OP11.08: Persistence of increased uterine arteries resistance in the third trimester and pregnancy outcome

to evaluate if in patients with increased uterine arteries resistance in the second trimester, the persistence of abnormal uteroplacental Doppler in the third trimester may be related to preeclampsia, preterm birth and low birthweight. nulliparous women with uterine mean resistance index (RI) above the 95th centile for gestational age at 20–22 weeks underwent Doppler interrogation of uterine arteries at 28 weeks. Flow velocity was considered abnormal if mean RI was persistently above the 95th centile for gestational age. The following outcome variables were considered for each case: occurrence of preeclampsia, gestational age at delivery, birthweight. between February 2006 and January 2007 66 women were diagnosed with increased uterine RI in the second trimester, including 40 (60.6%) with a persistent abnormal uteroplacental Doppler at 28 weeks. In the whole group 4 women (6.1%) presented preeclampsia, mean gestational age at delivery was 37.53 ± 3.07 weeks and mean birthweight was 2759 ± 721g (z score − 0.7 ± 1.00 DS). In the group with persistently increased uterine RI in the third trimester compared to controls mean gestational age at delivery (36.57 ± 3.38w vs 39.00 ± 1.72w; P < 0.005) and mean birthweight (2482 ± 727g vs 3186 ± 461g; P < 0.00005) were significantly lower; the z score of birthweight was significantly lower (−1.01 ± 0.99 vs − 0.25 ± 0.83; P < 0.005); the occurrence of preeclampsia was slightly increased although this did not reach statistical significance (3/40 vs 1/26 OR 2.027, CI 95% 0.269–14.808; P > 0.05). in women with increased uterine resistance in the second trimester, the persistence of abnormal uteroplacental Doppler at 28 weeks is associated with an increased risk of obstetric complications, including mostly preterm birth and low birthweight.