Prenatal Testing

Child is a gift from God. Every parent hopes for a healthy child. However, abnormalities in the fetus growth becoming common nowadays. These may be due to physical, radiation and chemical factors. These factors will cause deformities such as genetic mutation which causes mental retardation, abnormal body buildup and other conditions which bring a lot of troubles in the future to the child themselves and their parents. Modern technologies and innovations in the medical field had developed a method to detect the abnormality before delivery and prevent this future tragedy to happen. This method is known as prenatal screening. There are several advantages and disadvantages of prenatal screening.

Embryonic tissue that was removed is first tested for genetic abnormalities. This is done so that the healthiest embryos are frozen and implanted. Dr. Timothy Yeko, a medical director of the assisted reproductive technology program at the Reproductive Medicine Group in Tampa, talked about the genetic testing, “ Most of our patients now choose to have this genetic testing, which has come into widespread use in the past year or so. By doing this , the miscarriage rate has dropped by 50 percent because the genetically abnormal embryos are the ones that end in miscarriage.”

Prenatal testing includes screening and diagnostic testing that can provide valuable information to parents about the baby’s health. “Women are routinely offered a variety of genetic screening tests during their first three months of pregnancy to evaluate the risk for genetic disorders in their unborn baby” (livescience.com). I believe prenatal testing and counseling should not be mandatory and that each person needs to make their own decision based on their specific circumstances. Many prenatal tests are noninvasive and only require blood or urine and can test for HIV, anemia, diabetes, hepatitis B and preeclampsia. An ultrasound can also be used to detect some abnormalities with the baby. Doctors may strongly recommend that women who

Procedures such as amniocentesis and chorionic villus sampling (CVS) represent the standard diagnostic methods used by clinicians to screen fetuses for abnormalities or genetic disease such as Down syndrome. In amniocentesis, a needle is inserted into the amniotic sac of the mother and a small sample of amniotic fluid is obtained. Fetal tissue is contained within the amniotic fluid and is subsequently analyzed genetically and cytogenetically for abnormalities. In the case of CVS, a sample of placental tissue is obtained through the mother’s cervix for downstream genetic analysis as in the case of amniocentesis (CDC,

Therapeutic genetic manipulation is preformed by doctors to prevent diseases that the baby is carrying. The baby is tested by screening the embryo for any possible unknown diseases. Sometimes the PGD or preimplantation genetic diagnosis technique is used for this ("Biotechnology special focus"). The main diseases PGD is used to test for in babies are Hunntington's disease, Tay-sacks, Alzheimers, Familia cancers, Sickle Cell disease, Hemophilia, Neurofibromatosis, Fanconi's Anemia, Cystic fibrosis and most recently, Down's Syndrome ("Hooray for designer babies", 2002). This technique involves removing the unfertilized egg from the female, mating it with a sperm and then testing it for diseases. If all the diseases are absent, the fertilized egg is planted into the mother's uterus to develop into a baby. Some other unpredictable diseases may also be carried in the baby's chromosomes. Chromosome carrying diseases and disorders include: miscarriage of the baby, physical birth defects or down syndrome (Biotechnology special focus").

The first way that prenatal testing can be done is through something called a prenatal diagnostic test. "In general, it is the diagnostic procedures, such as amniocentesis and chorionic villus sampling, that people think of when they hear the term prenatal testing," (Press 1). Amniocentesis is when doctors take a sample of the fluid that surrounds the baby in the uterus to determine certain genetic disorders or chromosomal abnormalities. Chorionic villus sampling is when doctors take cells from projections on the placenta to also discover any genetic disorders or chromosomal abnormalities. These processes are considered "invasive" because they are putting objects that could potentially hurt the baby into the protective area surrounding the baby. These ways of prenatal testing come with a very negative feeling because they could possibly injure the baby, and the word invasive is attached to a very negative connotation. However, these options can find more abnormalities and diseases than non-invasive prenatal testing. "NIPT accurately diagnoses Down's syndrome, Edward's syndrome, Patau syndrome, Turner's syndrome, and numerical chromosome aberration and cannot detect other chromosomal anomalies," (Ryu & Kim 1). Even though this is true, NIPT is still a very beneficial option to the mother and unborn child. NIPT usually uses a DNA sample to determine chromosomal abnormalities that could lead to things such as Down's syndrome. The procedure is done by the doctors taking a sample of the mother's blood to determine what types of diseases and disabilities the baby will have. Many people like this type of prenatal testing because it is not detrimental to the baby, or mother's health. "Studies investigating the acceptability of NIPT suggest that pregnant women find it preferable because the standard screening is associated with more uncertain results and

