SOOOOO I had to write a paper for my English 112 class.. and decided to do it on prenatal testing.. I figured I'd share the information so you ladies don't have to go search everywhere. Keep in mind it had to be 7 pages at 12 font... so it's long... I have included all my sources though so know that it's legit
Prenatal Tests: What is Best for My Baby?
Pregnancy is no easy task for a women?s body nor is it an easy task for her mind. With all our new technologies and new information acquired through research, a newly pregnant woman can be bogged down and confused trying to figure out which tests to take during her pregnancy. There are many tests that are done routinely and without question and others that most doctors will provide the patient with information and she must opt in or out.
The typical tests done during a pregnancy include a blood test, Pap smear, urine tests, an ultrasound mid-pregnancy, a glucose tolerance test, and a Group B Strep test. In the first trimester, at around 8 weeks, a blood sample will be taken. In this sample they test a few different things: Blood type and Rhesus factor (Rh), levels of human chorionic gonadotropin (hCG), hemoglobin levels, immunity to German measles (Rubella), hepatitis B, and also sexually transmitted diseases (STDs) are all checked. Women are recommended to have a Pap smear yearly and it is important to have one done during pregnancy. During the Pap the doctor swabs the cervix and checks for abnormalities. If the test comes back abnormal, further tests must be done to determine if the woman has cervical cancer, Human Papilloma Virus or something else. Bridget Bethea et al. found that ?Invasive cervical cancer is the most frequently diagnosed cancer in pregnancy? and that pregnancy is an opportune time for women to learn about cervical cancer, be tested, and seek medical attention if needed. Urine tests are done at each appointment. These are to examine the glucose levels, protein levels, ketones, and bacteria. The mid-pregnancy ultrasound is to determine if there seems to be any congenital defects in the baby and make sure baby is growing accordingly. The sonogram also allows the doctor to measure amniotic fluid, location of placenta, and check the fetal heart rate. Many women choose to find out the gender of their baby at this time. A glucose tolerance test is done between 24-28 weeks based of the last mistral period. A sugary drink (glucose) is ingested and a blood draw is done one hour later. If the women tests positive, meaning the body has high levels of glucose still and is not processing the sugar well, she must do the three-hour glucose tolerance test. If this second test comes back positive she is diagnosed with gestational diabetes. According to the American Pregnancy Association, ?Approximately 2-5% of all expecting mothers will develop gestational diabetes.? The last routine test taken is the Group B Streptococcus (Group B Strep/ GBS). It is done at 35-37 weeks. If the mother is positive, she must be treated with drip-antibiotics during labor so that the infection is not passed on to the newborn, as it can be fatal for the infant.
The routine tests are not typically offered as optional but throughout the pregnancy, the mother is offered other tests that are. These tests are optional for different reasons but usually fall in the categories of unlikely problems or a higher risk of complications occurring because of them. Some people will be strongly urged by their obstetricians to take tests based on their ethnicity, age, background, genetics, or previous problems. Fetal health, genetic abnormalities, Down syndrome and other birth defects are all found through optional blood tests, non-stress tests, nuchal translucency screening, Chorionic Villus Sampling (CVS), amniocentesis, cordocentesis, and the Quad Screen Test. In Steven Gabbe?s book Obstetrics: Normal and Problem Pregnancies, we find the risk of a newborn having Down syndrome or any chromosomal abnormality increases with the mother?s age (194) so being more aware of these tests when pregnant at an older age especially over the age of 35, is important. These tests are done to either prepare for a special-needs child, to terminate the pregnancy, or make sure that the baby is progressing correctly.
In the first trimester there are a few tests that can be done to test for abnormalities. The ?First Trimester Screen? is performed somewhere between week 11 and week 13. It includes a nuchal translucency screening (NTS) and a blood test. The NTS is a special ultrasound that measure the neck size while the blood test checks the hCG levels and pregnancy-associated plasma protein A (PAPP-A). If the levels of either hormone are too low or too high there might be a cause for concern. The scan, hormone levels and age are all combined to determine the risk factor. This test is not used to diagnose any chromosomal abnormality, just the chances for one. This test is harmless to the infant and only causes discomfort to the mother.
