Initial prenatal visit
Once your pregnancy has been confirmed, the prenatal period officially begins. Prenatal care involves a series of regular examinations and tests by a physician or midwife. In an uncomplicated pregnancy, most women will see their practitioner once a month until the 32nd week of pregnancy. At this point, you will be seen every two weeks. In the final month of pregnancy (37 weeks until delivery) your visits will be every week.
The prenatal period not only gives you time to get ready for the baby's arrival, but it is also an opportunity for you and your partner to get to know the people who will be directly involved during labor and delivery. The initial prenatal visit is often the longest. During this first visit, a complete physical examination along with a detailed family history and blood and lab work will be performed. The physician or midwife will calculate your baby's due date and that date will serve as a reference point in future visits when the baby's growth is assessed.
During the first prenatal visit, the physical examination involves an overall assessment of your health. This includes an assessment of heart, lungs and thyroid function along with an examination to rule out any infection. Next, the doctor will perform an obstetrical exam that includes a look at your abdomen and measurement of the height of your uterus.
All prenatal visits include a measurement of your weight, recording of your blood pressure and urine testing. A series of blood tests are also performed during the initial prenatal visit. The blood and laboratory tests that are most often recommended during the first visit may include:
Hemoglobin: This test checks your blood to determine if you are anemic (do not have enough iron in your blood). Women usually become slightly anemic as the pregnancy progresses, but very low levels of iron will need to be treated.
Blood type and RH with antibody screening: This test determines your blood RH type and antibody factor. If your blood type is RH negative and your partner's is RH positive, special monitoring of the fetus is necessary to check for RH incompatibility.
Rubella titer: This test checks the level of antibodies to the German measles virus that are present in your blood. If a woman becomes infected with German measles (rubella) during her pregnancy, her developing fetus could be at risk.
Syphilis screen: This test checks for the presence of syphilis infection. If present, treatment can be initiated so that the fetus is not harmed.
Hepatitis B screen: This test checks for infection with the Hepatitis B virus, which can be passed to an unborn child.
HIV screen: This test checks for the AIDS virus. If you have HIV infection, you can be treated during pregnancy, which will reduce the chances of your passing the virus to your unborn child.
PAP smear: This test checks for abnormal cervical cells, which could indicate cervical cancer.
Gonorrhea and Chlamydia cultures: Both of these infections must be treated to prevent infection of the baby at birth.
Urinalysis: This test examines the urine for the presence of bacteria, sugar or protein. It is usually performed at each prenatal visit.
Subsequent prenatal visits
Subsequent prenatal visits are usually shorter than the initial visit. During each visit your weight will be recorded. You may gain about 10 to 12 pounds in the first half of pregnancy and another 15 to 17 pounds during the second half. Experts believe that a sensible and safe weight gain during pregnancy is 25 to 35 pounds.
A blood pressure measurement also is recorded at each visit. Sudden rises in blood pressure can indicate complications during pregnancy.
Urine testing is performed at all prenatal visits. Specifically, the urine is checked for the presence of sugar and protein. Sugar in the urine could indicate gestational diabetes and the presence of protein could indicate toxemia, a pregnancy complication.
Your physician or midwife will measure the height of your uterus during each visit. As the baby grows, the fundus or top of the uterus begins to rise in the abdomen. By comparing the monthly or weekly measurements, your practitioner can evaluate the overall growth of the baby. Toward the later part of your pregnancy, your practitioner will check the baby's positioning by feeling around your abdomen and identifying different parts of the baby's body. As your baby's due date approaches, your practitioner may perform an internal examination to look for signs that labor is getting closer.
Each prenatal visit also should include a discussion about how you feel overall and whether or not you have any concerns. Your practitioner will probably ask you specific questions about symptoms such as headaches, visual problems, dizziness or swelling of the ankles, face and hands. Any of these symptoms could indicate a pregnancy complication. Also, your practitioner will check to be sure that you do not have any vaginal bleeding or abdominal cramping.
Somewhere between nine to 12 weeks of pregnancy, the baby's heartbeat can be heard with a special device called a doppler. The fetal heart tones, once identified, are recorded at each visit.
As your pregnancy advances, the following blood and laboratory tests most likely will be recommended:
Maternal Alpha-Fetoprotein (AFP) or expanded Alpha-fetoprotein testing which also includes measurements of estriol and HCG: AFP is often elevated in the blood of mother carrying a baby with a neural tube defect in which the spinal cord does not close normally. The American College of Obstetricians and Gynecologists (ACOG) now recommends that neural tube screening be offered in the mid-trimester for women who get only first trimester screening for Down Syndrome. (See below) If the AFP is low and if the other tests are low and high, respectively, an increased risk of Down's syndrome is present. Remember, this blood test only tells you if you are at risk for having a baby with any of these disorders. Follow-up testing is needed to confirm neural tube defects or chromosome disorders. Much controversy surrounds AFP testing because the test can produce many false-positive results. At times, woman carrying normal fetuses might get false results. Your health care provider will urge you to get more testing to see if the initial AFP screening is correct. It is best to talk to your practitioner about your individual risks and concerns regarding AFP testing, before consenting to this blood test.
Diabetes screening: During the 24th to 28th week of pregnancy (earlier for at-risk women), a glucose tolerance test is usually performed. Following a sugary drink, your blood sugar level is measured to check for a condition of pregnancy called gestational diabetes. If gestational diabetes is present, special efforts will be necessary to keep your blood sugar at a normal level. This can often be done with dietary restrictions but may, at times, require you to take insulin. In the vast majority of cases, gestational diabetes goes away following delivery, although women who develop diabetes during pregnancy should be monitored later in life for the development of diabetes.
