Your Guide to Prenatal Tests and Doctor Visits
You’re in for some serious poking and prodding. Over the next nine months, you’ll see your OB at least 10 times. Here’s what to expect at these visits. Photo: Shutterstock / The Bump
First Prenatal Visit
Even if you take a home pregnancy test or you miss your period, you probably won’t actually see your OB-GYN until around the eight-week mark. Here’s what exactly your OB will be testing for at your first visit:
Initial Blood Work: First things first -- your OB will take a small sample of blood for a long list of screenings. With it, she’ll determine your blood type, just in case you need a transfusion (very unlikely!) during pregnancy or delivery.
Your blood also will be tested for Rh, a protein present in about 85 percent of the population. If you’re Rh-negative, you’ll need injections of a medication called RhoGAM at 28 or 29 weeks, and about 72 hours before delivery, to prevent problems. That’s because if baby is Rh-positive and you’re Rh-negative, there’s a risk of complications.
In your initial blood work, your OB will also measure your levels of human chorionic gonadotropin, a hormone that indicates whether baby is developing well. Your doc will also look for abnormal hemoglobin levels or red or white cell counts, which can be a sign of anemia or infection. You'll also be screened for hepatitis B; syphilis, HIV and other STDs; and immunity to German measles.
Pap Smear: Your first prenatal visit will also include a Pap smear. If you usually get an annual checkup with the gynecologist, you know what this is: The doc will swab your cervix for cells and then test them for abnormalities, signs of cervical cancer, and STDs like chlamydia, HPV and gonorrhea.
Urine Tests: Get ready for lots of peeing in cups! At pretty much every appointment, you’ll provide a urine sample to be tested. The sample will be screened for glucose (elevated levels can be a sign of gestational diabetes) and protein (a possible indication of preeclampsia or a urinary tract infection). If either shows up in your urine, your doctor will likely order additional testing.
Other First Trimester Tests
Ultrasound: An ultrasound uses sound waves and echoes to create a moving image of your fetus and show what’s going on inside your womb. You’ll probably have at least two ultrasounds during your pregnancy. You may get more ultrasounds if there are any issues your doc needs to monitor. And if your doctor orders it, you might have a late-pregnancy ultrasound to check for preterm labor by measuring your cervix length.
At about 10 weeks, your OB will likely do an ultrasound to detect a fetal heartbeat and confirm that the pregnancy is uterine (as opposed to ectopic or tubular).
First Trimester Screen: This is administered between weeks 11 and 13, and includes two tests: a nuchal translucency screening (NTS) and a blood test, which will help determine your baby’s risk factor for Down Syndrome and other chromosomal problems.
The nuchal translucency screening is a special type of ultrasound in which your doc will measure baby’s neck (if the area is thicker than average, it could be a warning sign).
In the blood test, your blood will be screened for hCG and PAPP-A, two pregnancy hormones. Abnormally high or low levels could indicate a problem. Your doctor will combine your results from the NTS and the blood test with your age and determine your risk factor for chromosomal problems (1 in 1,000, for example). If the odds seem higher, you may be offered further testing, since there’s about a 5 percent false positive rate.
Chorionic Villus Sampling (CVS): This an optional test for genetic disorders that you can choose to get -- often parents-to-be choose to have a CVS done when one parent has a genetic disorder or one runs in the family. It’s normally done between weeks 10 and 12, and it can detect genetic disorders such as Tay-Sachs disease and sickle-cell anemia, and rule out chromosomal disorders like Down syndrome. The bonus: It also determines the baby’s gender with total accuracy.
In the CVS, you’ll first get an ultrasound to double-check how far along you are and determine the best way for your doctor to get a good sample of cells. It could be transabdominal (through the abdomen) -- with a needle through your belly and uterus to the placenta -- or transcervical -- with speculum inserted into your vagina. Keep in mind that CVS also increases the chances of developing a uterine infection, having a miscarriage (the risk is 1 in 400) or having a baby with arm or leg abnormalities (but this risk is very low).
During the second trimester, you’ll still see your doctor every four weeks. At every visit, you’ll get a urine test as usual. Here are the tests you can expect to get during the second trimester:
Midpregnancy Ultrasound: This is a more detailed ultrasound than the one you got in the first trimester; it’s also referred to as an anatomy scan or a level-two ultrasound. It’s usually performed between weeks 18 and 22. During the midpregnancy ultrasound, your baby will be measured from crown to rump and around his waist and head to confirm proper growth, and the ultrasound technician (and/or doc) will check his kidneys, bladder, stomach, brain, spine, sex organs and four chambers of the heart to make sure everything looks A-OK. The technician will also check amniotic fluid levels, placenta location and fetal heart rate. And, if you want to know, you’ll probably be able to find out baby’s gender!
