Dados do Trabalho

Title

MATERNAL AND NEONATAL OUTCOMES AFTER FROZEN EMBRYO TRANSFER WITH AND WITHOUT PGT

Objective

It is known that children born after frozen embryo transfer (FET) and in vitro fertilization have some differences in neonatal outcomes. However, there is no sufficient data in the literature comparing these parameters in pregnancies and births after FET with or without preimplantation genetic test (PGT) biopsy. Thus, the objective of this study was to analyze if there is any difference regarding obstetric and perinatal outcomes after FET with/without PGT.

Methods

Retrospective, observational, cross-sectional study. A total of 897 pregnancies were analyzed between 2016 and 2021. The sample was divided into two groups: G1 - did not perform PGT (n=629 pregnancies, 546 singletons, and 83 twins), and G2 - performed PGT (n=268 pregnancies, 247 singletons, and 21 twins). All embryos were submitted to hatching after thawing; therefore, the embryos submitted to PGT received two hatchings, according to the clinical protocol. The variables regarding maternal and neonatal outcomes were analyzed separately for single or twin pregnancies. Statistical analysis: Student's t-test, chi square, and Fisher's exact test, considering p<0.05.

Results

Data were compared between G1 vs. G2, respectively: twins rate after one embryo transfer (1.6% vs. 3.8%, p=0.064); and after two embryo transfers (25.4% vs. 35.3% p=0.157). Single pregnancy results (G1 vs. G2): gestational age (GA), wks (38.2 vs. 38.1, p=0.382); prematurity, %: (12.0 vs. 14.6, p=0.315); birthweight, g (3259.8±561.0 vs. 3209.0±587.9, p=0.245); small for GA,% (4.2 vs. 3.6, p=0.705); low birthweight, % (4.4 vs. 3.2, p=0.447); Apgar 5' >7,% (96.7 vs. 97.2, p=0.743); neonatal UCI admission,% (4.9 vs. 6.9, p=0.187); maternal hypertension, % (5.6 vs. 6.1, p=0.629); gestational diabetes, % (4.0 vs. 3.2, p=0.692). Twin results (G1 vs. G2): number of fetuses (166 vs. 42), GA, wks (35.1 vs. 36.1, p=0.101); prematurity, % (71.8% vs. 66.7%, p=0.647); weight, g (2321.8±554.4 vs. 2463.7±346.5, p=0.139); Apgar 5th >7, % (92.8 vs. 95.2, p=0.741); there were no differences in maternal and fetal complications or chromosomal anomalies.

Conclusion

There were no statistically significant differences considering maternal and perinatal outcomes regardless if the embryo was biopsied in frozen embryo transfers. The biopsy seems safe for the newborn and does not increase maternal complications. There is a tendency for a higher twinning rate when one biopsied embryo is transferred, and the twin pregnancy rate is extremely high when two embryos are transferred in both groups.

Keywords

Maternal outcomes; neonatal outcomes; PGT.