Prenatal Workup
Getting To Know You
Your official relationship with your doctor begins with the three-part prenatal workup. First, a medical history reveals any past or current health problems for you or in your immediate family that may affect your pregnancy. The questions are very standard, so don’t get excited when you’re asked if you mainline heroin or have syphilis. If you have any unusual (or what the “moral majority” might consider) unspeakable diseases or habits, don’t be embarrassed or withhold information. With few exceptions, health care providers are nonjudgmental or at least desensitized. The goal is to give you the best care possible and work with whatever problems exist, no matter what they are.
Next is a physical exam. Besides the usual poking, prodding, and stick out your tongue routine, your pelvis is evaluated for its potential as a gateway for your baby’s journey into the new world. Adequate and borderline are two terms commonly used. “Adequate” means that the baby should slip through without problems; “borderline” means wait and see: It might be a tight squeeze. If your doctor describes your pelvis as big as the Grand Canyon, consider it a compliment. But don’t get ugly and hateful if your doctor says “She has a pelvis I could deliver through” and you end up with a cesarean birth. It happens. Nothing is 100 percent guaranteed.
During the pelvic exam, your uterus is palpated (felt) to determine if the date of your last menstrual period (LMP) is consistent with the size of your uterus. The exam provides reference points to be sure that things are proceeding normally during the pregnancy and the baby is growing on schedule. If you’re unsure of your LMP, or have risk factors, an ultrasound may be done at or before 20 weeks’ gestation to more accurately pinpoint your due date. The distance from your pubic bone to the tip of the uterus (fundus) is measured in centimeters. The number of weeks you’re pregnant will approximate the size of your uterus; 20 weeks will equal 20 centimeters, give or take a centimeter. This is another way to follow your baby’s growth.
The last part of the workup includes lab tests done for the following various reasons.
Routine Tests
Blood Count (Hemoglobin and Hematocrit)
This test detects anemia. It is repeated around 28 weeks to monitor if blood volume has expanded adequately. Your hematocrit normally decreases during the second trimester from increased plasma volume and the slower increase in red cell production. The normal decrease is not synonymous with anemia. Since the decrease is a healthy sign, some practitioners argue against routinely giving iron supplements.
Urinalysis and Culture
This test screens for infection and other kidney disease since symptoms may not be present.
Blood Type and Rh Factor
This test establishes if there’s a risk for potential incompatibility and Rh disease.
Antibody Screen
Your body produces substances (antibodies) in response to exposure to other substances that are foreign to your body (antigens). Blood screening detects antibodies that may be harmful to your baby.
Rubella (Measles) Antibody Titer
This test determines if you’re immune to measles. Nonimmune rates in women are about 10 percent. Measles produce serious congenital deformities if the mother is infected during pregnancy. Immunization for nonimmune women is done after delivery.
Serology (VDRL)
This is the test for syphilis. The positive rate is very low, but testing is required by state law.
Blood Sugar
This test screens for potential gestational diabetes (pregnancy-induced glucose intolerance). Pregnancy is the perfect time to screen all women for diabetic tendency. The hormones of pregnancy inhibit insulin production, and a temporary diabetic condition can result. A meal high in carbohydrates or 50-gram glucose drink is taken and the blood sugar level tested in 1 or 2 hours.
Subsequent Visits
Office visits are monthly until 32 weeks, every 2 weeks until 36 weeks, and usually weekly during the last month. Your visits may be fairly brief, but they’re very important. Besides answering your questions, your doctor will evaluate and record several things, including:
- Blood pressure (BP). Normally your BP decreases by the second trimester. If your BP increases during the second trimester, it may be one of the signs of preeclampsia, a dangerous disease for both you and the baby.
- Weight. Your pattern of weight gain is important to your baby’s growth. Unusual weight gain, more than 2 pounds in 1 week, may be the first sign of preeclampsia.
