You and Your Baby: Month-by-Month

First Trimester
Second Trimester
Third Trimester

MONTH 1 (1–4 weeks)

What happens to your baby?

  • Tiny limb buds appear, which will grow into arms and legs.
  • The heart and lungs form, and by the 22nd day, the heart starts to beat.
  • The neural tube forms, which becomes the brain and spinal cord.
  • Your baby will be about 1/4 inch long at the end of the first month.

What happens to your body?

  • You are making lots of hormones needed for your baby's growth. These hormones change many of your organs.
  • Your breasts become slightly big and sore. You also may feel tingling.
  • You may develop morning sickness. Try eating more carbohydrates, especially salty carbohydrates like crackers
  • Your taste in food may change, craving for and disliking certain food.

Guide to prenatal care:

  • Visit your healthcare provider for your first prenatal care checkup as soon as you think you are pregnant.
  • If this is a planned pregnancy, you already should be taking multivitamins that contain 400 micrograms to 1 gram of folic acid every day and continue to take it during pregnancy.
  • Please ask your healthcare provider before taking any prescription drugs, over-the-counter products, or herbal products.
  • STOP smoking, STOP drinking alcohol, and STOP taking recreational drugs.
  • Prevent overheating, and avoid hot tubs.

Lab tests:

  • Initial blood tests
  • CBC
  • Blood type and Rh
  • Antibodies screen
  • RPR
  • Rubella
  • Hepatitis B
  • HIV test (with your consent)
  • Other test depending on your history, such as sickle cell trait and diabetes testing. 

MONTH 2 (5–8 weeks)

What happens to your baby?

  • Your baby's major organs are formed but not completely developed.
  • The placenta, which exchanges nutrients from your body for waste products produced by the baby, is visible and working.
  • The eyelids are formed and grow but are sealed shut. The ears, wrists, and ankles also are formed.
  • Fingers and toes are developed. 
  • Your baby will be about 1 inch long and will weigh less than 1/3 ounce by the end of the second month.

What happens to your body?

  • Your breasts will be sore and will continue to enlarge; the nipples and area around them will begin to darken.
  • Your uterus is growing and pressing on your bladder, so you will urinate more often.
  • Morning sickness may continue.
  • Your body is trying to adjust to being pregnant, so you may feel tired and want to rest more. 
  • The total amount of blood in your body increases.

Guide to prenatal care:

  • Visit your healthcare provider for one prenatal care checkup.
  • Eat a variety of healthy foods from the five major food groups: grains, fruits, vegetables; dairy, and meats/proteins.
  • You already should be taking prenatal vitamins. Your prenatal vitamin should contain 400 micrograms to 1 gram of folic acid.
  • Drink lots of fluids, at least six to eight glasses of water, juice, or milk every day.

MONTH 3 (9–12 weeks)

What happens to your baby?

  • Your baby's fingers and toes now have soft nails.
  • The mouth has 20 buds that will become baby teeth.
  • Fine hairs will begin to form on the baby's skin.
  • You can hear your baby's heartbeat for the first time (10 to 12 weeks) using a special instrument called a doptone.
  • All body organs will continue to mature, and your baby will gain weight.
  • Your baby will be 2.5–3 inches long and will weigh about 1 ounce by the end of the third month.

What happens to your body?

  • You may continue to feel tired and have morning sickness.
  • If headaches, lightheadedness, or dizziness persist or are severe, tell your healthcare provider.
  • You will feel your clothes getting tight around your waist and breasts. Try pullover tops and skirts or pants with elastic waists.

Guide to prenatal care:

  • Visit your healthcare provider for one prenatal checkup.
  • Your body will need an increased supply of all vitamins and minerals to nourish your baby. A healthy diet is important to meet these needs.
  • You may have gained 2–4 pounds by now. The amount of weight to be gained in your pregnancy depends on how much you weighed before getting pregnant. Usually, a woman who starts pregnancy at a normal weight may gain 25–35 pounds during pregnancy. Ask your healthcare provider how much weight you should gain.
  • Exercise can be beneficial; walking is a good activity. Always check with your healthcare provider before starting an exercise program.
  • Your healthcare provider will offer prenatal screening involving a nuchal translucency (NT) measurement and blood work between 11 and 13 weeks. Chorionic villus sampling (CVS) or other genetic testing may be offered to certain patients based on their ethnic background, personal history, or family history.

