Role of low placental share in twin-twin transfusion syndrome complicated by intrauterine growth restriction.

ABSTRACT

OBJECTIVES: Prior studies have demonstrated that donor twin survival following treatment of twin-twin transfusion syndrome (TTTS) was highly associated with donor intrauterine growth restriction (IUGR). Here, we hypothesized that donor IUGR may be attributed in part to low placental share. STUDY DESIGN: The study population consisted of all patients who underwent laser treatment for TTTS at a single institution between 2006-2010. Only those pregnancies with dual survival at birth were included so that placental share information could be interpreted. We examined the relationships between Quintero Stage (with separate analysis of Stage III patients with critically abnormal donor Doppler findings) and low placental share (defined as ≤ 30%) with IUGR (<10th percentile) using chi-square analysis and multivariable logistic regression modeling. RESULTS: Of 210 patients treated, 159 (75.7%) had dual survivors at birth. Of these, placental share was documented in 90 cases (56.6%). Twenty-seven (30.0%) had low placental share, and 37 (41.1%) had IUGR. IUGR was associated with low placental share (63.0% vs. 31.7%, P = 0.0116). IUGR was also associated with Stage III patients (57.4% vs. 23.3%, P = 0.0021), and in particular with Stage III patients with donor involvement (77.8% vs. 25.4%, P < 0.0001). In logistic regression modeling, both low placental share and Stage III with donor involvement were independent risk factors for IUGR (OR = 3.5 [1.2-10.3], P = 0.0206, and OR = 10.1 [3.3-30.6], P < 0.0001, respectively). CONCLUSIONS: Donor IUGR in TTTS pregnancies appears to be associated, in part, with low placental share.