- Uterine size. Your doctor measures the distance from your pubic bone to the top of your uterus. The measurement indicates if the baby is growing appropriately and helps detect the small for gestational age (SGA) and intrauterine growth retardation (IUGR).
- Fetal heart rate. Your doctor does this test routinely to reassure you and entertain the siblings. It’s a nice touch, but it doesn’t provide reliable information regarding the baby’s well-being. There’s no validity to predicting sex according to heart rate, which tends to be faster in early pregnancy and slows as the central nervous system matures. Usual heart rates are between 120 to160 beats per minute.
- Fetal movement. An active baby is usually a healthy baby. Try to become acquainted with your baby’s wake and sleep cycles (activity patterns). Your doctor will routinely ask if the baby moves a lot.
- Urine testing. Your urine is traditionally tested every visit for protein and sugar. Many normal pregnant women spill sugar into their urine. A blood sugar test is the preferred way to screen for diabetes. Protein is checked to detect preeclampsia, but weight gain and BP are earlier indicators of the presence of the disease.
Other Tests
Chlamydia
Chlamydia is a common sexually transmitted disease, with 3 million new infections occurring annually in the United States. There are no known adverse effects on pregnancy. Occasionally, the mother contracts a postpartum pelvic infection from chlamydia. The newborn baby whose mother has the chlamydia virus in her cervix can contract eye infections or pneumonitis after birth. Chlamydia, detected during pregnancy, can be treated effectively before delivery to eliminate the risk to the baby and mother.
Chicken Pox
Five percent of the adult population escaped contracting chicken pox as a child. Only one-fourth of adults with no history of having the virus are susceptible. A lab test will detect immunity if you’re uncertain whether you’ve had it. Chicken pox can be very serious in pregnancy. If you aren’t immuneand you’re exposed to the virus, you can be treated with zoster Immune globulin (ZIG) while pregnant. Talk to your doctor.
Cytomegalovirus (CMV) and Parvovirus
CMV exposure may occur in health care workers, school teachers, and day care providers. Parvovirus causes “Fifth disease,” which is a ‘fairly common viral illness in schoolchildren. If the mother contracts the infection during pregnancy, the risk to the baby is very small. If you’re exposed to either virus, tell your doctor who’ll advise you.
Human Immunodeficiency Virus (HIV)
HIV is a sexually transmitted disease that causes AIDS (acquired immunodeficiency syndrome). The virus attacks the body’s immune system, resulting in a loss of resistance to various infections. T he virus may be present in the blood many years before symptoms of AIDS develop. Ninety percent of AIDS cases have occurred in homosexual or bisexual men, intravenous drug users, and those who’ve received HIV-contaminated blood or blood products. In cities with a high rate of IV drug users, HIV in pregnant women is becoming more prevalent.
Obstetricians are concerned about HIV because the pregnant woman can unknowingly transmit the virus to her unborn child. If you’ve had sexual contact at some time with someone in the high-risk groups for carrying the AIDS virus, discuss your concerns with your physician.
Hepatitis B (serum hepatitis)
It’s possible to carry the hepatitis B virus and not have symptoms. The virus can be transmitted to the pregnant woman’s baby during delivery. When a pregnant woman is identified as a virus carrier, treatment can be given to the baby at delivery to prevent infection. Health care workers and Southeast Asians are considered at higher risk for being carriers of the virus. In some areas, hepatitis B testing is routine for all pregnant women. If you’re in the high-risk category, talk to your doctor.
Toxoplasmosis
If you’re a cat owner or work in the veterinary field, this one’s for you. Toxoplasmosis is an infection resulting from contact with airborne protozoa from cat feces or from eating contaminated raw or rare meat. The infection isn’t serious unless it’s the first occurrence and you’re pregnant. If you’re in the at-risk category, tell your doctor so she can test to see if you’ve had a previous infection. It’s nice to have reassurance that there’s no risk to your baby. Ideally, you should be tested before you become pregnant.