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Pregnancy and Childbirth

Baby’s Development during Pregnancy and What to expect – Trimester 3 (Weeks 28 – 40)

3rd trimester

Week 28: Baby’s eyes open

Twenty-eight weeks into your pregnancy, or 26 weeks after conception, your baby’s eyelids are partially open and eyelashes have formed. Your baby is gaining weight, which is smoothing out many of the wrinkles in his or her skin.

By now your baby may be nearly 10 inches (250 millimeters) long from crown to rump and weigh nearly 2 1/4 pounds (1,000 grams). Otherwise healthy babies born this week have a 90 percent chance of survival without physical or neurological impairment — and the odds improve with each passing week.

Week 29: Baby’s bones are fully developed

Fetal development 27 weeks after conception

Twenty-nine weeks into your pregnancy, or 27 weeks after conception, your baby’s bones are fully developed, but they’re still soft and pliable. This week, your baby begins storing iron, calcium and phosphorus.

Week 30: Baby’s eyes are wide open

Thirty weeks into your pregnancy, or 28 weeks after conception, your baby’s eyes are wide open. Your baby may have a good head of hair by this week.

By now your baby may be more than 10 1/2 inches (270 millimeters) long from crown to rump and weigh nearly 3 pounds (1,300 grams).

Week 31: Sexual development continues

Thirty-one weeks into your pregnancy, or 29 weeks after conception, your baby’s sexual development continues.

If your baby is a boy, his testicles are moving through the groin on their way into the scrotum. If your baby is a girl, her clitoris is now relatively prominent.

Week 32: Baby practices breathing

Thirty-two weeks into your pregnancy, or 30 weeks after conception, your baby’s toenails are visible.

Although your baby’s lungs aren’t fully formed, he or she practices breathing. Your baby’s body begins absorbing vital minerals, such as iron and calcium. The layer of soft, downy hair that has covered your baby’s skin for the past few months — known as lanugo — starts to fall off this week. Your baby’s kicks and jabs may be forceful.

By now your baby may be 11 inches (280 millimeters) long from crown to rump and weigh 3 3/4 pounds (1,700 grams).

Week 33: Baby detects light

Fetal development 31 weeks after conception

Thirty-three weeks into your pregnancy, or 31 weeks after conception, your baby’s pupils can constrict, dilate and detect light entering his or her eyes.

Week 34: Baby’s fingernails grow

Thirty-four weeks into your pregnancy, or 32 weeks after conception, your baby’s fingernails have reached his or her fingertips.

By now your baby may be nearly 1 foot (300 millimeters) long from crown to rump and weigh more than 4 1/2 pounds (2,100 grams).

Week 35: Protective coating thickens

Thirty-five weeks into your pregnancy, or 33 weeks after conception, your baby’s body has become round. The pasty white coating that protects your baby’s skin — the vernix caseosa — is getting thicker.

Week 36: Rapid weight gain begins

Thirty-six weeks into your pregnancy, or 34 weeks after conception, your baby is gaining weight rapidly — about 1/2 pound (227 grams) a week for the next month.

The crowded conditions inside your uterus may make it harder for your baby to give you a punch, but you’ll probably feel lots of stretches, rolls and wiggles. You may want to check on your baby’s movements from time to time — especially if you think you’ve noticed decreased activity. Ask your health care provider how many movements you should detect in a certain number of hours.

Week 37: Baby is full-term

Thirty-seven weeks into your pregnancy, or 35 weeks after conception, your baby will be considered full-term. Your baby’s organs are ready to function on their own. To prepare for birth, your baby may descend into the head-down position.

Week 38: Baby develops a firm grasp

Thirty-eight weeks into your pregnancy, or 36 weeks after conception, your baby is developing a firm grasp.

Your baby’s toenails have reached the tips of his or her toes. His or her brain and nervous system are working better every day. This developmental process will continue through childhood and adolescence.

By now your baby may be close to 13 1/2 inches (340 millimeters) long from crown to rump and weigh nearly 6 1/2 pounds (2,900 grams).

Week 39: Placenta provides antibodies

Thirty-nine weeks into your pregnancy, or 37 weeks after conception, your baby’s chest is becoming more prominent. For boys, the testes continue to descend into the scrotum. For girls, the labia majora is well developed.

Your baby has enough fat under the skin to maintain body temperature as long as there’s a little help from you. The placenta continues to supply your baby with antibodies that will help fight infection the first six months after birth. If you breast-feed your baby, your milk will provide additional antibodies.

