Reference values for fetal Doppler-based cardiocirculatory indices in monochorionic-diamniotic twin pregnancy.

BACKGROUND: Placental anastomoses in monochorionic diamniotic (MCDA) twin pregnancy have a major impact on fetal circulation. This study was designed to define reference ranges of cardiac and vascular Doppler indices in MCDA twin pregnancies. METHODS: This cross-sectional study included 442 uncomplicated MCDA twin fetuses undergoing Doppler ultrasonography at 18-35 weeks of gestation. Left and right myocardial performance index (LV-MPI, RV-MPI), E/A ratio of atrioventricular valves, pulsatility indices of umbilical artery, middle cerebral artery (MCA), and ductus venosus (DV), cerebroplacental ratio, peak systolic velocity of MCA, S/a ratio of DV, and early diastolic filling time of ductus venosus (DV-E) were evaluated under standardized settings. The equation models between Doppler indices and gestational age (GA) were fitted. After adjustment for GA, the correlations between MPI and fetal heart rate (FHR), and between MPI and DV indices were analyzed. RESULTS: Estimated centiles of Doppler indices were derived as a function of GA, being distinct in values from those of singletons. There was no correlation between GA-adjusted MPI and FHR. DV-E was inversely related to LV-MPI. CONCLUSIONS: MCDA twins showed significant changes in some Doppler indices throughout gestation with quantitative differences from singletons, emphasizing the importance of MC twin-specific reference values for clinical application. Further adjustment of MPI for FHR was unnecessary. DV-E is a vascular index indirectly representing fetal diastolic function.

Associated factors of blood transfusion for Caesarean sections in pure placenta praevia pregnancies.

INTRODUCTION: This study aimed to evaluate associated factors of blood transfusion for Caesarean sections in pure placenta praevia pregnancies. METHODS: A case-control study was conducted among 405 pregnant women with placenta praevia who underwent Caesarean delivery between August 2004 and December 2013. 135 of the women received blood transfusions. Another 270 women who did not receive any blood transfusion were randomly selected and served as controls. Maternal demographic data, reproductive history, antepartum profiles and obstetric outcomes were compared between the two groups. RESULTS: Women in the case group were significantly more likely to be multiparous, deliver at a gestational age of less than 37 weeks, have a prior Caesarean delivery, experience preoperative bleeding and anaemia, and have major and anterior placenta praevia (p < 0.05). Multivariate analysis demonstrated that significant, independently associated factors of blood transfusion were: previous Caesarean section (adjusted odds ratio [OR] 2.30, 95% confidence interval [CI] 1.36-3.90), anterior placenta praevia (adjusted OR 2.30, 95% CI 1.15-4.60), major placenta praevia (adjusted OR 2.39, 95% CI 1.34-4.22), preoperative bleeding of more than 250 mL (adjusted OR 6.11, 95% CI 2.35-15.90), preoperative anaemia (adjusted OR 2.31, 95% CI 1.34-4.00) and emergency Caesarean section (adjusted OR 2.14, 95% CI 1.08-4.22). CONCLUSION: Previous Caesarean section, anterior placentation, major placenta praevia, preoperative bleeding of more than 250 mL, preoperative anaemia and emergency Caesarean section were independent factors that increased the risk of blood transfusion for Caesarean section in pure placenta praevia pregnancies.