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Pregnancy Week by Week

cross section of the female belly in the 40th week of pregnancy

Looking for a week-by-week guide to pregnancy? You're in luck! We've got loads of expert-approved info about each week and trimester, including what's up with your growing baby and what changes to expect for yourself.

You'll find stunning fetal development videos, thousands of articles, and helpful tools like our Due Date Calculator and Baby Names Finder. Meet other parents-to-be in our online community, and get all of this and more in our free pregnancy app. Dive in, and congratulations!

First Trimester of Pregnancy

Second Trimester of Pregnancy

Third Trimester of Pregnancy

First Trimester of Pregnancy

fertilization of egg

2 weeks pregnant

Ovulation may happen about two weeks after your last period began. If egg meets sperm, you're on your way to being pregnant.

blastocyst which will develop into embryo and placenta

3 weeks pregnant

At 3 weeks after your last period - about 1 week after fertilization - your baby is a tiny ball made up of several hundred cells that are multiplying quickly.

embryo made up of hypoblast and epiblast

4 weeks pregnant

At 4 weeks, your baby is an embryo made up of two layers, and your primitive placenta is developing.

three levels of embryo, ectoderm, mesoderm, and endoderm

5 weeks pregnant

At 5 weeks, your tiny embryo is growing like crazy, and you may be noticing pregnancy discomforts like sore breasts and fatigue.

close up of developing baby

6 weeks pregnant

At 6 weeks, your baby's heart has started beating. You may have morning sickness and sore breasts.

baby with developing eyes

7 weeks pregnant

At 7 weeks, your baby's eyes, nose, mouth, and ears are taking shape. You may need to pee constantly.

baby with webbed fingers and toes

8 weeks pregnant

At 8 weeks, your baby's hands and feet are sprouting webbed fingers and toes. You may have nausea and fatigue. And you may make decisions about prenatal tests.

baby with tiny tooth buds

9 weeks pregnant

At 9 weeks, your baby is starting to look more like a tiny human. You may have morning sickness and mood swings.

baby with eyelids now covering eyes

10 weeks pregnant

At 10 weeks, your baby has finished the most critical part of development! You might be ready for maternity clothes, or at least some new bras.

baby at start of fetal period

11 weeks pregnant

At 11 weeks pregnant, your baby's busy kicking and stretching. But you won't feel that for a while yet.

baby with fingers opening and closing

12 weeks pregnant

Your baby can curl those tiny toes and make sucking movements when you're 12 weeks pregnant. You may be having heartburn.

baby in amniotic fluid

13 weeks pregnant

At 13 weeks pregnant, you're in the last week of the first trimester. Your baby now has exquisite fingerprints and is almost 3 inches long.

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Second Trimester of Pregnancy

belly starting to show at 14 weeks

14 weeks pregnant

Your baby is now making expressions with its tiny features. At 14 weeks pregnant, you may be feeling more energetic and less nauseated.

baby in womb at 15 weeks

15 weeks pregnant

At 15 weeks, your baby can move her joints and is forming taste buds. Have a stuffy nose? It's a surprising pregnancy side effect.

baby in womb with ligaments of uterus thickening at 16 weeks

16 weeks pregnant

At 16 weeks pregnant, you may be having less nausea and fewer mood swings. Your baby is heading into a growth spurt.

baby in body at 17 weeks

17 weeks pregnant

At 17 weeks, your baby's skeleton is changing from soft cartilage to bone, and the umbilical cord is growing stronger and thicker.

baby in womb at 18 weeks

18 weeks pregnant

Your baby's genitals are developed enough to see on an ultrasound. Hungry? An increase in appetite is normal at 18 weeks pregnant.

baby in body at 19 weeks

19 weeks pregnant

At 19 weeks, hair is sprouting on your baby's scalp. If your sides are aching, it could be round ligament pain.

baby in womb at 20 weeks, top of uterus level with navel

20 weeks pregnant

At 20 weeks pregnant, you're at the halfway mark in your pregnancy - congrats! Your baby's taste buds are now working.

baby in body with uterus pushing against intestines

21 weeks pregnant

Feeling your baby move at 21 weeks pregnant? Those early flutters will turn into full-fledged kicks. Cool fact: Your baby has eyebrows now.

baby in womb at 22 weeks

22 weeks pregnant

At 22 weeks, your baby may be able to hear your heartbeat. And your growing belly may be turning into a hand magnet.

baby in body at 23 weeks

23 weeks pregnant

Now that you're 23 weeks pregnant, your baby has a well-developed sense of movement. Meanwhile, you may notice swelling in your ankles and feet.

