36w6d and 2) birth weight (BW) and low birth weight (LBW) defined as <2500g. A secondary outcome was a composite complication rate defined by inclusion of any of the following: hypertensive (HTN) disorders of pregnancy, HELLP syndrome, intrauterine growth restriction, oligohydramnios, abnormal placentation or umbilical cord anomalies. Statistical analyses included a Kolmogorov-Smirnov, Mann-Whitney U, chi-squared, and logistic regression where appropriate, with p<0.05 considered significant.RESULTS: 647 cycles were included: 491 PRG and 156 NAT. Mean patient age was 37.2 AE 4.4 years (range 21-59). 7% (n¼45) were donor egg (DE) recipients but use of protocol was not different (8.2% PRG vs 3.3% NAT, p¼0.05). In this cohort, 7 (1.1%) had HTN, 3 (0.5%) had diabetes, and 81 (12.6%) had depression/anxiety. Mean gestational age (GA) at birth was 39 AE 1.9 wks (range 24w1d-42w4d), and 7.9% had PTB. Mean BW was 3299.4 AE 567.3 grams (range 737.1-5017.9). Infants with LBW and macrosomia ( 3 4000g) occurred in 6.9% and 7.9% of deliveries respectively. There was no difference in patient age (37.5 v 37.0, p¼0.91), GA at delivery (39w0d v 38w6d, p¼0.96), and BW (3350g v 3283.5g, p¼0.50), between PRG and NAT cycles. The PTB (8.8% vs 5.1%; p¼0.17) and LBW (8.0% vs 3.3%; p¼0.62) rates did not differ by protocol, independent of age, past medical history (PMH) and GA (PTB p¼0.99, LBW p¼0.13). The overall composite complication rate was 6.3%. PRG cycles had more complications compared to NAT (8.1% vs 0.6%; p<0.01) even when controlled for by age, PMH and GA (p<0.01). Excluding DE, the complication rate was 6.0%, still higher in PRG cycles (7.8% vs 0.7%, p<0.01).CONCLUSIONS: There is no difference in PTB or LBW rates by cycle protocol after single euploid FET. However, PRG cycles had a higher rate of complications. Further investigation, with larger cohorts, is needed to understand the differences with individual complications.References: 1. Penzias A, Bendikson K, Butts S, et al. The use of preimplantation genetic testing for aneuploidy (PGT-A): a committee opinion. Fertility and Sterility. 2018. 109 (3): 429 -436.SUPPORT: None.