OP10.08: Postnatal functional echocardiography (fECHO) in neonates with abnormal fetal umbilical artery Doppler (UAD)

Abstract

which in turn may cause less of a rise in heart rate (HR). Uterine artery Doppler (UtAD) provides a method of assessing risk for the development of pre-eclampsia. We examined the relationship between second trimester UtAD pulsatility index (PI), HR and birth weight. Methods: 99 women were recruited from the high-risk obstetric ultrasound clinic in the second trimester; median (± IQR) age and gestation were 33 (29–37) years and 23+6 (23+3–24+4) weeks respectively. Mean values of UtAD PI were recorded. Cardiovascular measurements including HR were performed at a later date (26+5 (25+6–28+0) weeks gestation). Gender specific z-scores were calculated from the unit’s previous 5 years’ births. Results: We found a significant positive correlation between HR and birth weight z-score, r = 0.22 (P = 0.03, 95% CI: 0.02–0.40). This correlation remained when 4 patients taking β-blockers were excluded, r = 0.21 (P = 0.04, 95% CI: 0.01–0.40). An inverse association was found between UtAD PI and HR r = −0.43 (P = 0.0001, 95% CI: 0.01–0.40). Conclusions: The novel finding is that lower second trimester HR is associated with lower birth weight; we hypothesize that this reflects inadequate cardiovascular adaptation to pregnancy. We confirm the previously described effect of HR on UtAD PI. However, it is not possible to determine whether this was a direct effect of HR on UtAD PI, or whether women with abnormal placentation are more likely to have a slower HR. This has obvious implications for predictive models using both UtAD and HR.