Preimplantation genetic testing and placental abnormalities: a systematic review and meta-analysis

Preimplantation genetic testing (PGT) is being used with increasing frequency in in vitro fertilization (IVF) cycles, most commonly through trophectoderm biopsy at the blastocyst stage. While the benefits of optimizing pregnancy chances by selecting for known euploid embryos are largely established, the potential negative fetal or pregnancy related implications are less understood. Given that the chorion and placenta arise from trophectoderm, we hypothesized that biopsy of these cells may disrupt normal development. We therefore conducted a meta-analysis of published data to evaluate the risk of placenta-related disorders following embryo biopsy for PGT. Using PRISMA guidelines, we conducted a literature search of Medline (Ovid) on the risk of placenta accreta spectrum (PAS) and in vitro fertilization using MeSH headings (placenta accreta and in vitro fertilization) as well as equivalent keywords, phrases, and truncated terms. In addition to PAS, other placental abnormalities that were included were placental abruption, placenta previa and preterm premature rupture of membranes (PPROM). The search strategy was then translated from Medline to Embase and Web of Science. Citation titles and abstracts were screened by two investigators, and relevant studies were downloaded and reviewed in their entirety. Data was then extracted and verified by two investigators. The Newcastle Ottawa scale was used to assess study quality, Higgins I2 was used to assess heterogeneity, and the meta-analysis was conducted using RevMan 5.4 software using a Random Effects model. Searches were conducted on February 16, 2023, and we retrieved 282 unique citations. Seven studies reported original data on placental abnormalities following embryo biopsy for PGT and included a total of 1,783 PGT patients and 33,976 No-PGT patients. There were no statistically significant differences in patient age (MD 0.46, 95% CI -0.70 – 1.62), but BMI was significantly lower in PGT compared to No-PGT patients (MD -0.55, 95% CI -1.03 – -0.08). Rates of PAS between the PGT or No-PGT groups did not differ in our analysis (OR 0.78, 95% CI 0.22 – 2.76). Similarly, there were no differences in rates of PPROM (OR 1.17, 95% CI 0.84 – 1.62), placental abruption (OR 1.67, 95% CI 0.85 – 3.26), or placenta previa (OR 1.54, 95% CI 0.74 – 3.21). Lastly, there were no differences noted when aggregating all placental disorders together (OR 1.10, 95% CI 0.83 – 1.45). In this updated and expanded meta-analysis, we found no association between PGT testing and PAS or other placental abnormalities including PPROM, placenta previa, or placental abruption, consistent with previous findings. The association with higher BMI and No-PGT status was an unexpected finding and presents an opportunity to research whether implicit bias in counseling contributes to the difference in PGT completion.