A second test that can be done in the first trimester is the Chorionic Villus Sampling (CVS). This test is done between 10-13 weeks of pregnancy. According to the Centers for Disease Control and Prevention, miscarriage has occurred 1 in every 100 after a CVS and there is a ?possible association between CVS and birth defects in infant [limbs].? Other problems that have occurred during the sampling are: ?Failure to obtain an adequate sample . . . Need for reinsertion of the instrument . . . Pain . . . Difficult insertion of the instrument . . . Poor visualization of the instrument . . . Vaginal bleeding follow procedure . . . ? (Young, Dadelszen, and Alfirevic 3). This test can be done two different ways: fluid can be extracted from the amniotic sac by inserting a needle into the belly or a tube through the cervix can extract it. If the risk factor for chromosomal abnormalities is increase, an obstetrician may recommend this test.
An amniocentesis is extremely similar to the CVS but must occur later in the pregnancy and fluid is only extracted through the stomach. An amniocentesis is performed between 15 and 18 weeks. Glyn Elwyn et al. state that it ?can be associated with a risk of foetal trauma, rupture, of membranes, foetal cutaneous lesions, maternal infections, and the loss of pregnancy. (126). During the procedure an ultrasound is performed to locate the infant?s position and a long, skinny needle is inserted into the belly. The National Institutes of Health reports that approximately four teaspoons of amniotic fluid are extracted and it takes about two weeks for results to come. The NIH also states that anencephaly, Down syndrome, rare, metabolic disorders, spina bifida, other neural tube defects, Rh incompatibility, baby?s lung development, and an infection of the baby may be diagnosed through an amniocentesis. Through personal experience, the procedure is not very painful but more so uncomfortable. There are some concerns that the test caused the stillbirth of my son sooner rather than later. Both the CVS and amniocentesis have false positives. According to the American Pregnancy Association CVS has 98-99% accuracy with a 1% chance of false positive while A. Daniilidis et al. state that the false positive for an amniocentesis is 5%. The amniocentesis is typically offered to all women around gestation age 16 weeks. Doctors do not usually recommend women at low-risk to do the amniocentesis but she is still able to opt in if she would like.
A third test that is similar to the CVS and amniocentesis is the cordocentesis or Percutaneous Umbilical Cord Blood Sampling (PUBS). It is usually done at 17 weeks gestation and when the amniocentesis is inconclusive. However, this test cannot detect neural tube defects. There is a higher risk of miscarriage with PUBS of 1-2 percent (American Pregnancy Association). Instead of taking fluid from the amniotic sac, blood is extracted from the umbilical cord. Results are usually available within 72 hours. Other concerns with doing PUBS are blood loss from where the sample was taken, infection, fetal heart rate drop, or a premature ?water-break.? CVS, amniocentesis, and PUBS are invasive procedures and all carry risks. It is extremely important to discuss with a doctor if the benefits outweigh the risks.
Another method of detecting chromosomal abnormalities is the Quadruple Screen Test done in the early- to mid- second trimester. The National Institute of Health reports that the test is most accurate when done between 16 weeks and 18 weeks. This test is just a simple blood draw and tests for four different things: Alpha-fetoprotein (AFP), human chorionic gonadotropin (hCG), unconjugated estriol (uE3), and inhibin A. AFP a protein produced by the infant?s liver and crosses through the skin of the infant into the amniotic fluid which then ?crosses into the mother?s blood? (Children?s Hospital of Pittsburgh). If hCG levels continue to be high during the second trimester of pregnancy, there is a higher concern for Down syndrome. ?Unconjugated estriol (uE3) is a form of estrogen that is produced by the fetus through metabolism . . . In pregnancies where the fetus has Down syndrome of Edwards syndrome, uE3 tends to be low? (Lab Tests Online). The placenta creates inhibin A. There are two parts and it is also known as dimeric inhibin A (DIA). This is another case where if the levels are high during the test period, there is concern for Down syndrome. ?According to ACOG, the triple screen detects Down syndrome in 69% of the cases while the quad screen detects it in 81% of the cases? (Lab Tests Online). The quad screen does not determine if a baby has an abnormality, it just determines if there is an increased risk.
During the last trimester of pregnancy, some obstetrician?s perform or offer a biophysical profile. The biophysical profile particularly performed when multiples are being carried, the mother is past the estimated due date, or for other high-risk pregnancies. A biophysical profile includes an ultrasound and a non-stress test. During the non-stress test a belt is wrapped around the mother?s abdomen and measures the baby?s heart rate. A second belt is used to measure contractions. Typically the heart rate and contractions are recorded for about half and hour. The non-stress test is not typically used until 28 weeks gestation. The test is non-invasive and causes no stress to the baby. The sonogram checks the same things as when the mid-pregnancy ultrasound was done. If there seems to be complications, the doctor may find it better to induce labor.