MONTH 4 (13–17 weeks)

What happens to your baby?

  • Your baby moves and swallows.
  • The skin is transparent and pink.
  • The umbilical cord continues to carry nourishment from mother to baby, which is why it is important to continue eating healthy. Remember: The umbilical cord also can pass along hazards like alcohol, nicotine, and other drugs, so DO NOT smoke, drink alcohol, or take drugs. Ask your provider about any medications you may want to take.
  • Your baby will be about 6–7 inches long and will weigh about 4–5 ounces.

What happens to your body?

  • Your appetite will increase and morning sickness will go away. You should begin to feel more energetic. However, it is not unusual to get headaches early in pregnancy. Ask your provider if you are concerned about headaches.
  • Toward the end of the fourth month (16 to 20 weeks), you may feel your baby move for the first time (this is called quickening); tell your healthcare provider.
  • Your belly begins to show-you probably will need maternity clothes and bigger bras now.

Guide to prenatal care:

  • Visit your health care provider for one prenatal care checkup.
  • Some pregnant women need extra iron, so your doctor may recommend iron supplements.
  • You will probably gain about a pound a week or 12–14 pounds, during the second trimester (months 4–6).
  • Your healthcare provider may offer a quad screen or amniocentesis between 15 and 21 weeks.

MONTH 5 (18–22 weeks)  

What happens to your baby?

  • Your baby becomes more active, turning from side to side and sometimes head over heels.
  • You might see finger and toe prints.
  • Your baby sleeps and wakes at regular intervals.
  • Your baby grows rapidly. At the end of the fifth month, your baby is about 10 inches long and weighs 1/2 to 1 pound.

What happens to your body?

  • If you haven't felt your baby move prior to this, you will begin to feel your baby moving. Tell your healthcare provider the day you are aware of fetal movement.
  • Your uterus has grown to the height of your belly button.
  • Your heart beats much faster.
  • You may need eight or more hours of sleep each night and during the day. Take rest breaks, if tired; don't push yourself.

Guide to prenatal care:

  • Visit your healthcare provider for one prenatal care checkup.
  • If you are smoking, drinking, or taking drugs, your baby's growth and weight gain can be affected. Remember: It's never too late to quit.
  • Eat a healthy, nutritious diet, and drink lots of juice, water, and milk every day.
  • You will have an ultrasound to evaluate your baby's anatomy.

MONTH 6 (23–27 weeks)

What happens to your baby?

  • The skin is red and wrinkled and now covered with fine, soft hair.
  • The shut eyelids now begin to part, and the eyes open.
  • The baby continues to grow rapidly. At end of the sixth month, the baby is about 12 inches long and weighs 1.5–2 pounds.

What happens to your body?

  • You now may feel the baby kicking strongly.
  • The skin on your growing belly may start to itch. Apply lotions to your body after you shower to lessen the itching.
  • Your back may hurt. Wear comfortable footwear — low-heeled shoes or flats — and no not stand for long periods of time. Exercise can help. You may feel pain down the sides of your belly; this is because as your uterus stretches, the ligaments that support it are being pulled on.

Guide to prenatal care:

  • Visit your healthcare provider for one prenatal care checkup.
  • You may be constipated. Drink more water or fruit juice, eat more foods with fiber (fruits, vegetables, and whole grains), and get some exercise, with your health care provider's approval. 
  • To help with heartburn, try eating four or five smaller meals during the day. You may also take TUMS, as directed on the bottle.
  • Do not use laxatives or antiacids without asking your healthcare provider.  
  • Most healthcare providers do a blood test for gestational diabetes (diabetes during pregnancy) at 24 to 28 weeks.

Labs tests

  • Glucose screen for gestational diabetes
  • CBC 
  • RPR 
  • HIV testing (with your consent)
  • If you are Rh negative, you will have an antibody screen and receive Rhogam

MONTH 7 (28–31 weeks)

What happens to your baby?

