Healthy pregnancy (16)
- Childbirth education: Get ready for labor and delivery
- Working during pregnancy: Do's and don'ts
- Pregnancy nutrition: Foods to avoid during pregnancy
- see all in Healthy pregnancy
First trimester (6)
- Fetal development: The first trimester
- First trimester pregnancy: What to expect
- Prenatal care: What to expect during the first trimester
- see all in First trimester
Second trimester (7)
- Fetal development: The second trimester
- Second trimester pregnancy: What to expect
- Prenatal care: What to expect during the second trimester
- see all in Second trimester
Third trimester (9)
- Fetal development: The third trimester
- Overdue pregnancy: What to do when baby's overdue
- Third trimester pregnancy: What to expect
- see all in Third trimester
Pregnancy problems (14)
- Heart problems and pregnancy: Know the risks
- High blood pressure and pregnancy: Healthy mom, healthy baby
- Epilepsy and pregnancy: What you need to know
- see all in Pregnancy problems
Mayo Clinic Health Manager
Get free personalized health guidance for you and your family.
Get Started
About our e-newsletters
- Free e-newsletters
- Mayo Clinic expertise
- We do not share your e-mail address
Housecall, our weekly general-interest e-newsletter, keeps you up to date on a wide variety of health topics with timely, reliable, practical information, recipes, blogs, questions and answers with Mayo Clinic experts and more. Our biweekly topic-specific e-newsletters also include blogs, questions and answers with Mayo Clinic experts, and other useful information that will help you manage your health.
Housecall Archives
Mayo Clinic Housecall
Stay up to date on the latest health information.
What you get
- Free weekly e-newsletter
- Mayo Clinic expertise
- Recipes, tools and other helpful information
- We do not share your e-mail address
Fetal development: The third trimester
Fetal development continues during the third trimester. Your baby will open his or her eyes, gain more weight and prepare for delivery.
By Mayo Clinic staffThe end of your pregnancy is near! By now, you may be tired of being pregnant — and eager to meet your baby face to face. But your uterus is still a busy place. Understand how fetal development continues as you approach your due date. Here's a weekly calendar of events for the third 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
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
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.
Next page(1 of 2)
- Healthy pregnancy: Stages of pregnancy. U.S. Department of Health and Human Services. http://www.4women.gov/pregnancy/you-are-pregnant/stages-of-pregnancy.cfm#second. Accessed March 20, 2009.
- How your baby grows during pregnancy. The American College of Obstetricians and Gynecologists. http://www.acog.org/publications/patient_education/bp156.cfm. Accessed March 20, 2009.
- Knuppel A. Maternal-placental-fetal unit; Fetal & early neonatal physiology. In: DeCherney AH, et al. Current Diagnosis & Treatment Obstetrics & Gynecology. 10th ed. New York, N.Y.: The McGraw-Hill Companies; 2007:1.
- Cunningham FG, et al. Williams Obstetrics. 22nd ed. New York, N.Y.: The McGraw-Hill Companies; 2005:1.
- My 9 months: Month nine. March of Dimes. http://www.marchofdimes.com/hbhb_syndication/18622_2145.asp. Accessed April 27, 2009.
- Moore KL, et al. The Developing Human: Clinically Oriented Embryology. 8th ed. Philadelphia, Pa.: Saunders Elsevier; 2003:4.
- What to expect after your due date. The American College of Obstetricians and Gynecologists. http://www.acog.org/publications/patient_education/bp069.cfm. Accessed May 13, 2009.
- Harms RW (expert opinion). Mayo Clinic, Rochester, Minn. May 28, 2009.