Triple/Quad Screen Test: The triple screen and quad screen tests assess the probability of genetic disorders and chromosomal abnormalities like Down syndrome. It’s a blood screening that’s performed between the 15th and 20th weeks of pregnancy. You might choose to do this if you want a more accurate evaluation of your baby’s risk of neural tube defects than the first trimester screen offers.
The triple test looks for three things: AFP (alpha-fetoprotein, which is produced by the fetus), hCG (human chorionic gonadotropin, a hormone produced in the placenta) and estriol (an estrogen produced by the fetus and placenta). The quad screen looks for the same three things, as well as abnormal levels of Inhibin-A, which is a type of protein produced by the placenta and ovaries that could indicate baby’s risk for Down syndrome. Your doctor will use this test in conjunction with other factors, like your age and ethnicity, to decide if further testing should be done.
Amniocentesis: An amniocentesis is a test for genetic disorders (normally performed between week 14 and week 20). Your doctor may recommend you get an amnio if you get an abnormal triple or quad test result or if you have other genetic concerns about baby.
In an amniocentesis your doctor will use an ultrasound to guide a needle into a safe place in the amniotic sac and collect a sample of amniotic fluid. The procedure normally takes 45 minutes.
Amniocentesis can detect chromosome abnormalities, neural tube defects and genetic disorders. It also may be used in late pregnancy to see if the baby’s lungs are mature enough that he could breathe on his own. In general, amniocentesis is a safe procedure, but it does pose some risks. The risks of having an amniocentesis include miscarriage (very rare, about 1 in 200 to 1 in 400), cramping and vaginal bleeding, leakage of amniotic fluid, needle injury to fetus, Rh sensitization, and infection.
Cordocentesis: This is a diagnostic test (performed after 17 weeks into pregnancy) that examines blood from the fetus to check for chromosomal abnormalities. It’s different from an amniocentesis because it doesn’t test for neural tube defects. You might get a cordocentesis if you had an amniocentesis and the results were inconclusive. If you get one, you’ll get an ultrasound so the doctor can determine where the umbilical cord meets the placenta. Then the doctor will insert a needle into the umbilical cord to collect a blood sample. Note that there are a few risks to this test, including miscarriage (1 or 2 in 100 tests), blood loss, infection, premature rupture of membranes and drop in fetal heart rate.
Glucose Challenge Screening Test: The Glucose Challenge Screening Test is a blood screening that’s administered between weeks 24 and 28. In it, your doctor will gauge how effectively your body processes sugar, to see if you’re at risk for gestational diabetes mellitus. To do that, she’ll ask you to drink a sample of Glucola (a sweetened drink that contains 50 g of glucose), then an hour later, your blood will be drawn and its glucose levels will be tested. If there are signs you’re not processing the glucose normally, your doctor will likely order additional glucose testing (glucose tolerance test), in which your blood is drawn several times over the course of a few hours, to get a more accurate reading.
From weeks 28 to 36, you’ll visit your OB every two weeks. After that, you’ll see your doctor once a week. Again, you’ll give a urine sample at each visit. Here’s what other tests to expect during the third trimester:
Group B Strep Test: Around week 36, all moms-to-be get a group B strep test. The test screens for bacteria (called group B strep) in the rectum and vagina, which is harmless to you but can be dangerous if transmitted to baby during delivery. Your doctor will swab your vagina and rectum to get samples to be tested and likely will give you results within two days. If they do find group B streptococcus, you will be given antibiotics to fight the strep so baby isn’t exposed to it at birth.
Biophysical Profile: A biophysical profile is a combination of two tests: an ultrasound and a non-stress test, used to determine baby’s (or babies’) well-being. It is normally performed if you’re carrying multiples, go past your due date, or have high risk factors like high blood pressure or kidney or heart disease.
The profile will determine baby’s heart rate, activity level, breathing movements, muscle tone and the amount of amniotic fluid in the uterus. You already know what an ultrasound is. For the non-stress test, you’ll have sensors put on your belly to pick up baby’s fetal heart rate and your uterus’s contractions. Using the data from those two tests, your doctor can be sure baby is thriving. The tests will indicate the overall health of the baby, and if he appears to be in any danger, your doctor may decide to deliver him early.
Plus more from The Bump:
When Should I Have My First OB Appointment?
Most Common Pregnancy Symptoms
When to Break Up With Your OB
See More: 1st Trimester , 2nd Trimester , 3rd Trimester , Prenatal Tests , Prenatal Checkups
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