To evaluate the effect of the COVID-19 pandemic state on early, 1st trimester pregnancies, in light of a link described between war-induced stress and adverse pregnancy outcomes. Retrospective cohort study conducted in a University fertility center. All 1ST trimester viability scans done since the COVID-19 shut down, March13-May 6, 2020 (Study group), and between March 1-May 17, 2019 (pre-pandemic Control), were reviewed. Early 1st trimester pregnancy outcomes (Viable pregnancy, Arrested pregnancy including biochemical pregnancy loss and miscarriage, and ectopic pregnancy (EP)) were measured. A multivariate analysis was performed to control for significant confounders. Power analysis revealed that a sample size of 58 patients per group has a 90% power with a 15% difference in outcomes and α=5%. The study group denied symptoms of COVID-19. 113 women were scanned in the study, and 172 in the control periods (5-11 weeks gestational age). The groups had similar demographics, gestational history, fertility diagnosis and treatment characteristics (Table). No significant differences were noted in the rate of recurrent pregnancy loss (RPL). Viable clinical pregnancy rates were not different between the groups (76.1% vs. 80.2% in the pandemic and pre-pandemic groups p= 0.41). No significant difference was seen in number of 1st trimester miscarriage (14.2% vs 12.8% p=0.76), biochemical pregnancies (3.5% vs 1.7% p=0.34), or in total miscarriage rate (22.1% vs 16.9% p=0.32), nor in EP rates (0.9% vs 2.3% p=0.36) Mean serum TSH levels were higher in the control but fell in the normal range for both groups. Use of donor sperm was higher in the control and may have favored lower miscarriage rates in that group. The COVID-19 pandemic environment does not seem to affect early first-trimester miscarriage rates in asymptomatic patients.Tabled 1CharacteristicStudy(n=113)Pre-pandemic Control (n=172)P-valueFemale Age, Years, mean±SD36.5 ± 4.537.2 ± 5.40.28RPL History, N(%)15 (13.3)15 (8.7)0.22Fertility diagnosis, N(%)Unexplained24 (21.4)32 (19.6)0.21Male Factor36 (32.1)58 (35.6)Tubal factor5 (4.5)11 (6.8)Polycystic ovarian syndrome21 (18.8)25 (15.3)Decreased ovarian reserve23 (20.5)20 (12.3)Endometriosis1 (0.9)4 (2.5)Base line testing, median(IQR)AMH ng/ml2.5 (1.0 – 4.4)2.5 (1.2 – 5.4)0.75TSH mIU/L1.3 (0.9 – 1.8)1.7 (1.2 – 2.3)0.001Antral follicular count (AFC)16 (9 – 29)14 (9 – 25)0.27Total motile sperm count, median(IQR)18 (6 – 43)12 (5 – 47)0.23Sperm donation, N (%)2 (1.8)17 (9.9)0.01Pregnancy, N (%)Spontaneous34 (30.1)54 (31.4)0.97IUI34 (30.1)51 (29.7)IVF45 (39.8)67 (38.9)ICSI (percentage of IVF patients)31 (79.5)52 (77.6)0.82Blastocyst transferred39 (86.7)56 (83.6)0.65 Open table in a new tab