A normal pregnancy lasts nine months. Each three-month period of pregnancy is called a trimester. During each trimester, the fetus grows and develops. Regular medical checkups and prenatal tests are very important. They can:

• Help keep you and your baby healthy
• Spot problems with your baby (if there are any). In some cases, health care professionals can treat the problem before your baby is born. But even when they cannot, it can still be helpful to know about the problem early on. That gives you time to learn about your baby's condition and prepare for any challenges you may face after the baby is born.
• Prevent problems during delivery. For example, if your baby is breech (bottom first or feet first, instead of head first), you may need to have a Cesarean section to avoid complications.

Besides getting medical care, there are other things you can do to keep your baby as healthy as possible. It's important not to drink or smoke. Try to eat a healthy diet and make sure to take care of any health problems you have during pregnancy.

You should start taking care of yourself before you start trying to get pregnant. This is called preconception health. It means knowing how health conditions and risk factors could affect you or your unborn baby if you become pregnant. For example, some foods, habits, and medicines can harm your baby — even before he or she is conceived. Some health problems also can affect pregnancy.

Talk to your doctor before pregnancy to learn what you can do to prepare your body. Women should prepare for pregnancy before becoming sexually active. Ideally, women should give themselves at least 3 months to prepare before getting pregnant.

The five most important things you can do before becoming pregnant are:

1. Take 400 to 800 micrograms (400 to 800 mcg or 0.4 to 0.8 mg) of folic acid every day for at least 3 months before getting pregnant to lower your risk of some birth defects of the brain and spine. You can get folic acid from some foods. But it's hard to get all the folic acid you need from foods alone. Taking a vitamin with folic acid is the best and easiest way to be sure you're getting enough.
2. Stop smoking and drinking alcohol. Ask your doctor for help.
3. If you have a medical condition, be sure it is under control. Some conditions include asthma, diabetes, depression, high blood pressure, obesity, thyroid disease, or epilepsy. Be sure your vaccinations are up to date.
4. Talk to your doctor about any over-the-counter and prescription medicines you are using. These include dietary or herbal supplements. Some medicines are not safe during pregnancy. At the same time, stopping medicines you need also can be harmful.
5. Avoid contact with toxic substances or materials at work and at home that could be harmful. Stay away from chemicals and cat or rodent feces.

Throughout this section, fetal development is described in terms of number of weeks from conception and number of weeks from last menstrual period (LMP); LMP is the description medical providers commonly use when calculating a due date.

2 weeks after conception
(4 weeks after the last menstrual period)

• The embryo is about 1/100 of an inch long.
• The ball of cells collapses and begins to form cell layers.

4 weeks after conception
(6 weeks after the last menstrual period)

• The embryo is about 1/6 inch long.
• Structures that will become arms and legs (limb buds) begin to appear.
• The circulatory system begins to form. The heart is pumping blood and the rate can be measured by ultrasound.
• In the fifth week, the neural tube forms, which later will become the spinal cord and brain.

6 weeks after conception
(8 weeks after the last menstrual period)

• The embryo is now about ½ to 5/8 inches long.
• Eyes, ears, and facial features begin to develop.
• Fingers and toes are more distinct.

8 weeks after conception
(10 weeks after the last menstrual period)

• The embryo has matured and is referred to as a fetus for the rest of the pregnancy.
• The fetus is about 1¼ - 1 ½ inches long from crown to rump.
• Muscles and skeleton are developing and the nervous system becomes mature enough that reflex activity may occur.
• The beginnings of all the key body parts and organs are present, although they are immature and not completely positioned in their final locations.
• The fetal heartbeat can be heard with an electronic monitoring device.

10 weeks after conception
(12 weeks after the last menstrual period)

• The fetus is about 2½ inches long from crown to rump and weighs 1/3 to ½ ounce.
• The fetus makes small, random movements, too small to be felt.
• The eyelids form and cover the eye. The eyes remain closed for now.
• The fingernails appear on the digits.

