For mothers-to-be, even the most textbook pregnancy is fraught with worry. When you add infertility into the mix, it becomes a real rollercoaster of emotions. Will my age cause a concern? Will the baby be ok? Will they experience any health issues? And on and on. The unknown can cause plenty of sleepless nights and stress just when you need more sleep and less stress in your life.
Genetic screening, before and during pregnancy will help you, and your partner alleviate some of the worry over the unknown. For those couples with known genetic conditions preconception screening with your physician helps to clear up concerns and inform you of the chances your child will be affected.
Types of Genetic Screening
Genetic screening in pregnancy, such as chorionic villus sampling (CVS) or amniocentesis detect genetic diseases, chromosomal abnormalities, birth defects and other conditions your fetus may have.
Couples going through IVF benefit from preimplantation screening as this helps determine the viability of the embryo and any conditions the embryo may carry prior to pregnancy. All of the genetic testing aids in the conception and birth of a healthy baby.
Preconception genetic screening is a way for couples to investigate their own genetic make-up prior to trying to conceive. Assessing and understanding the genetic markers you carry and could, potentially, pass on to your child helps you to understand the genetic risk. You and your partner could carry a gene that predisposes your offspring to genetic conditions, even though you yourselves don’t have any symptoms.
You and your physician will determine what genetic conditions to look for based on your ethnicity and background. Some conditions are more prevalent in certain ethnicities, such as Tay-Sachs in Ashkenazi (Eastern European) Jewish people and sickle cell anemia in those of African descent. Caucasians of European descent should be checked for cystic fibrosis.
Preconception genetic testing involves drawing blood and screening for genetic conditions based on your family history and knowledge. Genetic testing looks for gene mutations and provides you with the percentage of risk to your potential offspring.
Chorionic Villus Sampling (CVS) is a test given to women who are already pregnant. The test takes a small sample of cells from the placenta. Because the placenta is created from the fertilized egg, it will have the same cells as the baby.
CVS helps to identify conditions such as Down syndrome, cystic fibrosis, Tay-Sachs, Thalassemia and sickle cell. The CVS test is 98% effective when diagnosing chromosomal disorders. The test is also used to identify biological gender, which is important when testing for sex-specific conditions. CVS can’t be used to detect open neural tube defects such as spina bifida.
Those who have a history of certain chromosomal disorders, women over the age of 35, those who have a child or family member who has certain birth defects or those couples who’ve received abnormal results from a genetic screening that bears further investigation.
Amniocentesis tests the amniotic fluid surrounding the baby to assess development and look for certain birth defects. Your physician will use an ultrasound transducer to identify the position of the baby and the right point to insert the syringe. A thin, hollow needle is then inserted through your abdomen into the uterus and amniotic fluid is withdrawn.
After the fluid is tested your physician and, possibly, a genetic counselor will go over the results with you. Amniocentesis can identify certain-but not all-genetic abnormalities. This test is also used to assess fetal lung development, infections, certain Rh conditions, and paternity.
There are risks associated with amniocentesis including miscarriage, although the overall risk is very low. Discuss your need for this type of test with your physician.
Preimplantation Genetic Testing
Preimplantation genetic testing (PGT) is quite common in those couples and individuals going through IVF. PGT is used to examine embryos, before implantation into the uterus, to look for a range of genetic issues which can result in failure to implant, miscarriage and birth defects. PGT is extremely useful is assessing chromosomal abnormalities and genetic disorders which could complicate the success of IVF.
The test is performed on the fertilized egg at about 5 days post fertilization (blastocyst stage). The test examines cells destined to become the placenta, not the baby. The results usually take a few days. Then implantation is scheduled.
PGT can also be done on harvested eggs prior to fertilization. Neither fertilized nor unfertilized eggs that are tested go on to pose risks to the developing embryo or the future child.
Peace of Mind
For those couples and individuals who are planning to conceive, these tests can provide information that will give you peace of mind. If you are concerned about specific defects or conditions related to your genetics consult with your physician. Together you can determine the best testing and the best course to a healthy pregnancy.