baby in belly at 24 weeks

24 weeks pregnant

At 24 weeks, your baby is still long and lean -- but that will soon change. And your growing uterus is now the size of a soccer ball.

baby in body at 25 weeks

25 weeks pregnant

At 25 weeks, your little one is starting to add some baby fat and grow more hair. Your hair may be looking extra lustrous, too.

baby in womb at 26 weeks

26 weeks pregnant

At 26 weeks, your baby is inhaling and exhaling small amounts of amniotic fluid. This is good practice for breathing.

baby in womb pushing against stomach at 27 weeks

27 weeks pregnant

At 27 weeks pregnant, you may feel your baby hiccupping. He's also opening and closing his eyes and even sucking his fingers.

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Third Trimester of Pregnancy

baby in head down position at 28 weeks

28 weeks pregnant

At 28 weeks pregnant, you're starting your last trimester. Your baby's eyes may be able to see light filtering in through your womb.

baby in womb at 29 weeks with uterus pushing against diaphragm

29 weeks pregnant

At 29 weeks, your baby's muscles and lungs are maturing, and her head is growing to make room for her developing brain.

baby in womb at 30 weeks

30 weeks pregnant

At 30 weeks, your baby weighs almost 3 pounds. You may be battling mood swings, clumsiness, and fatigue.

baby in body at 31 weeks

31 weeks pregnant

At 31 weeks, your baby's strong kicks might be keeping you up at night. You may be feeling Braxton Hicks contractions, too.

baby in womb at 32 weeks

32 weeks pregnant

Your baby is plumping up! At 32 weeks pregnant, your expanding uterus may cause heartburn and shortness of breath.

baby in womb at 33 weeks pressing on bladder

33 weeks pregnant

At 33 weeks pregnant, you might be waddling and having trouble getting comfy in bed. Your baby weighs a little more than 4 pounds now.

baby in womb at 34 weeks

34 weeks pregnant

At 34 weeks, your baby's central nervous system and lungs are maturing. Dizziness and fatigue may be slowing you down.

baby in womb at 35 weeks, uterus expanded to rib cage

35 weeks pregnant

At 35 weeks, your baby is too snug in your womb to do a lot of somersaults, but you'll still feel frequent movements.

baby in body at 36 weeks moving toward birth canal

36 weeks pregnant

Your baby is gaining about an ounce a day now that you're 36 weeks pregnant. You may feel her "drop" down into your pelvis soon.

baby in womb at 37 weeks, quite cramped in womb

37 weeks pregnant

At 37 weeks, your baby's brain and lungs are continuing to mature. You may have more vaginal discharge and occasional contractions.

baby in womb at 38 weeks compressing bladder

38 weeks pregnant

Your baby has a firm grasp, which you'll soon be able to test in person! At 38 weeks pregnant, it's wise to watch for signs of preeclampsia.

full term baby in womb at 39 weeks with cervix thinning and dilating

39 weeks pregnant

At 39 weeks pregnant, your baby is full term and waiting to greet the world! If your water breaks, call your healthcare provider.

baby in womb at 40 weeks

40 weeks pregnant

At 40 weeks pregnant, your baby is the size of a small pumpkin! Don't worry if you're still pregnant - it's common to go past your due date.

baby in womb at 41 weeks awaiting possible induction

41 weeks pregnant

At 41 weeks pregnant, you'll go into labor or be induced soon. Your baby should remain active right up until delivery.

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Latest in pregnancy week by week

baby in womb at 41 weeks awaiting possible induction

41 weeks pregnant

Reviewed by Layan Alrahmani, M.D., ob-gyn, MFM

baby in womb at 40 weeks

40 weeks pregnant

Reviewed by Layan Alrahmani, M.D., ob-gyn, MFM

embryo made up of hypoblast and epiblast

4 weeks pregnant

Reviewed by Layan Alrahmani, M.D., ob-gyn, MFM

blastocyst which will develop into embryo and placenta

3 weeks pregnant

Reviewed by Layan Alrahmani, M.D., ob-gyn, MFM

full term baby in womb at 39 weeks with cervix thinning and dilating

39 weeks pregnant

Reviewed by Layan Alrahmani, M.D., ob-gyn, MFM

baby in womb at 38 weeks compressing bladder

38 weeks pregnant

Reviewed by Layan Alrahmani, M.D., ob-gyn, MFM

fertilization of egg

2 weeks pregnant

Reviewed by Layan Alrahmani, M.D., ob-gyn, MFM

baby in body at 36 weeks moving toward birth canal

36 weeks pregnant

Reviewed by Layan Alrahmani, M.D., ob-gyn, MFM

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