12 weeks after conception
(14 weeks after the last menstrual period)

• The fetus is about 3 ½ inches long from crown to rump and weighs about 1 ounce.
• Swallowing movements begin.
• The kidneys begin to make small amounts of urine.
• External genitalia are now formed. An ultrasound may possibly identify the sex of the fetus at this time.

Throughout this section, fetal development is described in terms of number of weeks from conception and number of weeks from last menstrual period (LMP); LMP is the description medical providers commonly use when calculating a due date.

14 weeks after conception
(16 weeks after the last menstrual period)

• The fetus is about 4 ¾ inches from crown to rump and weighs about 3 ½ ounces.
• The head is more erect and the arms and legs are developed.
• Limb movements become more coordinated because joints will now function.

16 weeks after conception
(18 weeks after the last menstrual period)

• The fetus is about 5 ½ inches long from crown to rump and weighs between 6 and 7 ounces.
• The skin is transparent. Blood vessels are very easily seen through the skin.
• Hair and nails begin to grow.
• The fetus can now blink, grasp, and move the mouth.

18 weeks after conception
(20 weeks after the last menstrual period)

• The fetus is about 6 ½ inches long from crown to rump and weighs about 10 ounces.
• All organs and structures have been formed and a period of simple growth begins.
• The skin is covered by vernix, a waxy substance that protects the skin.
• Most women feel the fetus moving or kicking.
• The sex of the fetus can now often be more readily identified by ultrasound.
• Some experts have concluded the fetus is capable of feeling physical pain at about this time of development; other experts have concluded the fetus feels pain during later stages of development. This issue can be explored in the reference section of this website.

20 weeks after conception
(22 weeks after the last menstrual period)

• The fetus is about 7 ½ inches long from crown to rump and weighs from 14 to 16 ounces (1 pound).
• The fetus is more active, kicking, sucking, and turning in the uterus.
• A period of extremely rapid brain development is beginning.
• The eyelids, eyebrows, and fingernails are well developed.
• Survival rates for fetuses born at 22 weeks' gestation are low.

22 weeks after conception
(24 weeks after the last menstrual period)

• The fetus is about 8 ½ inches long from crown to rump and weighs about 1 ¼ pounds.
• The bones of the ears harden, enabling sound conduction. The fetus can now hear voices or sounds of its mother's breathing or heartbeat.
• The proportions of the face and body begin to assume the appearance of an infant near its due date.
• A period of substantial weight gain is beginning; fat layers are starting to form.
• Lungs are still immature; a fetus born at this time will attempt to breathe, but is not likely to survive without very intensive care. In Alaska, with optimal care, the survival rate of fetuses born at 23 weeks gestation is approximately 63%. If born at 24 weeks gestation, survival odds improve to 70%.

24 weeks after conception
(26 weeks after the last menstrual period)

• The fetus is about 9 inches long from crown to rump and weighs 1½ to 1 ¾ pound.
• The body is lean and the skin appears wrinkled due to the lack of body fat.
• With optimal care, survival is 80% likely for fetuses born at this gestational age.

Throughout this section, fetal development is described in terms of number of weeks from conception and number of weeks from last menstrual period (LMP); LMP is the description medical providers commonly use when calculating a due date.

26 weeks after conception
(28 weeks after the last menstrual period)

• The fetus is about 10 inches long from crown to rump and weighs around 2 ½ pounds.
• The eyes can perceive light, eyes can open and eyelashes are now present.
• The woman may feel fetal respiratory movements as "hiccups".
• Although immature, an otherwise normal fetus born at this time will often survive with expert care. Around 90% of fetuses born at 28 weeks gestation can survive with good care.

28 weeks after conception
(30 weeks after the last menstrual period)

• The fetus is 10 ½ inches long from crown to rump and weighs almost 3 pounds.
• The lungs develop to the point where breathing air is possible, although help is usually needed. In Alaska, with good care, the survival rate is 96% or better for fetuses of 29 weeks gestation or more.

30 weeks after conception
(32 weeks after the last menstrual period)

• The fetus is about 11 inches long from crown to rump and generally weighs more than 3 pounds.
• The skin is pink and no longer so transparent.
• Toenails are now present.
• From this stage on, fetal development is essentially complete, and growth is the primary change noted.

