Testing for genetic or chromosomal abnormalities can help couples realize their dream of having a child.
Couples undergoing in vitro fertilization (IVF) may decide to have the embryo tested for genetic or chromosomal abnormalities. Since a healthy embryo increases the chances of a successful pregnancy, couples who have suffered repeated miscarriages may find preimplantation genetic testing worthwhile.
A history of miscarriages isn’t the only reason a couple may consider preimplantation genetic testing, however. If several IVF cycles have failed to produce a pregnancy, genetic testing may be recommended. Couples known to carry certain genetic diseases may also benefit from preimplantation testing. Older patients or those with low egg quality would qualify as well. Finally, couples may want to pursue genetic testing to determine the gender of the baby.
There are two types of preimplantation genetic testing methods: preimplantation genetic diagnosis (PGD) and preimplantation genetic screening (PGS). Each test increases the likelihood of a successful pregnancy and a child free of genetic disorders.
Preimplantation Genetic Diagnosis
PGD analyzes the cells of the embryo for genetic disorders — such as cystic fibrosis, neurofibromatosis, sickle cell disease, and Tay-Sachs disease — that are passed on through the parents. More than 100 genetic conditions can be found through PGD.
To perform the test, cells from the embryo are removed five days after fertilization while the embryo is still developing. The DNA in those cells is then examined for the presence of any genes that could produce a hereditary disease. If the embryo is free of any genetic abnormalities, it will be implanted into the uterus. If there is more than one embryo developed and tested, those without a genetic disorder can be frozen.
Couples who decide to have PGD should be aware that it extends the IVF cycle. After egg retrieval and fertilization, the embryo grows for five days before testing can be performed. Getting the results could take up to two weeks.
Preimplantation Genetic Screening
Unlike PGD, PGS tests the embryo for chromosomal irregularities, such as too many or too few chromosomes instead of the standard 46. Down Syndrome, for example, is caused by a chromosomal anomaly.
PGS also uncovers any X-linked genetic diseases, such as Duchenne muscular dystrophy. X-linked genetic conditions are located on the X chromosome. Women have two X chromosomes, while men have one X and one Y.
PGS can help couples uncover why they have suffered multiple miscarriages. Chromosomal abnormalities may account for the vast majority of first-trimester miscarriages. Therefore, learning an embryo doesn’t harbor any chromosomal irregularities increases the odds of a successful implantation and pregnancy.
Learn More About PGD and PGS
Thinking about preimplantation genetic testing? The staff at New York Reproductive Wellness can guide you through the PGD and PGS process. In addition to those methods, we offer Next Generation Sequencing (NGS), which can accurately identify an unprecedented number of chromosomal anomalies.
Our team of embryologists specializes in diagnosing genetic and chromosomal disorders in a developing embryo so parents can make an informed decision. If you’d like to learn more, please contact our office for a consultation.