In order to assure you of a healthy pregnancy, several tests may be required, recommended or offered during your pregnancy. Some of these are included in the global fee for your pregnancy, but many are extras for which additional fees are charged. Most are covered by insurance, but specific questions about what your insurance covers should be addressed to your insurance company.
Obstetrical Panel Bloodwork and other tests
These are blood tests and a urine culture that is obtained at your “nurse talk” visit—your first obstetrical visit during which our staff gathers information about your past medical history, current pregnancy and educates you on prenatal care.
CBC – We check your blood counts to rule out anemia and infection.
Blood Type and RH – we check your blood type to see if you are a candidate for RhoGAM.
RPR/Syphilis – We also check an RPR to see if you have syphilis.
Hepatitis B – we check your hepatitis B carrier status to see if the baby will need to be immunized against hepatitis B immediately after birth.
Rubella – we check your Rubella status to see if you are immune to German Measles. If you aren’t immune to Rubella (German Measles), we cannot immunize you during pregnancy (since the vaccine is a live virus that could potentially infect your unborn child), but would recommend avoidance of known infected individuals during the pregnancy. We will also immunize you against Rubella before you leave the hospital after delivery.
Hemoglobin Electrophoresis – If you or the father of the baby is African-American, Mediterranean or Southeast Asian, we will also check a hemoglobin electrophoresis to see if you are a carrier for sickle cell disease or similar inherited disorders of hemoglobin formation.
Urine Culture – will be checked to see if you have asymptomatic bacteriuria—a bladder infection without symptoms. During pregnancy, such an infection could worsen to pyelonephritis, a kidney infection that could be life-threatening during pregnancy.
Each of these tests are standard tests that are required in early pregnancy.
The American College of OB/GYN and the CDC also recommend that all pregnant patients be screened for HIV. Most children who are HIV positive were infected from their mothers during pregnancy and labor. Since there are medications that can reduce the vertical transmission of HIV from mother to baby, it is recommended that all pregnant mothers be screened regardless of risk factors. You will be asked to sign a consent either to draw the HIV test or to decline the test.
The Genprobe test is to detect both gonorrhea and chlamydia from the cervix of infected women. The State of North Carolina requires that all pregnant women be screened for both. The physician will perform this test at your New OB visit at the time of a vaginal speculum exam.
If you have not had a Pap test to screen for cervical cancer in the last year, you will also have this performed at your New OB visit with the physician at the same time that the Genprobe is performed.
Approximately 5% of pregnant women develop diabetes during pregnancy—gestational diabetes. Most of these women have no signs or symptoms of diabetes but are at higher risk of stillbirth and delivery of large babies. In order to detect these women and thereby treat their diabetes in order to lower their risk of adverse outcomes, we perform a glucola screen on all pregnant patients (if they aren’t already diagnosed with diabetes before pregnancy) at 26-28 weeks. If you were diagnosed as having gestational diabetes during a previous pregnancy, you are at higher risk of recurrent gestational diabetes during this pregnancy and we will screen you at 16 weeks also. Even if you “pass” the first glucola, we will screen you again at 26-28 weeks since the hormones of pregnancy that cause gestational diabetes are higher later in pregnancy.
If your blood type is Rh negative, we will check your blood for the development of antibodies against a potentially Rh positive baby at the time of your 28-week glucola screen. You will then receive a shot of RhoGAM to prevent sensitization during late pregnancy. After delivery, if your baby was indeed Rh positive, you will receive a second dose of
RhoGAM to prevent sensitization during the delivery and postpartum period. We rarely see Rh isoimmunization any longer since the development of RhoGAM. The other situation in which you may need antibody screening occurs when the antibody screen done at your initial obstetrical panel was positive for other potentially harmful antibodies. In this situation, you may need antibody screens as frequently as monthly.