Hemoglobin: Most practitioners will recommend a repeat screening to check you again for evidence of anemia between the 26th and 28th week of pregnancy.
Group B streptococcus swab: This test involves a culture of the lower vagina to check for the presence of strep B infection. It is usually performed toward the end of pregnancy between the 32nd and 36th week. If the infection is present, you can be treated during labor to prevent infection of the baby during the birthing process.
Other diagnostic tests sometimes used during pregnancy
Medical technology has made significant advances during the last 30 years. It is now possible to detect potentially serious problems in a developing fetus prior to birth. Your practitioner will take many factors into consideration before advising you to undergo additional testing in pregnancy. Some of these considerations include your age, pre-existing health problems, experiences and outcomes of previous pregnancies, history of genetic or congenital disorders, presence of multiple fetuses or other high-risk conditions during pregnancy.
All decisions to undergo diagnostic testing during pregnancy should be made jointly by both the parents and the practitioner. Before consenting to any procedure, you should feel comfortable that all of your questions have been satisfactorily answered and the risk and benefit of each test has been thoroughly explained.
The most common diagnostic tests used in pregnancy include:
Ultrasound: An ultrasound or sonogram test is often recommended at various stages throughout pregnancy. It allows the practitioner to evaluate the fetus at different stages of development. An ultrasound exam uses high-frequency sound waves to create a visual image of the fetus. Ultrasound exams are considered noninvasive, and they do not involve any exposure to radiation. During the test, a special gel is applied to your abdomen and a transducer is then placed on the belly so that sound waves can be conducted directly into the uterus. Often, pictures of the developing fetus are printed and given to the parents. Sometimes the sex of the fetus can be determined during an ultrasound procedure. Many practitioners are now routinely recommending ultrasound to monitor otherwise normal pregnancies.
Amniocentesis: Amniocentesis is a procedure in which amniotic fluid is taken from the uterus using a long needle that is inserted through the abdominal wall. It is currently the most popular technique used to screen for genetic and chromosomal disorders. Amniocentesis is preceded by an ultrasound exam to determine the baby's position and the location of pockets of amniotic fluid. Once the amniotic fluid is obtained, the cells are cultured and stimulated to grow for one to two weeks. After that, the cell chromosomes can be examined and test results determined. Amniocentesis does carry a slight risk of miscarriage (about one in 200) so the risk/benefit ratio of the test must be considered before consenting to this procedure.
In the past, practitioners had routinely offered Down Syndrome screening to pregnant women age 35 and older because they have an increased risk of having a baby with Down Syndrome. Now, ACOG recommends that all pregnant women be offered the opportunity to have their unborn child screened for Down Syndrome. This must be done in the first trimester (before the 20th week) of pregnancy.
Nuchal translucency scan. This test measures the amount of fluid in the back of the baby's neck. This is done in the first trimester at 11 to 14 weeks. A calculation is done using the fluid measurement, your age and the presence or absence of the baby's nasal bone to determine if there are any chromosomal abnormalities. The test also confirms the pregnancy, how far along you are and how many babies you are expecting.
Quad screen. This measures the levels of AFP, HCG, estriol, and inhibin A in your blood - proteins and hormones that only babies make. They pass through the placenta into your bloodstream. These levels are tested to see if they are normal, high or low. Many factors, including your weight, race, age and these tests help calculate whether or not the baby can have a chromosomal abnormality or neural tube defect. However, the results are not 100 percent accurate.
Chorionic villus sampling (CVS): CVS was developed in the 1970s as an alternative to amniocentesis to detect genetic or chromosomal abnormalities. It can be performed earlier in the pregnancy (usually between the 9th and 13th week) than amniocentesis, thus providing earlier results. CVS involves the sampling of chorionic cells (obtained either by placing a catheter through the cervix or through the abdominal wall) that can provide a complete picture of the genetic make-up of the developing fetus. CVS does slightly increase the risk of both miscarriage and infection, so it is important to weigh the risk/benefit ratio before consenting to this procedure. Your practitioner can help you in evaluating your individual risk for genetic or chromosomal abnormalities.
Non-stress test (NST): During a NST, the fetal heart rate is observed by hooking you up to a fetal monitor, Evidence of accelerations in the heart rate that correlate with fetal movement are looked for. A reactive tracing in which the heart rate of the fetus varies is considered a good finding. A NST may be recommended when a woman notices a decrease in fetal movement or when the due date has passed.
Stress test (OCT): The oxytocin challenge test is usually performed when results of the stress test are questionable. This test is very similar to the non stress test, except that you are given a small amount of medication to induce uterine contractions. The purpose of the OCT is to see how the fetus will respond to the normal stresses of labor.
Bio-physiological profile: This test is also used to determine fetal well-being. It involves an ultrasound examination of the fetus to determine the type of fetal movement and muscle tone that is present, along with the amount of amniotic fluid
Fetoscopy: This invasive test involves the insertion of a lighted instrument through the abdomen and uterus into the amniotic sac, where the fetus can be seen and photographed. The risk of fetal loss is estimated to be three percent to five percent. Therefore, the test is indicated only for those women who will benefit from having a fetal disorder identified and possibly treated during pregnancy.
Percutaneous umbilical cord sampling (PUBS): This test involves the removal of blood from the umbilical cord for further study. It is performed under ultrasound guidance and makes it possible to detect several blood diseases not detectable by amniocentesis.
Although the vast majority of pregnancies do not have complications, a small percentage of women do experience problems. Special testing during pregnancy often can identify problems early on, when effective treatment could resolve the problem. If your practitioner recommends any special testing in pregnancy, don't be afraid to ask questions about the test and the risk involved to both you and baby. The more information that you have, the better you will feel about making a decision to undergo testing during your pregnancy.
This article was reviewed and updated June 2007.
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