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Medical Care During Pregnancy


Raul Artal-Mittelmark

, MD, Saint Louis University School of Medicine

Last full review/revision May 2021| Content last modified May 2021
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Ideally, a couple who is thinking of having a baby should see a doctor or other health care practitioner to discuss whether pregnancy is advisable. Usually, pregnancy is very safe. However, some disorders can become severe during pregnancy. Also, for some couples, the risk of having a baby with a hereditary disorder is increased.

As soon as a couple is thinking of having a baby, the woman should start taking a multivitamin that contains folate (folic acid) once a day. The lowest amount recommended for women of childbearing age is 400 micrograms, but some experts recommend taking slightly higher amounts, such as 600 or 800 micrograms. Such doses are often available in over-the-counter products, such as multivitamins. Folate reduces the risk of having a baby with a birth defect of the spinal cord or brain (neural tube defect). Women who have had a baby with a neural tube defect should start taking a much larger amount than usually recommended: 4,000 micrograms as soon as they start thinking of having another baby. Doses of 1,000 micrograms or higher are available only with a prescription.

Did You Know...

  • Women who are thinking of becoming pregnant should start taking a multivitamin that contains folate (which helps prevent certain birth defects) rather than waiting until they are pregnant.

If the couple decides to try to have a baby, they and the doctor discuss ways to make the pregnancy as healthy as possible. The woman should ask the doctor about factors that could impair her health or the health of the developing fetus.

Factors or situations to avoid include the following:

  • Using tobacco or alcohol

  • Being exposed to secondhand smoke, which may harm the fetus

  • Having contact with cat litter or cat feces unless the cats are strictly confined to the home and are not exposed to other cats (such contact can transmit toxoplasmosis, an infection by a protozoan that can damage the fetus’s brain)

  • Being exposed to hot temperatures for a long time

  • Being exposed to chemicals or paint fumes

  • Having contact with people who have rubella (German measles) or other infections that can cause birth defects

  • Having contact with people who have chickenpox or shingles unless the woman has had a test that shows she has had chickenpox and is immune to it

Chickenpox and shingles are caused by herpes viruses. During delivery, these viruses can be spread to the fetus and cause severe illness. The virus can also cause pneumonia, which is occasionally severe, in the woman.

Knowing about and dealing with such factors before pregnancy may help reduce the risk of problems during pregnancy (see High-Risk Pregnancy). In addition, the woman can discuss her diet and her social, emotional, and medical concerns with the doctor.

When a woman sees a doctor or another health care practitioner before she is pregnant, she can be given any needed vaccines, such as the rubella vaccine. If she is not already taking folate, doctors can prescribe prenatal multivitamins that contain the recommended daily amount (RDA) of folate or a larger amount of folate if the woman has had a baby with a neural tube defect. If needed, genetic screening can be done to determine whether the woman and her partner are at increased risk of having a baby with a hereditary genetic disorder.

First examination

After pregnancy is confirmed, the woman should have a physical examination, preferably between 6 and 8 weeks of pregnancy. At this time, the length of the pregnancy can be estimated and the date of delivery can be predicted as accurately as possible.

Doctors ask about disorders the woman has and has had, drugs she taken, and details about previous pregnancies, including problems that occurred such as diabetes, miscarriages, and birth defects. Many doctors routinely ask women about domestic violence—whether she is being mentally, physically, or sexually abused by someone she lives with.

The first physical examination during pregnancy is very thorough. It includes the following:

  • Measurement of weight, height, and blood pressure

  • Examination of the ankles for swelling

  • Pelvic examination: During this examination, the doctor notes the size and position of the uterus.

  • Blood tests: A sample of blood is taken and analyzed. Analysis includes a complete blood cell count, tests for infectious diseases (such as syphilis, hepatitis, and human immunodeficiency virus [HIV]), and tests for evidence of immunity to rubella and chickenpox (varicella). Blood type, including Rh factor status (positive or negative), is determined.

  • Urine tests: A sample of urine is taken and analyzed.

  • Papanicolaou (Pap) test or a variation of it: Samples of tissue from the cervix are taken to check for cancer of the cervix.

  • Test for sexually transmitted diseases: Immediately after the Pap test, another sample of tissue from the cervix is taken to test for sexually transmitted diseases, such as gonorrhea and chlamydial infection.

Other tests may be done, depending on the woman’s situation. Thyroid hormone levels may be measured in some women (such as those with who have had a thyroid disorder, diabetes, infertility, or miscarriage).

If the woman has Rh-negative blood, it is tested for antibodies to the Rh factor (see Rh Incompatibility). The woman's immune system produces these antibodies when her Rh-negative blood comes in contact with Rh-positive blood—for example, in a previous pregnancy with a fetus who has Rh-positive blood. The antibodies (called Rh antibodies) may destroy blood cells in a fetus with Rh-positive blood, causing severe problems (even death) for the fetus. If antibodies in a pregnant woman’s blood are detected early, the doctor can take measures to protect the fetus. All women with Rh-negative blood are given Rh(D) immune globulin, injected into a muscle, at 28 weeks of pregnancy. They are also given an injection after any possible contact between their blood and the fetus's blood—for example, after an episode of vaginal bleeding or amniocentesis and after delivery. Rh(D) immune globulin reduces the risk that the fetus's blood cells will be destroyed.

Did You Know...

