Objective To examine the antenatal imaging features, intrapartum findings and early postpartum course of pregnancies with trisomy 21 (T21). Design Ten-year retrospective review Setting A tertiary hospital in the United Kingdom Population Women with a pregnancy affected by T21, who did not have a termination. Methods Women with pregnancies diagnosed with T21 on: antenatal karyotyping; karyotyping of post-mortem tissue and postnatal karyotype samples, from February 2010-2020. Main Outcome Measures Antenatal imaging findings, fetal growth restriction (FGR), birthweight, mode of delivery, and early neonatal outcomes. Results Seventy-six women with a fetus affected by T21 were identified. There were 6 intrauterine deaths, and 70 livebirths. Thirty-eight (50%) had an antenatal diagnosis and twenty-five (33%) had a suspected diagnosis but declined further testing. The diagnosis was unanticipated in 13 (17%). Cardiac anomalies (n=27) were the most common antenatal anomaly. Doppler abnormalities were apparent in 48/73 (68%). Eighteen (25.7%) had ultrasound evidence of FGR. The majority delivered by Caesarean section, and 21.4% of babies weighed below the 3rd percentile at delivery. Fifty-eight (82%) were admitted to the neonatal unit. Forty-three (61%) required respiratory support and fifty-five (78%) either needed naso-gastric feeding or were nil by mouth. Mean PAPP-A values were significantly lower in cases with abnormal Dopplers, FGR, congenital anomalies and with a birthweight below the 10th percentile. Conclusions Fetuses with T21 have high rates of placental insufficiency. FGR and Doppler abnormalities are common. Postnatally, the majority will require respiratory and feeding support. Antenatal counselling and protocols should reflect these risks. Funding None