The research design was appropriate and the results were reproducible between different studies. The validity indicated that direct comparison between each test was difficult because they had different cut-points to define pregnancies as high or low risk for Down’s syndrome. If all of the studies had the same cut-point, it would have made a direct comparison easier (Alldred, et al., 2013). There were different laboratories used to run different assays on different machines and methods. This may influence raw results and subsequent risk calculations (Alldred, et al., 2013). Very few papers made direct comparisons between tests, this was difficult to detect real differences that may exist between tests (Alldred, et al., 2013). This publication is current as of December 17, 2013.The article was able to answer my PICO question and met the stated requirements. The source included specific details about the sensitivity and specificity of the lab test. The author, S. Kate Alldred, she is affiliated with the Department of Women’s and Children’s Health at the University of Liverpool School of Medicine, in Liverpool, UK. She has authored other publications including “Frist and second trimester serum tests with and without first trimester ultrasound tests for Down’s syndrome screening”, “Second trimester serum tests of Down’s Syndrome screening”, and “Urine tests for

Technology on Prenatal screening might has helped to determine the health of the fetus before it's born but it has caused the legal and bioethical issues. It should be looked upon how fast the technology is advancing because without it there would be less abortion since no one would be seeking medical diagnosis.

pregnancies with abnormalities.“This is a test done during pregnancy to get information about the fetus

If the patient decides to continue with the pregnancy, there are many screening steps required for acceptable management of the disease. Ultrasonography of the fetus should be used throughout gestation, with a focus on the ocular structures. Neonatal magnetic resonance imaging has also been developed at some centers, which may allow to be more sensitive in detecting smaller calcifications. However, the method of magnetic resonance imagining in the fetus has not been studied enough in the context of a cancer risk fetus in regards to fetus safety. Some experts suggest that there should be early induction of the newborn, if they have been identified as “harboring high-risk features” on screening tests. However, this approach is not accepted with all experts in the USA. Therefore, this decision should be made on a case by case basis between all expert physicians involved in their respective fields (Gombos, 2012).

The genetic disorders like trisomy resulting from “triploidy” or nondisjunction have become one of the major concern in recent time because every year there are about 30 % cases related with embryonic and fetal deaths associated with chromosomal anomaly are being recognized, therefore Cytogenetic approach plays a major in terms of measuring the risk assessment and detecting chromosomal abnormality in advance. The main purpose of performing prenatal diagnosis is to determine the health and condition of an unborn fetus, and clarifying the possibilities of having predisposed to congenital anomaly which accounts for 20 to 30% of perinatal

This test involves a part of the placenta being retrieved during the mother’s third month of pregnancy. This is a shorter test procedure than amniocentesis due to the fact that doctors do not have to wait two to four weeks for the sample to grow in a culture in the lab. Instead, it may only take a few hours to get the results back. This test can be done earlier in the pregnancy: in the first trimester after the ten week period. Although this a quicker and more efficient test, it has a higher risk of the mother having a miscarriage due to being able to test much earlier (Mayo Clinic, 2015, Pueschel et al.,

There are three ways that a mother can be tested during pregnancy to see if their child will have Down syndrome. One is amniocentesis, which is the removal and analysis of a small sample of fetal cells from the amniotic fluid. Amniocentesis can not be done until the 14-18th week of pregnancy and with this process there is a lower risk of miscarriage than with the other two processes. Another process is chorionic villus sampling (CVS), which is the extraction of a tiny amount of fetal tissue at 9 to 11 weeks of pregnancy. The tissue is then tested for the presence of extra material from chromosome 21. Chorionic villus sampling has a 1-2% chance of the mother having a miscarriage. The last process is percutaneous umbilical blood sampling (PUBS), which is the most accurate method used to confirm the results of CVS or amniocentesis. During PUBS the tissue is tested for the presence of extra material from chromosome 21. PUBS cannot be done until the 18-22nd week and it carries a high risk of the mother having a miscarriage.

It can also be used to test for Tay-Sachs Disease, Fragile-X Mental Retardation, Cystic Fibrosis, Down Syndrome and Spinal Muscular Atrophy. In the past couples who wanted to have childr en, and were carriers of inherited diseases, worried about the possibility of their children inheriting the disease. Parents will no longer have this worry. In 1989, an English couple became the first to use PGD [Grady,1995]. It was used because they were at risk of passing along a form of severe mental retardation. Because it only affected sons, PGD was used to ensure that the couple had a daughter.

The next technique routinely performed for prenatal diagnosis is amniocentesis. A long needle is inserted into the mother’s uterus to withdraw a sample of amniotic fluid containing cells shed by the fetus. The cells are cultured and analyzed for chromosome abnormalities. Despite the lengthy time in obtaining results because the cells need to be cultured, this method has become widely accepted as a safe and accurate way to determine genetic disorders.