The PGS lab selection process prevents unexplained repeat miscarriages that are heartbreaking for couples
Habitual early fetal loss or miscarriage is a common fertility problem. It concerns young couples who have experienced at least three early miscarriages. They are the so-called biochemical pregnancies or miscarriages occurring before nine weeks of gestation.
These couples should not be categorized as infertile, for they have no difficulty conceiving. Such events are usually followed by a maternal depression due to an understandable frustration that worsens after each unfortunate episode.
A thorough work-up may help to detect the classical causes, such as immune reactions, chronic infections, uterine anatomy anomaly, inadequate hormone production or abnormal chromosomes in one of the parents. But in a majority of cases the miscarriage remains unexplained.
Recent progress in technology has provided an answer to this quandary. Preimplantation genetic screening (PGS) is done from a sampling of a few cells from the embryo. Amazingly, this is enough to have the chromosomal pattern checked by a specialized laboratory. The results have generally been surprising and most interesting. Couples with unexplained infertility or unexplained miscarriage had a very high ratio of cells with abnormal chromosomal distribution that made the embryos “incompatible with life or sustained pregnancy.”
For example, last year a young couple (husband and wife in their mid-twenties) that had experienced five early miscarriages came to our clinic. All tests were normal, ruling out all classical causes for repeat miscarriages. We advised them to go through in vitro fertilization (IVF) and PGS.
The biopsy results on eight well-formed, day-5 embryos were striking. Seven of them were affected with severe abnormalities (aneuploidy, which is the occurrence of one or more extra or missing chromosomes). Two of the embryos were missing one chromosome. Five others had one extra chromosome and/or an abnormal combination. Fortunately, one embryo was normal. It was transferred into the mother who finally had an uneventful pregnancy and delivered a normal baby.
We have observed five similar cases in our practice that we have counseled and treated in the same fashion. Four of them also had a happy outcome and one did not. The fifth patient had six out of six abnormal embryos. Several of our colleagues who also work in assisted reproduction have shared with us that they had comparable experiences.
So far, the three major indications for IVF are: diseased fallopian tubes, sperm with low quantity or poor quality and unexplained infertility. In view of our new experience, we can definitely add unexplained miscarriage to that list. IVF and PGS will provide the answer and in most cases will help the couple reach a happy outcome.