesters often continue to rear their ugly heads. If only you could catch a break. Your break is coming, I promise.
Soon you'll be singing lullabies to an external audience and maybe you'll forget about a lot of these less than pleasant pregnancy problems. I know that sounds unlikely, but I've seen it time after time in my office. If you're lucky, you'll be one of those women who can be heard saying, "Oh, I loved every part of my pregnancy...even the unpleasant parts because they reminded me that my baby was growing and thriving."

Are you tired of the wait? Or tired of the weight? Most women will be heard announcing that they are eager to be done with pregnancy at least once during their last trimester. You know in your head that pregnancy is forty weeks long, but do you sometimes think you'll be pregnant forever? You really are approaching that most exciting of finish lines, only to begin the journey of parenthood. What bumps in the road might you experience on your way to that finish?

The Physiological Changes

  • The greatest weight gain occurs in the third trimester.

  • Your uterus grows from its early third trimester position at the belly button all the way to the breastbone. It also expands outward which may create pressure in the abdomen, back, sides and pelvic pain.

  • Blood volume/flow continues to increase.

  • The hormone relaxin softens the ligaments at the joints of your pelvic bones and can cause you to become clumsier.

  • Breast size increases yet again and milk production glands continue to prepare for nursing.

  • Body temperature may rise slightly . Periods of feeling overheated and having hot flashes.

  • Water retention may cause your hands, feet, and ankles to swell. If swelling is extreme or swelling of the face occurs, inform your doctor.

  • Changes in blood flow may cause headaches. Changes in blood flow combined with increased abdominal or rectal pressure may cause the walls of veins to thin out or stretch causing varicose veins or hemorrhoids.

  • Vaginal secretions increase.

  • Hormones trigger Braxton Hicks contractions, mild contractions of the uterus which occur for short intervals and cause mild discomfort; many consider Braxton Hicks contractions to be the uterus' way of getting ready for delivery.

  • Frequent urination returns as your growing baby exerts pressure on your bladder.

  • Fatigue All the extra weight and work the body must do during the third trimester results in fatigue for many women.

All this change is a result of your body's amazing capacity to eventually house a seven pound, 20 inch long little person (more or less). Pretty impressive what your body can do, isn't it?

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