First Trimester Screening
Chromosomal abnormalities occur when a child has an abnormal number or size of the chromosomes in his or her cells. The chromosomes carry the genes that control all cellular functions; therefore abnormalities in chromosomes result in severe abnormalities in babies—and many are lethal abnormalities. First trimester screening involves performing an ultrasound and doing bloodwork between 11-14 weeks of pregnancy. We use the ultrasound to measure the thickness of the nuchal translucency—a pocket of fluid that all babies have on the nape of the neck in early pregnancy. Fetuses with chromosomal abnormalities have thicker nuchal translucencies. The blood sample measures the amount of Pregnancy Associated Plasma Protein A (PAPP-A), the pregnancy hormone HCG and Dimeric Inhibin A. By combining the measurements obtained from the blood and ultrasound, we can detect 86% of Down’s Syndrome (Trisomy 21) and 75% of the babies with Trisomy 18 (another common chromosomal abnormality). The test will probably detect other types of chromosomal abnormalities also and can detect 40% of babies with heart defects. If this screening test indicates that you are at high risk for having a child with one of these chromosomal abnormalities, you will be offered a diagnostic test such as amniocentesis or CVS (chorionic villus sampling). In summary, First Trimester Screening will detect the majority, but not all, chromosomal abnormalities. If you wish to diagnose 100% of these abnormalities, you should consider amniocentesis or CVS (chorionic villus sampling). First trimester screening is indicated for women who do not have risk factors for having a child with chromosomal abnormalities (such as maternal age >34 or a prior child with chromosomal abnormality). If you are at high risk already, you may wish to undergo more definitive testing.
Second Trimester Double Screen Testing
Early in pregnancy the spine is a flat plate with the spinal cord running on top of it. At about 5-6 weeks of pregnancy, the flat plate rolls up and envelopes the spinal cord much like conduit surrounds electric wires. In very rare instances (about 1 in 500 pregnancies), the closure is not complete, allowing the spinal cord to protrude and be damaged. Children that are born with this condition—meningomyelocele or spina bifida—have difficulty with bowel and bladder control and are confined to wheel chairs due to damage to the nerves that innervate these areas. A positive family history or the presence of other risk factors for having a child with an open neural tube defect (ONTD) may increase the risk above the 1 in 500 level. We have a blood test that can screen for this defect. We obtain a sample of blood between 14-16 weeks from which the level of AFP (alpha fetoprotein, a major blood protein produced by the fetus) along with estriol (an estrogen), pregnancy hormone (HCG) and Dimeric Inhibin A are measured. The tetra screen calculates your risk for having a child with either an ONTD, Down’s Syndrome (Trisomy 21) or Trisomy 18. An excellent screening test for ONTDs (detects 80%), it is not as sensitive as First Trimester Screening for detection of either Down’s Syndrome (75%- 80% detection) or Trisomy 18 (73% detection). The false positive rate for both the tetra screen and First Trimester Screening is equal at 5%. If the tetra screen indicates increased risk for a chromosomal abnormality, you will be offered a targeted ultrasound to look for soft anatomic findings in the fetus that may indicate increased risk for a chromosomal abnormality and you will be offered amniocentesis. If you want 100% assuredness, you may wish to proceed with amniocentesis first.
When you come to our office for your initial obstetrical visit, you will meet with our obstetrical staff, who will record your past medical and obstetrical history and discuss the routine do’s and don’ts of pregnancy as well as what to expect during your pregnancy. We call this the “Nurse Talk” visit. If appropriate, you will also do an ultrasound with our ultrasonographer in order to confirm your due date and make sure the pregnancy is progressing well. We would also detect twins at that ultrasound. Later in pregnancy, between 18-20 weeks, we routinely ultrasound all patients to assess fetal anatomy. During your pregnancy, you may need other ultrasounds for confirmation of fetal position, growth or well-being. Check with your insurance company to see how they cover ultrasounds during pregnancy. If you want an ultrasound for maternal concern, but there are no medical indications for an ultrasound, we will be happy to schedule one, but your insurance company will not pay and you would then be responsible for the fee.
If you are at risk for having a child with a chromosomal abnormality, you may also be offered a targeted ultrasound with one of the maternal-fetal specialists from UNC or Duke. These ultrasounds look for “soft” anatomic differences in fetuses with chromosomal abnormalities such as shortened femurse (thigh bones), thickened fat pads on the neck and bright
ultrasound echoes in the heart or bowel. If all these areas are normal, there is a 60% chance the baby doesn’t have a chromosomal abnormality.
