Stages of pregnancy

• First trimester (week 1-week 12)

• Second trimester (week 13-week 28)

• Third trimester (week 29-week 40)

• Your developing baby

• More information on stages of pregnancy

Pregnancy lasts about 40 weeks, counting from the first day of your last normal period. The weeks are grouped into three trimesters (TREYE-mess-turs). Find out what's happening with you your baby in these three stages.

First trimester (week 1-week 12)

First trimester

See how your baby is growing inside of you during the first trimester.

Did you know?

For some women, body image is a huge concern during pregnancy. Learn what you can do to accept love your pregnant body in our Pregnancy body image section.

During the first trimester your body undergoes many changes. Hormonal changes affect almost every organ system in your body. These changes can trigger symptoms even in the very first weeks of pregnancy. Your period stopping is a clear sign that you are pregnant. Other changes may include:

• Extreme tiredness

• Tender, swollen breasts. Your nipples might also stick out.

• Upset stomach with or without throwing up (morning sickness)

• Cravings or distaste for certain foods

• Mood swings

• Constipation (trouble having bowel movements)

• Need to pass urine more often

• Headache

• Heartburn

• Weight gain or loss

As your body changes, you might need to make changes to your daily routine, such as going to bed earlier or eating frequent, small meals. Fortunately, most of these discomforts will go away as your pregnancy progresses. some women might not feel any discomfort at all! If you have been pregnant before, you might feel differently this time around. Just as each woman is different, so is each pregnancy.

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Second trimester (week 13-week 28)

Second trimester

See how your baby is growing inside of you during the second trimester.

Did you know?

You can do something about common pregnancy discomforts. Learn more.

Most women find the second trimester of pregnancy easier than the first. But it is just as important to stay informed about your pregnancy during these months.

You might notice that symptoms like nausea fatigue are going away. But other new, more noticeable changes to your body are now happening. Your abdomen will expas the baby continues to grow. before this trimester is over, you will feel your baby beginning to move!

As your body changes to make room for your growing baby, you may have:

• Body aches, such as back, abdomen, groin, or thigh pain

• Stretch marks on your abdomen, breasts, thighs, or buttocks

• Darkening of the skin around your nipples

• A line on the skin running from belly button to pubic hairline

• Patches of darker skin, usually over the cheeks, forehead, nose, or upper lip. Patches often match on both sides of the face. This is sometimes called the mask of pregnancy.

• Numb or tingling hands, called carpal tunnel syndrome

• Itching on the abdomen, palms, soles of the feet.(Call your doctor if you have nausea, loss of appetite, vomiting, jaundice or fatigue combined with itching. These can be signs of a serious liver problem.)

• Swelling of the ankles, fingers, face. (If you notice any sudden or extreme swelling or if you gain a lot of weight really quickly, call your doctor right away. This could be a sign of preeclampsia.)

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Third trimester (week 29-week 40)

Third trimester

See how your baby is growing inside of you during the third trimester.

You're in the home stretch! Some of the same discomforts you had in your second trimester will continue. Plus, many women find breathing difficult notice they have to go to the bathroom even more often. This is because the baby is getting bigger it is putting more pressure on your organs. Don't worry, your baby is fine these problems will lessen once you give birth.

Some new body changes you might notice in the third trimester include:

• Shortness of breath

• Heartburn

• Swelling of the ankles, fingers, face. (If you notice any sudden or extreme swelling or if you gain a lot of weight really quickly, call your doctor right away. This could be a sign of preeclampsia.)

• Hemorrhoids

• Tender breasts, which may leak a watery pre-milk called colostrum (kuh-LOSS-struhm)

• Your belly button may stick out

• Trouble sleeping

• The baby "dropping", or moving lower in your abdomen

• Contractions, which can be a sign of real or false labor

As you near your due date, your cervix becomes thinner softer (called effacing). This is a normal, natural process that helps the birth canal (vagina) to open during the birthing process. Your doctor will check your progress with a vaginal exam as you near your due date. Get excited — the final countdown has begun!

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Your developing baby

First trimester (week 1-week 12)

	At four weeks: Your baby's brain spinal cord have begun to form. The heart begins to form. Arm leg buds appear. Your baby is now an embryo one-twenty-fifth inch long.
	At eight weeks: All major organs external body structures have begun to form. Your baby's heart beats with a regular rhythm. The arms legs grow longer, fingers toes have begun to form. The sex organs begin to form. The eyes have moved forward on the face eyelids have formed. The umbilical cord is clearly visible. At the end of eight weeks, your baby is a fetus looks more like a human. Your baby is nearly 1 inch long weighs less than one-eighth ounce.
	At 12 weeks: The nerves muscles begin to work together. Your baby can make a fist. The external sex organs show if your baby is a boy or girl. A woman who has an ultrasound in the second trimester or later might be able to find out the baby's sex. Eyelids close to protect the developing eyes. They will not open again until the 28th week. Head growth has slowed, your baby is much longer. Now, at about 3 inches long, your baby weighs almost an ounce.

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Second trimester (week 13-week 28)

	At 16 weeks: Muscle tissue bone continue to form, creating a more complete skeleton. Skin begins to form. You can nearly see through it. Meconium (mih-KOH-nee-uhm) develops in your baby's intestinal tract. This will be your baby's first bowel movement. Your baby makes sucking motions with the mouth (sucking reflex). Your baby reaches a length of about 4 to 5 inches weighs almost 3 ounces.
	At 20 weeks: Your baby is more active. You might feel slight fluttering. Your baby is covered by fine, downy hair called lanugo (luh-NOO-goh) a waxy coating called vernix. This protects the forming skin underneath. Eyebrows, eyelashes, fingernails, toenails have formed. Your baby can even scratch itself. Your baby can hear swallow. Now halfway through your pregnancy, your baby is about 6 inches long weighs about 9 ounces.
	At 24 weeks: Bone marrow begins to make blood cells. Taste buds form on your baby's tongue. Footprints fingerprints have formed. Real hair begins to grow on your baby's head. The lungs are formed, but do not work. The hstartle reflex develop. Your baby sleeps wakes regularly. If your baby is a boy, his testicles begin to move from the abdomen into the scrotum. If your baby is a girl, her uterus ovaries are in place, a lifetime supply of eggs have formed in the ovaries. Your baby stores fat has gained quite a bit of weight. Now at about 12 inches long, your baby weighs about 1? pounds.

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Third trimester (week 29-week 40)

	At 32 weeks: Your baby's bones are fully formed, but still soft. Your baby's kicks jabs are forceful. The eyes can open close sense changes in light. Lungs are not fully formed, but practice "breathing" movements occur. Your baby's body begins to store vital minerals, such as iron calcium. Lanugo begins to fall off. Your baby is gaining weight quickly, about one-half pound a week. Now, your baby is about 15 to 17 inches long weighs about 4 to 4? pounds.
	At 36 weeks: The protective waxy coating called vernix gets thicker. Body fat increases. Your baby is getting bigger bigger has less space to move around. Movements are less forceful, but you will feel stretches wiggles. Your baby is about 16 to 19 inches long weighs about 6 to 6? pounds.
	Weeks 37-40: By the end of 37 weeks, your baby is considered full term. Your baby's organs are ready to function on their own. As you near your due date, your baby may turn into a head-down position for birth. Most babies "present" head down. At birth, your baby may weigh somewhere between 6 pounds 2 ounces 9 pounds 2 ounces be 19 to 21 inches long. Most full-term babies fall within these ranges. But healthy babies come in many different sizes.