Week-by-Week Pregnancy

Here's your one-stop guide to every week of pregnancy. Click on any week for a more detailed description of your pregnancy.

Week 21: If you're 35 or older, have chronic high blood pressure or diabetes or are carrying multiples, you are at a higher risk of preeclampsia. It can occur this early, but usually doesn't set in until the third trimester. Read more about being 21 weeks pregnant.

Week 22: The brain has entered a phase of extremely rapid growth. Length: about 11 inches; weight: just under 1 pound. Read more about being 22 weeks pregnant.

Week 23: The testicles begin to descend into the groin from the abdomen; the uterus and ovaries have developed. Body proportions are similar to a newborn’s, though the fetus is still thin. The eyes are formed but lack pigmentation. Length: about 11 1∕2 inches; weight: about 1 pound. Read more about being 23 weeks pregnant.

Week 24: The fetus develops waking/sleeping patterns. Real hair (not lanugo) begins to grow on the head. Length: about 12 inches; weight: 1 ¼ pounds. Fetus fact: If born now, your baby would have about a 50 percent chance of surviving. Read more about being 24 weeks pregnant.

Week 25: You may be afflicted with heartburn and leg cramps, especially at night.
Read more about being 25 weeks pregnant.

Week 26: The eyelids separate and the eyes are starting to open. Lungs are beginning to develop surfactant, which allows them to inflate. The fetus begins to sleep for longer periods, often when you do. Length: 14 inches; weight: almost 2 pounds.Read more about being 26 weeks pregnant.

Week 27: You may be distressed to see the numbers on the scale creep (OK, jump) up: From here on out, you'll probably be gaining about 1 pound a week. This still only translates to about 300 extra calories a day, though. Read more about being 27 weeks pregnant.

Week 28: The fetus can taste and smell, and the eyes can produce tears. The bones are almost fully developed though stillsoft. Weight gain is rapid from now on. Length: about 15 inches; weight: more than 2 1∕2 pounds.Fetus fact: The brain will increase 400 percent to 500 percent in weight between now and delivery.
Read more about being 28 weeks pregnant.

Week 29: The basketball-sized lump in your belly may be inhibiting shoe tying, leg shaving and the like. The fetus is increasingly sensitive to light and sound. Read more about being 29 weeks pregnant.

Week 30: You might find yourself increasingly breathless as your growing uterus crowds your diaphragm. It should ease a bit when the baby drops lower in your pelvis later in pregnancy. Read more about being 30 weeks pregnant.

Week 31: All major organs except the lungs are completely developed. The eyes
are wide open.Read more about being 31 weeks pregnant.

Week 32: The fetus practices breathing motions inpreparation for birth. All five senses are developed, and REM (dream-cycle) sleep is beginning. Lanugo begins to disappear. Length: about 17 inches; weight: about 4 pounds. Fetus fact: If your babywere born now, he would have an excellent chance of surviving without life-threatening complications. Read more about being 32 weeks pregnant.

Week 33: Don't get too married to your dream delivery: Even if you're hoping for a vaginal birth, there's a nearly 1 in 3 chance you'll have a C-section. Read more about being 33 weeks pregnant.

Week 34: The fetus is taking deep breaths. The eyes can blink and are open when it’s awake and closed when asleep, and the pupils dilate and constrict in reaction to light. Length: about 18 inches; weight: about 5 pound. Read more about being 34 weeks pregnant.

Week 35: There's a good chance your body harbors Group B streptococcus bacteria without your knowing it. If it colonizes in the vagina and is left untreated, it can infect your baby at birth. Read more about being 35 weeks pregnant.

Week 36: The baby may drop lower into your pelvis in preparation for delivery. This should make it easier to breathe—yet your pee breaks will become ever more frequent. Read more about being 36 weeks pregnant.

Week 37: Activity levels are consistent and predictable, and the organs are ready to function on their own. The fetus may move to the headfirst position in preparation for labor. Length: about 19 inches; weight: about 6 pounds. Fetus fact: The baby will gain about 1∕2 pound per week until delivery. Read more about being 37 weeks pregnant.

Week 38: Your pregnancy is considered full-term now, and the lanugo—the downy hair that covered your baby's body—is starting to disappear. Read more about being 38 weeks pregnant.

Week 39: Lanugo has almost completely disappeared. The fetus drinks approximately 15 ounces of amniotic fluid per day, and hiccups are common. Testicles begin todescend from the groin into the scrotum; the labia are well-developed. Read more about being 39 weeks pregnant.