32 weeks after conception
(34 weeks after the last menstrual period)

• The fetus is about 12 inches long from crown to rump and generally weighs 4 to 4 ½ pounds.
• Eyes close during sleep and open during alert times.
• The skin becomes smoother and pink.

34 weeks after conception
(36 weeks after the last menstrual period)

• The fetus is 13 inches long from crown to rump and generally weighs about 5 to 5½ pounds.
• Scalp hair is silky and lays against the head.
• Muscle tone improves so the fetus can turn and lift its head.

36 weeks after conception
(38 weeks after the last menstrual period)

• The fetus is 13 ½ inches long from crown to rump and generally weighs between 5 ½ to 6 ½ pounds.
• Lungs are usually mature.
• The fetus can grasp firmly.
• The fetus turns toward light sources.
• The fetus is gaining about ½ ounce per day.

38 weeks after conception
(40 weeks after the last menstrual period)

• The fetus averages 14 ½ inches from crown to rump and an average of 20 inches in length from head to toe.
• The average weight is around 7 ½ pounds.
• This is a "full-term" fetus ready to be born.

Follow these do's and don'ts to take care of yourself and the precious life growing inside you:

Health care do's and don'ts

• Get early and regular prenatal care. Whether this is your first pregnancy or third, health care is extremely important. Your doctor will check to make sure you and the baby are healthy at each visit. If there are any problems, early action will help you and the baby.
• Take a multivitamin or prenatal vitamin with 400 to 800 micrograms (400 to 800 mcg or 0.4 to 0.8 mg) of folic acid every day. Folic acid is most important in the early stages of pregnancy, but you should continue taking folic acid throughout pregnancy.
• Ask your doctor before stopping any medicines or starting any new medicines. Some medicines are not safe during pregnancy. Keep in mind that even over-the-counter medicines and herbal products may cause side effects or other problems. But not using medicines you need could also be harmful.
• Avoid x-rays. If you must have dental work or diagnostic tests, tell your dentist or doctor that you are pregnant so that extra care can be taken.
• Get a flu shot. Pregnant women can get very sick from the flu and may need hospital care.

Food do's and don'ts

• Eat a variety of healthy foods. Choose fruits, vegetables, whole grains, calcium-rich foods, and foods low in saturated fat. Also, make sure to drink plenty of fluids, especially water.
• Get all the nutrients you need each day, including iron. Getting enough iron prevents you from getting anemia, which is linked to preterm birth and low birth weight. Eating a variety of healthy foods will help you get the nutrients your baby needs. But ask your doctor if you need to take a daily prenatal vitamin or iron supplement to be sure you are getting enough.
• Protect yourself and your baby from food-borne illnesses, including toxoplasmosis (TOK-soh-plaz-MOH-suhss) and listeria (lih-STEER-ee-uh). Wash fruits and vegetables before eating. Don't eat uncooked or undercooked meats or fish. Always handle, clean, cook, eat, and store foods properly.
• Don't eat fish with lots of mercury, including swordfish, king mackerel, shark, and tilefish.

Lifestyle do's and don'ts

• Gain a healthy amount of weight. Your doctor can tell you how much weight gain you should aim for during pregnancy.
• Don't smoke, drink alcohol, or use drugs. These can cause long-term harm or death to your baby. Ask your doctor for help quitting.
• Unless your doctor tells you not to, try to get at least 2 hours and 30 minutes of moderate-intensity aerobic activity a week. It's best to spread out your workouts throughout the week. If you worked out regularly before pregnancy, you can keep up your activity level as long as your health doesn't change and you talk to your doctor about your activity level throughout your pregnancy. Learn more about how to have a fit pregnancy.
• Don't take very hot baths or use hot tubs or saunas.
• Get plenty of sleep and find ways to control stress.
• Get informed. Read books, watch videos, go to a childbirth class, and talk with moms you know.
• Ask your doctor about childbirth education classes for you and your partner. Classes can help you prepare for the birth of your baby.