Week 40: Your due date arrives

Fetal development 38 weeks after conception

Forty weeks into your pregnancy, or 38 weeks after conception, your baby may be more than 14 inches (360 millimeters) long from crown to rump and weigh about 7 1/2 pounds (3,400 grams). Remember, however, that healthy babies come in different sizes.

Don’t be alarmed if your due date comes and goes without incident. It’s just as normal to deliver a baby a week or two late — or early — than it is to deliver on your due date.

What to Expect

As your baby grows, his or her movements will become more obvious. These exciting sensations are often accompanied by increasing discomfort and other third trimester pregnancy symptoms.

  • As your baby continues to gain weight, pregnancy hormones relax the joints between the bones in your pelvic area. These changes can be tough on your back. Hip pain is common, too.

If you must stand, place one foot on a box or stool. Sit in chairs with good back support. Apply a heating pad or ice pack to the painful area. Ask your partner for a massage. Wear low-heeled — but not flat — shoes with good arch support. If the back pain doesn’t go away or is accompanied by other signs and symptoms, contact your health care provider.

  • Shortness of breath. You may get winded easily as your uterus expands beneath your diaphragm, the muscle just below your lungs. This may improve when the baby settles deeper into your pelvis before delivery. In the meantime, practice good posture and sleep with your upper body propped up on pillows to relieve pressure on your lungs. As long as your health care provider approves, aerobic exercise can help relieve this third trimester symptom, too.
  • During third trimester pregnancy, your growing uterus may push your stomach out of its normal position, which can contribute to heartburn. To keep stomach acid where it belongs, eat small meals and drink plenty of fluids. Avoid fried foods, carbonated drinks, citrus fruits or juices, and spicy foods. If this doesn’t help, ask your health care provider about antacids.
  • Spider veins, varicose veins and hemorrhoids. Increased blood circulation may cause small reddish spots that sprout tiny blood vessels on your face, neck or arms, especially if you have fair skin. Blue or reddish lines beneath the surface of the skin (varicose veins) also may appear, particularly in the legs. Varicose veins in your rectum (hemorrhoids) are another possibility.

If you have painful varicose veins, elevate your legs and wear support stockings. To prevent hemorrhoids, avoid constipation. Include plenty of fiber in your diet and drink lots of fluids.

  • Continued breast growth. By now, you may have an additional 2 pounds (nearly 1 kilogram) of breast tissue. As delivery approaches, your nipples may start leaking colostrum — the yellowish fluid that will nourish your baby during the first few days of life.
  • Frequent urination. As your baby moves deeper into your pelvis, you’ll feel more pressure on your bladder. You may find yourself urinating more often, even during the night. This extra pressure may also cause you to leak urine — especially when you laugh, cough or sneeze. You may want to wear nondeodorant panty liners for protection.

Continue to watch for signs of a urinary tract infection, such as urinating even more than usual, burning during urination, fever, abdominal pain or backache. Left untreated, a urinary tract infection may damage your kidneys and trigger preterm labor.

  • Braxton Hicks contractions. These contractions are warm-ups for the real thing. They’re usually weak and come and go unpredictably. True labor contractions get longer, stronger and closer together. If you’re having contractions that concern you, contact your health care provider.
  • Weight gain. By your due date, you may weigh 25 to 35 pounds (about 11 to 16 kilograms) more than you did before pregnancy. Your baby accounts for some of the weight gain, but so do the placenta, amniotic fluid, larger breasts and uterus, extra fat stores, and increased blood and fluid volume.
  • Vaginal discharge. Potentially heavy vaginal discharge is common at the end of pregnancy. If you saturate a panty liner within a few hours or wonder if the discharge is leaking amniotic fluid, contact your health care provider.
  • As your growing uterus puts pressure on the veins that return blood from your feet and legs, swollen feet and ankles may become an issue. At the same time, swelling in your legs, arms or hands may place pressure on nerves, causing tingling or numbness. Fluid retention and dilated blood vessels may leave your face and eyelids puffy, especially in the morning. If you have persistent face or eyelid swelling, contact your health care provider.

To reduce swelling, use cold compresses on the affected areas. Lying down or using a footrest may relieve ankle swelling. You might even elevate your feet and legs while you sleep. It may also help to swim or simply stand in a pool.

Ref: mayoclinic.com