I’ve participated in some rather interesting discussions recently of what prospective parents (especially those using assisted reproductive services such as IVF or donor egg IVF) might want to consider for genetic screening prior to conceiving. It turns out, there really aren’t any hard rules or “must use” checklists.
For the sake of this conversation, we’ll just talk about the tests done prior to any fertility treatments or conception. They are performed on the potential parents (or egg & sperm donors if you are using those) to screen out or minimize the risk for genetic disorders that may be passed down through DNA. In a future post, I’ll talk about PGD (pre-implantation genetic diagnosis) or CGH (comparative genome hybridization), which are big words for two types of genetic screening that are available after the embryos are formed through IVF, but before they are transferred back to the mother or gestational carrier/surrogate.
Depending on which geneticist, OB, or RE you ask about pre-conception genetic testing, you will likely get a different response. And if you are doing IVF or other assisted fertility treatment with your own eggs, unless you already know about some inherited genetic disorders in your family that you wish to screen out, you might be less inclined to check every option than if you were selecting an egg donor and had the option of selecting a donor who you know had passed the screening for the potentially “bad stuff”.
Most clinics that specialize in egg donor treatments (and donor agencies) have been testing their egg donors for STDs along with genetic tests for Cystic Fibrosis and depending on ethnicity or heredity - sometimes Sickle Cell Anemia or Tay Sachs. Some clinics include karyotype testing, to identify and evaluate the size, shape, and number of chromosomes in a sample of body cells. Extra, missing, or abnormal positions of chromosome pieces can cause problems with a person’s growth, development, and body functions.
More recently, a few additional tests are popping up on the common testing list of some clinics. But even if they are not standard at your clinic, you can usually request them as long as you are willing to bear the expense of the testing. The two tests that are popping up more these days are:
- SMA – spinal muscular atrophy
- Fragile X
Perhaps the best advice aside from discussing this with your RE is to consult with a genetic counselor prior to making your decision. These tests can become even more important for the person providing the eggs if the genetic heredity of the sperm you are using (your partner or donor sperm) also has genetic weaknesses that may be passed on.
To date, many patients and doctors have not been so concerned with those last two tests unless the patient or donor has a genetic history, or if the patient happens to know someone with this diagnosis and can see the challenges that may come along with them. In some cases, you may elect not to do these additional tests, but instead do a CVS or amnio to test for them once the fetus is growing.
I think information and knowledge provide power. So, the most important thing is to ask questions so you understand exactly what tests are done routinely, and which ones may be recommended or only available if you ask for them. That way you can decide what is best for your family!