Environmental do's and don'ts

• Stay away from chemicals like insecticides, solvents (like some cleaners or paint thinners), lead, mercury, and paint (including paint fumes). Not all products have pregnancy warnings on their labels. If you're unsure if a product is safe, ask your doctor before using it. Talk to your doctor if you are worried that chemicals used in your workplace might be harmful.
• If you have a cat, ask your doctor about toxoplasmosis. This infection is caused by a parasite sometimes found in cat feces. If not treated toxoplasmosis can cause birth defects. You can lower your risk of by avoiding cat litter and wearing gloves when gardening.
• Avoid contact with rodents, including pet rodents, and with their urine, droppings, or nesting material. Rodents can carry a virus that can be harmful or even deadly to your unborn baby.
• Take steps to avoid illness, such as washing hands frequently.
• Stay away from secondhand smoke.

Life is busy before a baby arrives. There are many things to do to prepare. One of the most important is to visit your health care provider regularly.

Check-ups before your baby is born are called prenatal visits. They help make sure you and your baby are healthy. Your health care provider will look for certain problems that can happen during pregnancy. Some issues are best treated early. Others can be prevented before they start.

“Prenatal care is fundamental for shaping the lives of women and their children,” says Dr. Monica Longo, an NIH expert on prenatal health. Longo cares for women with high-risk pregnancies. Such women have a higher chance of complications.

If you think you may be pregnant, schedule a visit with your provider. If you’re pregnant, you’ll need to start regular prenatal visits. Most women have check-ups about once a month in the beginning. Then, they go more often later in the pregnancy.

During a prenatal visit, your provider will ask about your health history. They will also perform a physical exam and weight check. They’ll let you know how much weight gain is healthy for your body and help track your progress.

You’ll also be asked to provide a urine sample. Urinary tract infections (UTIs) are common during pregnancy. UTIs and other infections increase the risk of having a preterm birth. This is when you give birth at 37 weeks or earlier.

“One of the primary purposes of prenatal care is actually prevention,” says Longo. “We screen women to find potential health problems before those issues can worsen.”

During certain stages of pregnancy, your provider will perform blood tests and imaging tests. These include ultrasound exams to look at the baby’s growth and development. Visits are also an opportunity to talk with your provider about how to give your baby a healthy start.

“During prenatal visits, we educ-ate and counsel moms about healthy habits, healthy food choices, and exercise,” Longo says. “We also address any concerns a new mom-to-be might have.”

Taking a prenatal vitamin is also key. Folic acid is included in most prenatal vitamins. It reduces the risk of severe birth defects that affect the developing brain and spine.

It’s important to stay away from things that could harm your baby. These include certain medications, smoking, and alcoholic drinks. Also, talk with your provider about any health conditions. Conditions like diabetes (a disease that causes high blood sugar) and high blood pressure need to be brought under control.

Some women choose to talk with their provider before becoming pregnant. This is called a preconception visit. It can help you plan for a safer pregnancy.

Early and regular care for you and your developing baby is important. Studies show that prenatal care reduces the risk of having a low-birth weight baby. Low birth weight can cause health problems. Even during the pandemic, it’s essential to keep up with regular prenatal care.

“Providers around the globe have adapted prenatal care to fit the current challenges,” says Longo. That means using telehealth for visits that don’t have to be done in person.

Health care providers are also seeing fewer patients and extending the time between them. This reduces possible exposure in waiting rooms.

“Providers are prepared for these difficult times,” says Longo. So it’s crucial that moms-to-be keep up with prenatal care.

Your First Prenatal Visit

Here’s what you can expect:

• Your doctor will ask about your health history. This includes diseases, operations, or prior pregnancies. They may also ask about your family’s health history.
• A complete physical exam. This includes a pelvic exam and Pap test, which checks for cells that are not normal in the lower part of the uterus.
• Getting your blood pressure, height, and weight taken.
• Giving blood and urine samples for lab work.
• Having your due date calculated.
• Time for questions. It can be helpful to bring a list of any questions you want to ask.