Pregnancy outcomes and placental characteristics of selective intrauterine growth restriction with or without twin anemia polythemia sequence

Introduction: To investigate differences in the pregnancy outcomes and placental characteristics of selective intrauterine growth restriction (sIUGR) with or without twin anemia polythemia sequence (TAPS).

Methods: sIUGR patients were assigned into two groups based on the occurrence of TAPS. The pregnancy outcomes and placental characteristics were compared. A diameter of ≥2 mm was defined as thick anastomosis.

Results: The prevalence of artery-to-artery (AA) (45.5% vs 88.6%, P = 0.002) and thick AA (0% vs 53.5%) in TAPS group were lower than non-TAPS group. The overall diameter of AA (0.5 (0.4-1.3) vs 2.5 (0.3-7.1) mm, P = 0.001) in TAPS group was smaller than non-TAPS group. The prevalence of thick artery-to-vein (AV) (0% vs 36.0%) in TAPS group was lower than non-TAPS group. Also, the overall diameter of AV (0.9 (0.6-2.1) vs 4.8 (0.3-17.8) mm, P < 0.001) in TAPS group was smaller than non-TAPS group. The total quantity (2 (1-6) vs 6 (1-16), P = 0.001), and the overall diameter of anastomoses (1.1 (0.6-4.7) vs 7.5 (0.5-22.4) mm, P < 0.001) were smaller in TAPS group than non-TAPS group. The placental territory discordance ratio of TAPS group was smaller than non-TAPS group (0.39 (0.13-0.56) vs 0.56 (0.01-0.88), P = 0.008). The umbilical cord insertion distance ratio in TAPS group was higher than non-TAPS group (0.81 ± 0.12 vs 0.57 ± 0.20, P < 0.001).

Discussion: The placental anastomoses of sIUGR with TAPS were small. sIUGR with TAPS had smaller differences in placental share and larger distances between umbilical cord insertions.