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OP29.04: Placental vascularization by three‐dimensional power Doppler in the twin‐to‐twin transfusion syndrome

Objective: To describe the longitudinal changes in maternal cardiac function during uncomplicated twin pregnancy. Materials and methods: In a series of twin viable pregnancies cardiac output (CO) and total vascular resistance (TVR) were longitudinally calculated at 20–23, 26–29 and 30–33 weeks of gestation. Cardiac output was measured by continuous-wave Doppler at the aortic valve. Patients were excluded with any of the following: delivery prior to 36 completed weeks; ascertained fetal anomalies; history of maternal disease or hypertensive disorder, perinatal death, IUGR of one or both newborns (birthweight < 5th percentile); maternal preeclampsia. In all cases delivery was electively performed by scheduled Cesarean section between 36 and 37 weeks. Results: Overall nine pregnancies were enrolled in the study. Maternal cardiac output significantly increased during pregnancy (6, 04 ± 0, 53 L/min at 20–23 weeks to 6, 92 ± 0, 72 L/min at 26–29 weeks and to 7, 03 ± 0, 80L/min at 30–33 weeks, p = 0,001). This was essentially due to a significant increase in heart rate (83 ± 9, 57 b/min at 20–23 weeks to 96 ± 14, 23 b/min at 26–29 weeks and to 101 ± 17, 04 b/min at 30–33 weeks, p = 0,004), while the stroke volume did not change significantly. On the other hand a non significant trend to fall in TVR (1091 ± 13 at 20–23 weeks, 989 ± 114 at 26–29 weeks, 1001 ± 68 dynes/s/cm5 at 30–33 weeks, p = 0,236) was observed after midpregnancy Conclusion: In uncomplicated twin pregnancies after midgestation maternal cardiac output seems to rise progressively due to increase in heart rate, while TVR do not show significant variations.