Comprehensive Chromosomal Screening: What Every IVF Nurse Should Know
Over 20 years have passed and, while earlier PGD tests were problematic, marked improvements have been made in the methodology, with better outcomes. Currently, the most popular technique is CCS, which tests all 23 pairs of chromosomes. In fact, the name PGD is often replaced with comprehensive chromosomal screening (CCS). With the availability of preimplantation screening, many patients prefer embryo screening over amniocentesis or intrapartum screening, avoiding the possibility of a difficult decision or a second trimester termination in the event of an abnormality.
Testing early-stage embryos helps IVF patients avoid potential heartbreak
Maryellen Matthews, RNC has been a Lead Nurse Coordinator at RMANJ since opening it’s doors in 1999. She works closely with her patients, helping to coordinate diagnostic testing as well as implementation of their treatment plans. Counseling patients about treatments and procedures, reviewing diagnostic testing, medication teaching and instruction and most importantly, offering emotional support to couples as they pursue their care, are just a few of Maryellen’s many roles as an IVF Nurse. Maryellen was recently interviewed by Carol B. Lesser, RNC, NP for Best Practices in IVF Nursing: Newsletter Series.
Do all of your nurses work with the Comprehensive Chromosome Screening (CCS) program or is this centralized in certain practices?
Maryellen: CCS is a widely utilized diagnostic tool at RMANJ. All of our nurses are educated about CCS and are able to counsel patients about this technique.
In determining the day of transfer, how do you decide? For example, if you have a morula-stage embryo on day 5, do you wait until day 6 for the biopsy? If you biopsy on day 6, would you absolutely freeze on day 6 to avoid the problem of dyssynchrony?
Maryellen: It is important for the embryo and the uterine lining to be in synchrony at the time of embryo transfer. Since embryos grow at their own pace, not all are blastocyst stage on day 5. Morulas are left in culture until day 6. If they become blastocysts at that time, they are biopsied. Although potentially viable, these embryos missed the important window of implantation and needed to be cryopreserved to avoid dyssynchrony.
Do you allow any patient to proceed with CCS, even low responders with single blastocyst?
Maryellen: All patients are eligible for CCS at our center. Low responders are a group that will likely benefit most from this diagnostic testing. CCS offers important decision-making information about the developmental competence of the embryo. If the embryo is chromosomally abnormal, we can prevent the disappointment of a failed transfer, the emotional upset of an embryo that implants and miscarries, or an embryo that implants and has significant abnormalities.
Have you found that CCS increases patient acceptance of single embryo transfer (SET)? What percentage of your cycles are SET?
Maryellen: The ultimate goal is a healthy pregnancy with the ideal obstetrical outcome: a singleton pregnancy. The transfer of a single embryo virtually eliminates the risks of multiple gestation. CCS is a tool that allows patients to elect SET without compromising pregnancy rates. A trial conducted at our center showed that the pregnancy rate for SET of a chromosomally normal embryo is equivalent to that rate when 2 unscreened embryos are transferred, with significant reduction in twin risk. With CCS, there is definitely greater willingness on the part of the patient to choose a SET and currently, a little over half do so.
Do you offer CCS to all age patients or do you focus on “older” patients?
Maryellen: As mentioned earlier, RMANJ offers CCS to all patients. The older patient, more at risk for aneuploidy, may often elect this procedure. However, younger patients with unexplained infertility, those with recurrent pregnancy loss, or couples looking to maximize their chances for successful pregnancy will also consider CCS.
Have you seen that patients who repeatedly produce aneuploidy embryos are better able to move on to donor eggs or adoption once they acquire this information?
Maryellen: The decision to move to donor eggs or adoption can be a long and difficult process for patients. They need to feel as though they have done everything they could to use their own eggs. Before CCS, IVF patients’ information about their chances for healthy babies was based on morphology of the embryos. CCS gives them some important decision-making information. If many or all of a patient’s embryos are genetically abnormal, she then has tangible information to aid in considering other options. Many of our patients have used CCS as a decision-making bridge to donor egg or adoption.
What has been your experience helping patients with recurrent pregnancy loss?
Maryellen: Many patients come to us with a history of pregnancy loss. These patients experience an additional level of sadness and frustration. It is believed that many of these pregnancies are lost due to chromosomal abnormalities. CCS is a common option chosen by this group of patients. After ruling out uterine or autoimmune issues as the cause for recurrent loss, CCS offers these patients the opportunity to select chromosomally normal embryos for transfer, thereby increasing their chances for successful outcomes. If all embryos are identified as aneuploid, this information helps some individuals and couples move to other ways of having a family.