We offer in-office amniocentesis for our patients who need and desire this service between 15-20 weeks of pregnancy. The procedure involves doing an ultrasound to assess the fetus and locate a pocket of amniotic fluid around the fetus that is accessible. Your abdomen is then prepped with an antiseptic solution and anesthetized with a “bee-sting” of local anesthesia. A sterile sheath is then placed over the ultrasound transducer and the transducer placed onto your abdomen in a sterile fashion so that we can watch the tip of the slender needle that is then inserted into the pocket of fluid. After withdrawing approximately one ounce of amniotic fluid under ultrasound observation, the needle is removed and you are allowed to see the baby again. The generally quoted risk of amniocentesis causing a miscarriage is 0.5%. With ultrasound guidance, the risk is probably lower at 0.3%. Following the procedure, you should avoid heavy lifting or strenuous activities for 48-72 hours. Amniocentesis can detect chromosomal abnormalities, open neural tube defects and other suspected genetic abnormalities.
Chorionic Villus Sampling (CVS)
CVS is performed between 10-12 weeks of pregnancy. The procedure involves inserting a small cannula (like a straw) under ultrasound guidance through the cervix and into the placenta. Alternatively a needle may be inserted through your abdomen into the placenta. A small amount of placental tissue is removed and sent to the lab for analysis. Since the laboratory must be immediately available, we refer our patients who need to undergo CVS to the Maternal Fetal Medicine specialists from UNC or Duke that are here in Raleigh. CVS can detect chromosomal abnormalities and suspected genetic abnormalities but cannot detect open neural tube defects. The procedure is performed at an earlier gestational age than amniocentesis, but carries a higher risk of miscarriage (1%).
NonStress Testing (NST)
Sometimes the doctors will want to assess the baby’s wellbeing by doing a nonstress test. This test involves placing a fetal monitor on your abdomen to continuously measure the fetal heart rate. When the baby moves, we expect to see an acceleration in the fetal heart rate for a period of time following the movement after which time the heart rate returns to its baseline rate. If we do not get adequate accelerations, we may stimulate the baby through your abdomen with a sound-producing device (much like an alarm clock buzzer).
Biophysical Profile Testing
Another way of assessing fetal wellbeing is to do an ultrasound called a biophysical profile or BPP. Using the ultrasound machine, the sonographer measures the amniotic fluid volume around the baby and watches to see if the baby “breathes” the fluid into his/her lungs. The sonographer will also assess the degree of tone of the baby and limb movements. Each of these four criteria are scored either 0 or 2 and totaled together. A perfect score is 8 and a 6 is passing.
Group B Strep Testing
Group B Strep (GBS) is a normal bacterium in the lower genital tract of 40% of females in the reproductive age group. It rarely causes infection in the nonpregnant patient but in 2-3 per 1000 pregnant women it will cause infection for either the mother or baby in the immediate postpartum period. Since GBS is a very serious infection for newborn babies, the standard of care is to treat all known or suspected GBS colonized women with IV antibiotics when they come to the hospital in labor to lower the risk for either newborn or maternal infection. Since it doesn’t help to treat uninfected but colonized women before labor starts, the standard of care is to wait to culture the vagina until 35-36 weeks of gestation (4-5 weeks before your due date). If you had a previous child with GBS infection immediately postpartum or if you had a urine culture that was positive for GBS, you probably carry higher levels of GBS in your genital tract and, therefore, doing the vaginal culture is not necessary. We will assume you will be GBS positive and treat you with antibiotics when active labor starts. If you had a positive vaginal culture during a previous pregnancy, you should still be cultured during your current pregnancy since your levels of GBS may have dropped for the current pregnancy. Even if your GBS culture is negative, we will treat with antibiotics in labor if you develop risks for GBS infection such as prolonged rupture of the amniotic sac, premature delivery or fever.
Cystic Fibrosis (CF) Screening
Cystic Fibrosis is an inherited disorder that results in varying degrees of respiratory and digestive problems in affected individuals. In order to have the disease, you have to have the affected gene from each of your parents (autosomal recessive inheritance). About 1 in 30 Caucasians are carriers (have one gene) for the disease. If two carriers have a child, the chance their child will have the disease is 1 in 4 (25%). Other ethnic groups are less likely to be carriers (i.e. Hispanic Americans 1 in 46, African Americans 1 in 65 and Asian Americans 1 in 90). If you have a positive family history of someone with CF, your chance of being a carrier may be higher. The American College of Obstetricians and
Gynecologists recommends that carrier testing be offered to all ethnic groups. The testing involves obtaining a blood sample from one or both parents. If the test is negative, it is highly unlikely that you are a carrier.
For more information, refer to www.acog.org