O114. Maternal cardiovascular changes in pregnancies complicated by small for gestational age neonate with or without maternal hypertension

Abstract

Objective The literature describing the maternal cardiovascular changes in pregnancies complicated by fetal growth restriction and maternal hypertension is limited, conflicting and does not discriminate the two pathologies. The aim of this study was to investigate maternal cardiovascular changes in pregnancies complicated by small for gestational age (SGA) neonates with or without maternal hypertension. Methods This was a prospective case-control study including pregnancies resulted in SGA neonate (n = 159) and a group of uncomplicated pregnancies (n = 473), recruited after 20 weeks’ gestation. The SGA group was further divided according to fetal Doppler to define fetal growth restriction (FGR; n = 51) and maternal hypertension (n = 51). FGR was defined as estimated fetal weight below the 10th centile with abnormal umbilical artery Doppler (pulsatility index [PI] above the 90th centile or absent or reversed end-diastolic flow). Maternal cardiac output (CO), cardiac index (CI), systemic vascular resistance (SVR), systemic vascular resistance index (SVRI) were recorded using the USCOM®, while the augmentation index (AIx) was assessed using the Arteriograph®.Uterine artery (UtA) mean PI was assessed at the same visit. Mann–Whitney test and regression analysis were used for statistical analysis. Results Compared to controls, the SGA pregnancies had significantly lower CO (median 6.08 L/min, IQR 5.31–6.86 vs 6.65 L/min, IQR 5.68–7.79, p = 0.006), but significantly higher SVR (median 1091 dynes-sec/cm5, IQR 998–1359 vs 1040 dynes-sec/cm5, IQR 878–1263, p = 0.008). Both AIx and UtA mean PI were significantly higher in the SGA pregnancies compared to controls (p = 0.002 and p 0.001, respectively). In normotensive SGA, the results were similar (p 0.05). However, after correcting for body surface area, neither cardiac index nor SVR index were significantly different between the two study groups (p = 0.209 and p = 0.139, respectively). In normotensive FGR pregnancies, SVR, AIx and UtA mean PI were significantly higher (p 0.01 for all), while CO was not significantly different (p = 0.429). Conclusion FGR is associated with maternal cardiovascular changes. The conflicting results reported by previous studies could be explained by failure to correct for maternal body surface area, incorrectly labelling SGA pregnancies as FGR, or lack of distinction between FGR with or without maternal hypertension.