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.

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)
• Having contact with people who have rubella (German measles) and some other infections, which 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 Pregnancy at High-Risk: Risk Factors Present Before 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. She can also start taking prenatal multivitamins containing folate (folic acid). 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 (see Genetic Disorders Detection: Genetic Screening).

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.

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

• Measurement of weight, height, and blood pressure
• 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. Blood type, including Rh factor status (positive or negative), is determined.
• Urine tests: A sample of urine is taken, cultured, 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. If the woman has Rh-negative blood, it is tested for antibodies to the Rh factor (see Complications of Pregnancy: Rh Incompatibility). Having Rh antibodies can cause severe problems (even death) for a fetus that has Rh-positive blood. If antibodies in a pregnant woman's blood are detected early, the doctor can take measures to protect the fetus.

Did You Know... Things to avoid during pregnancy include tobacco, second-hand smoke, drugs, alcohol, cats, 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. 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.

Follow-up Examinations: After the first examination, a pregnant woman should see her doctor 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 heartbeat of the fetus is also checked to determine whether it is normal. The woman's ankles are examined for swelling.

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. This test is also done as soon as possible and preferably before 20 weeks for women who

• Are severely overweight (> 250 pounds)
• Have had a history of gestational diabetes
• Have polycystic ovary syndrome with insulin resistance (see see Menstrual Disorders and Abnormal Vaginal Bleeding: Polycystic Ovary Syndrome)

If the initial test is negative, these women should be retested at 26 to 30 weeks. All other women should have a screening blood test for diabetes at around 28 weeks of pregnancy.

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 (see Complications of Pregnancy: Preeclampsia).

If women have a high risk of conceiving a baby with a genetic disorder, prenatal diagnostic testing can be done (see Genetic Disorders Detection: Prenatal Diagnostic Testing).

Most doctors believe that ultrasonography (see see Common Imaging Tests: 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. 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.

Ultrasound Scanning in Pregnancy: Technique

Ultrasonography can show the fetus's beating heart at 6 weeks of pregnancy and thus can confirm that the fetus is alive. Doctors may periodically use an ultrasound device to listen to the fetus's heartbeat. Or they may use a stethoscope designed to listen to a fetus's heartbeat (fetoscope). The fetoscope can detect the heartbeat as early as 18 to 20 weeks of pregnancy.

Ultrasonography can also be used to do the following:

• Identify the sex of the fetus at 14 weeks of pregnancy
• See whether a woman is carrying more than one fetus
• Identify abnormalities, such as a mislocated placenta (placenta previa) or an abnormal position of the fetus
• Date the pregnancy and thus help determine whether the pregnancy is progressing normally
• Identify birth defects (sometimes)
• 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.

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

Last full review/revision November 2007 by Haywood L. Brown, MD