Of the known causes of recurrent pregnancy loss, chromosomal abnormalities account for the majority of miscarriages. Biopsying an embryo for preimplantation genetic testing has revolutionized the treatment of recurrent pregnancy loss, by improving the embryologist’s ability to choose the healthiest and most chromosomally normal embryo for transfer.
Miscarriages can be emotionally and physically challenging for both women and couples. Recurrent pregnancy loss, which is defined by the American Society of Reproductive Medicine as two or more failed clinical pregnancies, can be devastating. Estimates vary, but at least 5% of women will suffer more than one miscarriage, and it is important that their evaluation be thorough, and their treatment be precise.
Recommendations vary regarding the evaluation and treatment of women with recurrent pregnancy loss, and debate exists about which treatments are most effective. Evaluation of a woman with multiple miscarriages includes a search for structural, hormonal, infectious, immunological, and genetic causes. Frustratingly, in up to 50% of women with recurrent pregnancy loss, a clear cause will not be identified. Of the known causes, chromosomal abnormalities account for the majority of miscarriages.
When a woman has a fibroid or abnormally shaped uterus (such as a uterine septum), surgical correction is usually indicated. When a woman suffers from recurrent miscarriages due to chromosomally abnormal eggs and embryos, we usually recommend that she undergo in vitro fertilization (IVF) so that we can analyze her embryos prior to implantation. Preimplantation genetic testing of embryos has revolutionized the treatment of recurrent pregnancy loss. Biopsying and sequencing an embryo allows us to choose the best embryo for transfer and to minimize the likelihood of miscarriage. More than half of embryos are chromosomally abnormal, and the percentage of abnormal eggs increases each year with maternal age. This is significant because up to 90% of chromosomally abnormal pregnancies abort spontaneously, compared to only 7% of chromosomally normal pregnancies. As such, selection of the healthiest embryo is integral to improving outcome in patients at risk for miscarriage.
As women age, natural fertility declines, and it becomes more difficult to find a normal embryo. In some women, it may even take more than one egg retrieval to find a healthy embryo for transfer. The good news is that available literature has found IVF with preimplantation genetic testing of embryos to be a safe and effective way of helping patients conceive and deliver a healthy baby.
We are fortunate to live in an era in which technology can be used to help prevent human disease and suffering. Preimplantation genetic screening using next-generation testing of embryos allows for selection of the healthiest embryos for transfer. Data continues to accumulating that by using the right technology, healthy outcomes are common, even in patients who previously suffered from recurrent pregnancy loss.
Dr. Alan B. Copperman
Medical Director of the Division of Reproductive Endocrinology and Infertility, RMA of NY