Many women crave the chance to look at their baby before it?s birth more than once. There is a routine ultrasound at around 20 weeks but often women don?t feel this is enough. Each obstetrician office has his/her own amount of routine ultrasounds and sometimes this includes more than one. If a woman doesn?t know a possible date of conception (typically based off of last menstrual period) an early ultrasound is sometimes performed to measure the embryo?s size. More ultrasounds are performed if the pregnancy is deemed ?high risk.? A pregnancy is high risk when the mother is over the age of 35, there is a genetic disorder or high chance of genetic disorder, there have been previous pregnancy complications, there are multiple babies, the women has experienced multiple pregnancy losses, and more. However, with ultrasounds comes risk as well. During a sonogram, the baby experiences a temperature increase as well as ?cavitation, acoustic streaming, radiation forces, and free-radical generation? (Houston and Newman 37). A benefit of the ultrasound is that it is non-invasive and the benefits outweigh the risks in practically all cases. There isn?t very much recent research done on the effects of ultrasound. They are much more common now than before the 1990?s where there are some questionable side effects (Houston and Newman 37). With limited knowledge, it is important to limit the amount that sonograms are used so that there aren?t potential negative effects.
With pregnancy comes many changes both physically and emotionally, causes for concern, an excess of new information, rules and regulations, and choices. Knowing which tests are routine and which tests are performed optionally is a big challenge. Many tests have risks and benefits and an expecting mother must decided which ones are necessary in her specific case. An initial blood sample is taken to check blood type, Rh factor, hCG, and hemoglobin levels as well as immunity to Rubella, hepatitis B, and STDs. A Pap smear is performed to check for cervical cancer and other infections, Urine is check quite frequently to view glucose and protein levels, ketones and bacteria. An ultrasound is performed to check for deformities. A glucose tolerance is done to check for gestational diabetes and a Group B Strep test is to check if the mother has an infection that can be fatal to the newborn. Blood tests such as the first trimester screen and quad screen test are non-invasive and cause only slight discomfort to the mother. These tests can be performed easily but only measure risk and do not diagnose. A chorionic villus sampling, amniocentesis, and cordocentesis should not be performed unless the risk of a genetic abnormality is deemed as high. Even with a high risk of chromosomal defects, these tests should be well thought through due to the risks of miscarriage and other problems associated with them. Many people choose to perform these tests to terminate their pregnancy. Others use them for comfort or for time to prepare for a special needs child. The biophysical profile is another non-invasive test and is good to see how the baby is doing and if there is a need to induce labor early. All testing is important to know about during a pregnancy.
American Pregnancy Association. ?Chorionic Villus Sampling: CVS.? American Pregnancy Association, Oct. 2008. Web. 15 May 2013.
American Pregnancy Association. ?Cordocentesis: Percutaneous Umbilical Cord Blood Sampling (PUBS).? American Pregnancy Association, Oct. 2008. Web. 15 May 2013.
American Pregnancy Association. ?Gestational Diabetes.? American Pregnancy Association, Oct. 2008. Web. 15 May 2013.
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Children?s Hospital of Pittsburgh. ?Alpha-fetoprotein (AFP).? UPMC, n.d.. Web. 15 May 2013.
Daniilidis, A. et al. ?A four - year retrospective study of amniocentesis: one centre experience.? Hippokratia. U.S. National Library of Medicine, National Institute of Health 2008. Web. 15 May 2013.
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National Institute of Health. ?Quadruple Screen Test.? MedlinePlus. U.S. National Library of Medicine, National Institute of Health, 7 August 2012. Web. 15 May 2013.
Olney, Richard et al. ?Chorionic Villus Sampling and Amniocentesis: Recommendations for Prenatal Counseling.? CDC. Center for Disease Control and Prevention, 21 July 1995. Web. 15 May 2013.
Young, Carmen, von Dadelszen, Peter, and Zarko Alfirevic. ?Instruments for chorionic villus sampling for prenatal diagnosis (Review).? Cochrane Database of Sytematic Reviews 2013, Issue 1, Art. No.: CD000114. DOI: 10.102/14651858.CD0000114.pub2. John Wiley & Sons, Ltd, 22 Nov. 2012. Web. 15 May 2013.