  • Things to avoid during pregnancy include tobacco, second-hand smoke, drugs, alcohol, cat litter and feces, and contact with people who may have chickenpox or shingles.

  • During the flu season, all pregnant women should get a flu shot.

Women of African descent are tested for sickle cell trait or disease if they have not been tested previously. Skin tests for tuberculosis are advisable for all women.

Follow-up examinations

After the first examination, a pregnant woman should see her doctor as follows:

  • Every 4 weeks until 28 weeks of pregnancy

  • Then every 2 weeks until 36 weeks

  • Then once a week until delivery

At each examination, the woman’s weight and blood pressure are usually recorded, and the size of the uterus is noted to determine whether the fetus is growing normally. The woman’s ankles are examined for swelling.

Doctors check the heartbeat of the fetus. It can usually be detected at about 10 to 11 weeks with a handheld Doppler ultrasound device. Once a heartbeat has been detected, doctors check it at each visit to determine whether it is normal.

At each visit, urine is tested for sugar. Sugar in the urine may indicate diabetes. If the urine contains sugar, a blood test to check for diabetes is done as soon as possible. Even if the urine does not contain sugar, doctors usually test all women for the type of diabetes that develops during pregnancy (gestational diabetes). This blood test is done at 24 to 28 weeks. It measures the level of sugar (glucose) in the blood 1 hour after women drink a liquid that contains a certain amount of glucose—called a glucose tolerance test. If women have risk factors for gestational diabetes, this test is done early in the pregnancy, preferably before 12 weeks.

Risk factors for gestational diabetes include the following:

  • Severe overweight (weighing more than 250 pounds)

  • Gestational diabetes or a large baby (weighing 10 pounds or more) in a previous pregnancy

  • An unexplained miscarriage in a previous pregnancy

  • First-degree relatives (such as mothers or sisters) with diabetes

  • A history of having sugar in the urine over a long period of time

  • Polycystic ovary syndrome with insulin resistance

If results of the initial test are normal, these at-risk women are retested at 24 to 28 weeks.

At each visit, the urine is also tested for protein. Protein in urine may indicate preeclampsia (a type of high blood pressure that develops during pregnancy).

Blood tests to check for thyroid disorders is done if women

  • Have symptoms of a thyroid disorder

  • Come from an area where moderate to severe iodine insufficiency occurs

  • Have relatives who have had a thyroid disorder

  • Have had a thyroid disorder

  • Have type 1 diabetes

  • Have had infertility problems, early delivery of a baby, or a miscarriage

  • Have had head or neck radiation therapy

  • Are severely obese

  • Are over 30 years old

If women have a high risk of conceiving a baby with a genetic disorder, prenatal diagnostic testing can be done.


Most doctors believe that ultrasonography, the safest imaging procedure, should be done at least once during a pregnancy to make sure the fetus is normally formed and to verify the expected date of delivery. It is usually done between 16 and 20 weeks of pregnancy.

For the procedure, a device that produces sound waves (transducer) is placed on the woman’s abdomen. The sound waves are processed to form an image that is displayed on a monitor. Sometimes, particularly during early pregnancy, the doctor uses an ultrasound device that can be inserted in the vagina. Ultrasonography produces high-quality images, including live-action images that show the fetus in motion. These images provide the doctor with useful information and can reassure a pregnant woman.

Ultrasonography can also be used to do the following:

  • Show the fetus’s beating heart and thus confirm that the fetus is alive, as early as 5 weeks of pregnancy

  • Identify the sex of the fetus, as early as 14 weeks of pregnancy

  • See whether a woman is carrying more than one fetus

  • Identify abnormalities, such as a mislocated placenta (placenta previa), too much fluid in the sac that contains the fetus (polyhydramnios ), or an abnormal position of the fetus

  • Date the pregnancy and thus help determine whether the pregnancy is progressing normally

  • Identify birth defects (sometimes)

  • Check for evidence of Down syndrome (and some other disorders) by measuring the fluid-filled space near the back of the fetus’s neck (called nuchal translucency)

  • Guide the placement of instruments during certain procedures, such as prenatal diagnostic testing

Toward the end of pregnancy, ultrasonography may be used to identify premature rupture of the fluid-filled membranes containing the fetus. Ultrasonography can provide information that helps doctors decide whether cesarean delivery is needed.

Other imaging

X-rays are not routinely taken during pregnancy, but they can be taken safely when necessary. If an x-ray is required, the fetus is shielded by placing a lead-filled garment over the woman’s lower abdomen to cover the uterus.


Experts recommend that all pregnant women be vaccinated against the influenza virus during the influenza (flu) season.

Pregnant women can be given the hepatitis B vaccine if needed.

Experts recommend a booster shot for tetanus, diphtheria, and pertussis (Tdap) after 20 weeks of pregnancy (preferably at 27 to 36 weeks) or after delivery, even if the shots are up-to-date.

Although the COVID-19 vaccine has not been specifically evaluated in pregnant women, experts recommend that the COVID-19 vaccine can be given to pregnant women who are eligible for vaccination and who have no contraindications to the vaccine, such as allergy to a component of the vaccine. No vaccines have been fully approved by the U.S. Food and Drug Administration (FDA), but some have been authorized for emergency use. (See also the Centers for Disease Control and Prevention: COVID-19 Vaccination.)

The measles, mumps, and rubella vaccine and varicella vaccine should not be given during pregnancy.

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