Freelance writer for Contemporary OB/GYN
Preimplantation genetic testing for aneuploidy (PGT-A) is not associated with a difference in risk of fetal anomaly detected on mid-trimester anatomical survey, according to a study.
The retrospective cohort study in the Journal of Assisted Reproduction and Genetics (JARG) calculated the rate of fetal anomalies detected on anatomy ultrasound in pregnant patients who underwent in vitro fertilization (IVF) with PGT-A, compared to patients who conceived following IVF with unscreened embryos and age-matched patients with natural conception.
“PGT-A has been increasingly used in IVF cycles in the United States, with reported use in over 40% of cycles in 2018,” said principal investigator Carrie Riestenberg, MD, a reproductive endocrinology and infertility specialist at Reproductive Partners Medical Groups in Redondo Beach, California. “However, while PGT-A is a valuable tool, its utility is frequently misunderstood by doctors and patients alike.”
A previous survey conducted at a high-volume academic IVF practice found that for the majority of patients, their primary reason for pursuing PGT-A was to increase the chance of having a “healthy baby,” and many other patients indicated it was to reduce the risk of birth defects.
“But the few studies that have investigated if PGT-A actually reduces the risk of birth defects have not had this conclusion,” Riestenberg told Contemporary OB/GYN. “Our goal was to add to the body of literature on PGT-A and the risk of congenital anomalies.”
The current study, which Riestenberg and colleagues conducted at her high-volume maternal-fetal medicine practice in Los Angeles, consisted of patients with singleton pregnancies who had a mid-trimester anatomy ultrasound between January 2017 and December 2018.
A total of 712 patients who conceived after IVF, with or without PGT-A, were age-matched with natural conception controls.
The percentage of sonographic major abnormalities were 3.8% for natural conception, 4.2% for IVF without PGT-A and 3.8% for IVF and PGT-A.
For minor abnormalities, the percentages were 10.1%, 11.9% and 12.2%, respectively.
Rate of abnormal nuchal translucency, high-risk noninvasive prenatal testing (NIPT) and abnormal invasive diagnostic testing were also similar between IVF and natural conception patients.
However, patients who conceived after IVF, with or without PGT-A, had significantly higher rates of abnormal placental ultrasound findings compared to natural conception controls: 8.8% for IVF with PGT-A and 8.9% for IVF without PGT-A vs. 2.9% for natural conception (P < 0.001).
Likewise, patients with natural conception had a significantly lower rate of abnormal second trimester serum analytes than the other two groups: 0.9% vs. 4.5% for IVF with PGT-A and 3.5% for IVF without PGT (P = 0.003).
“Our finding that the use of PGT-A was not associated with a difference in the rate of fetal anomalies detected on mid-trimester ultrasound was not surprising, given that two-thirds of congenital anomalies are of unknown etiology and would therefore not be expected to be detected by PGT-A,” Riestenberg said.
The results of the study highlight the importance of patient counseling as to the limitations of PGT-A and of providing standard prenatal care for pregnancies conceived through assisted reproductive technology (ART).
Riestenberg reports no relevant financial disclosures.
Riestenberg CK, Mok T, Ong JR, et al. Sonographic abnormalities in pregnancies conceived following IVF with and without preimplantation genetic testing for aneuploidy (PGT-A). J Assist Reprod Genet. Published online February 3, 2021. doi:10.1007/s10815-021-02069-5