17 Is maternal blood pressure during pregnancy associated with infant arterial stiffness?

Abstract

Introduction In adults, arterial stiffness measured by pulse wave velocity (PWV) is regarded as a predictor of cardiovascular disease [1]. This association is less well established in infants, however. Infant and childhood vascular development is dependent on several factors related to the pregnancy, including maternal blood pressure (BP) with one study finding an inverse relationship between BP and neonatal aortic PWV at 1–3days [2]. Objective To assess the association between maternal BP in pregnancy and infant brachio-femoral PWV at age 2–6weeks. Methods The Baby VIP study recruited mother-baby pairs from postnatal wards at Leeds Teaching Hospitals NHS Trust. PWV was measured non-invasively in 284 babies at a home visit 2–6weeks after recruitment using the Vicorder device. Maternal BP at booking and at 36weeks gestation, along with other co-variables, were collected from delivery and antenatal notes. Multivariable linear regression models were used to link maternal systolic and diastolic BPs, and BP change from booking to 36weeks with PWV. Results At booking, the mean maternal systolic BP was 112mmHg (standard deviation (s.d) 12) and diastolic BP was 67mmHg (s.d 10). At 36weeks gestation, mean maternal systolic BP was 116.3mmHg (s.d 15) and diastolic BP was 70.8mmHg (s.d 12). Mean infant PWV was 6.7m/s (s.d 1.3). PWV was not significantly associated with hypertension in pregnancy (at booking or at 36weeks) in univariate analysis, where hypertension was defined as systolic BP⩾140mmHg or diastolic BP⩾90mmHg, or a rise in systolic BP of ⩾30mmHg or rise in diastolic BP of ⩾15mmHg from booking to 36weeks ( p >0.05). There was no association between infant PWV and maternal systolic BP at 36 weeks assessed as a continuous variable (regression co-efficient 0.003m/s, 95% confidence intervals (CI) −0.01, 0.01, p =0.6) adjusted for pregnancy factors including maternal age, ethnicity, history of gestational diabetes, pre-eclampsia, anaemia, BMI and infant factors including baby's age, position, whether sleep or awake at the time of measurement, and prematurity. There was no association between infant PWV and a ⩾30mmHg rise in systolic BP at 36 weeks from booking (adjusted regression co-efficient −0.4m/s, 95% CI −1.1, 0.41, p =0.4). Conclusions This study has shown that there is no evidence of any associations between infant PWV and hypertension or maternal BP during pregnancy. We demonstrate the feasibility and acceptability of using PWV in early infancy. However, further studies are required to determine the predictors of infant PWV, the significance and long term implications of PWV measurements in infants.