Welcome to the home stretch! The third trimester begins during the 28th week of pregnancy and lasts until your baby’s birth. As your baby undergoes its greatest amount of growth, you may be growing weary of the pregnancy experience. This is totally natural – as are worries about whether your baby will be born healthy. Just continue to take care of your body, your baby, and your mind, and you’ll be a new mother in a few short weeks.
The third trimester.
What To Expect
Weight gain. You may experience more weight gain during the third trimester than any other period of your pregnancy. By the baby’s due date, you may weigh 25 to 35 pounds more than you did prior to the pregnancy. This weight gain is due to the baby itself, as well as the placenta, amniotic fluid, enlarged breasts and uterus, fat storage, and increased blood and fluid volume.
Contractions. If you didn’t begin experiencing Braxton Hicks contractions during the second trimester, you will almost certainly feel them now. Not to be alarmed, though – these contractions are just your body preparing for its big day. They’ll come and go with little warning, but they shouldn’t cause much pain. Actual labor contractions will be longer, stronger, and will get closer together in frequency.
Backaches. It’s fairly common to experience back pain as your baby continues to gain weight, and the hormones from pregnancy relax the joints in your pelvic area. Hip pain may occur as well. If the pain becomes intense, place a heating pad or ice pack on the affected area. Wear low-heeled shoes with good arch support. If the pain persists or is accompanied by other symptoms, talk to your doctor.
Shortness of breath. As your uterus expands beneath your diaphragm, you may find yourself getting winded after even the easiest of tasks. To reduce shortness of breath, practice good posture and sleep with your upper body propped up, to release pressure on your lungs. Aerobic exercise can also help, but be sure to talk to your doctor about how much exercise is healthy for you.
Swelling. As it grows, your uterus will put pressure on the veins responsible for returning blood from the lower extremities, which may lead to swelling in the feet and ankles. This swelling may lead to feelings of tingling or numbness in your legs, arms or hands. Meanwhile, fluid retention may leave you with a puffy face and eyelids. If these conditions persist for more than a couple of days, talk to your doctor.
Your Baby's Development
The third trimester is the homestretch of your pregnancy. Your belly is getting bigger by the week. Braxton Hicks contractions are growing more frequent. You may have trouble sleeping. Meanwhile, your baby continues to develop and grow at an amazingly rapid rate. His or her organs are maturing, as their little body prepares to be welcomed to the world.
Week 28: Now up to 10 inches in length, and weighing in at up to 2 ¼ pounds, your baby is beginning to look more and more like a little person. Its eyes are now partially open, and it even has fully-formed eyelashes.
Week 29: Now the baby is beginning to regulate his or her own body temperature, and the bone marrow is producing red blood cells. As the baby becomes more cramped in the uterus, its movements will feel smaller than those experienced during the second trimester.
Week 30: The bridge of your baby’s nose is now more apparent than ever. And the baby’s brain – which up to this point has been smooth in appearance – begins to form wrinkles and folds like an adult brain.
Week 31: The baby’s sexual organs continue to develop during week 31. If a boy, his testicles are moving down into the scrotum. In girls, the clitoris is now quite prominent.
Week 32: Your baby now has visible toenails, and he or she is now practicing breathing with his or her partially formed lungs. The baby’s body also is absorbing minerals such as iron and calcium.
Week 33: Weighing in at approximately 4 pounds, your baby’s brain is maturing quickly and increasing in size. You also have more amniotic fluid in your uterus – up to two pints.
Week 34: You may notice the milk beginning to activate in your breasts. Also, your baby’s fingernails have now grown long enough to reach his or her fingertips.
Week 35: By week 35, your baby’s body has achieved a nice, round shape, as it continues to gain fat. His or her suckle reflexes have developed by now, too.
Week 36: You may notice increased weight gain, as your baby continues to pack on the weight in preparation for birth. The good news is, as the baby gets comfy in your pelvis, you may find breathing gets easier.
Week 37: At this point, your baby is technically considered full-term. As your baby practices breathing in the amniotic fluid, her or she may even hiccup from time to time.
Week 38: Now your baby is nearing its birth weight – probably close to around 6.5 pounds. It’s also able to make a fist with its hands.
Week 39: In week 39, it’s fairly common to experience signs of labor. Start timing any contractions that you have. Meanwhile, the placenta is giving your baby antibodies that will help it fight infection after birth.
Week 40: Congratulations – you’ve reached the due date! Although healthy babies come in all different shapes and sizes, many weigh in at around 7.5 pounds and are about 14-15 inches in length.
Tests and Screenings
As your due date gets closer, it’s as important as ever to continue regular prenatal care. Expect weekly check-ups during the final month of your pregnancy.
Group B Strep. It’s common for most pregnant women to be screened for group B streptococcus (GB). This is a bacteria that, although usually harmless in adults, can infect babies and make them seriously ill. If you test positive for GBS, you’ll receive intravenous antibiotics in labor to protect your baby from it.
The baby’s position. It’s important to confirm that your baby is in a safe position prior to birth. Ideally, your doctor will be able to feel the baby’s head in your lower abdomen area. If this is the case for you, the pregnancy can proceed as planned. But if your baby is positioned feet- or rear-first (breech), then your doctor will make an effort to turn the baby around with a procedure known as external version. If this fails, a C-section may be necessary.
Cervical changes. The cervix softens, dilates and effaces (or thins) as birth approaches, and progress is measured in centimeters and percentages. You’ll be technically ready to deliver when your cervix is dilated 10 centimeters and is 100 percent effaced. Don’t get caught up worrying about numbers, however. Labor is different for every woman. Some even go into labor with no effacement or dilation whatsoever.