  • Your baby can open and close his/her eyes and suck his/her thumb.
  • The baby exercises by kicking and stretching.
  • The baby responds to light and sound.
  • The baby is now about 15–16 inches long and weighs about 2.5–3 pounds.

What happens to your Body?

  • If your ankles and feet swell from standing, lie down on your left side for an hour, and drink a glass of water. If you are concerned about the swelling, discuss this with your provider.
  • If you have new headaches and visual disturbances, along with excess weight gain and swelling, bring this to your provider's attention immediately. This may be a sign of increased blood pressure that might be dangerous to you and your baby.
  • As your belly and breasts get larger, stretch marks may appear. 
  • You may have contractions. These are normal, but call your healthcare provider if you have more than five contractions in one hour.
  • As your belly grows, you may lose your sense of balance. This makes it easier to fall. Be careful! 

Guide to prenatal care:

  • After the 28th week, visit your healthcare provider every two weeks for prenatal care.
  • Eat a variety of foods that are good for you. You should gain 1 pound a week this month.
  • Get plenty of rest — your body is working hard.
  • Start childbirth education classes if you haven't already done so. UI Health offers free childbirth education classes (in English and Spanish) to patients delivering at the University of Illinois Hospital. 

MONTH 8 (32–36 weeks)

What happens to your baby?

  • Rapid brain growth continues.
  • Your baby is too big to move around much, but she/he can kick strongly and roll around.
  • You may notice the shape of an elbow or heel against your abdomen.
  • Bones of the head are soft and flexible to make it easier for the baby to fit through the birth canal.
  • Fingernails have grown to the tips of fingers. Lungs still may be immature.
  • Your baby is now about 18–19 inches long and weighs about 4–5 pounds.

What happens to your body?

  • You may feel stronger contractions.
  • You should gain 1 pound a week.
  • You may have some leakage of colostrum (the fluid that will feed your baby until your milk comes in) from your breasts.
  • You may have trouble sleeping because it is hard to get comfortable. Try putting several pillows under your head, between your legs, or between your belly and your bed.
  • You may have shortness of breath as the baby crowds your lungs.
  • The baby may crowd your stomach. Try eating five or six smaller meals during the day.
  • The top of your uterus lies just under your rib cage.

Guide to prenatal care:

  • Visit your healthcare provider every two weeks for prenatal care checkups.
  • You will be screened for Group B Streptococcal (GBS) colonization after 35 weeks. This is a simple vaginal and rectal swab; it is not uncomfortable.
  • Call your healthcare provider right away if you have:  
    • Bleeding or a gush of fluid from your vagina
    • Cramps, stomach pains or a dull backache
    • Blurry vision, or spots before your eyes
    • A feeling that the baby is pushing down
    • A noticeable decrease in the baby's movements
    • More than five contractions in one hour
    • Headaches

MONTH 9 (37–40 weeks)

What happens to your baby?

  • Your baby is at full term at 37–40 weeks.
  • Your baby's lungs are mature. They are ready to function on their own.
  • Your baby gains about 1/2 pound a week.
  • This month your baby will drop into a head-down position and will rest lower in your abdomen.
  • The baby is 19–21 inches long and weighs 6–9 pounds.

What happens to your body?

  • Your belly button may stick out.
  • Your breathing becomes a lot easier once the baby drops, but you'll have to urinate more often because of pressure on your bladder.
  • Your ankles and feet may swell more. 
  • Your cervix will open up (dilate) and thin out (efface) as it prepares for birth.
  • You may be uncomfortable because of the pressure and weight of the baby. Rest as much as possible.

Guide to prenatal care:

  • After the 36th week, you have to visit your healthcare provider once a week for prenatal care checkups.
  • You may not gain any weight at all this month or may even lose 1 or 2 pounds.
  • You should have already decided whether you are going to breastfeed or formula-feed your baby.
  • Time your contractions. If you are in labor, you will have:
        • Regular or evenly spaced contractions (every seven minutes, for example)
        • Contractions will happen more than five times an hour
        • Each contraction will last for 30 to 70 seconds
        • They get worse as you move around

Call your health care provider if you think you are in labor.