Longitudinal Changes in Maternal Cardiovascular Function During Normal and Hypertensive Pregnancies in North West Nigeria: An Echocardiographic Cohort Study

Pregnancy induces significant adaptations in maternal cardiovascular function, and these adaptations are disrupted in hypertensive disorders of pregnancy, with the Nigerian haemodynamic phenotype potentially differing from well-characterised European cohorts due to distinct cardiovascular risk backgrounds. This dissertation characterises longitudinal maternal cardiovascular changes by serial echocardiography in normal and hypertensive pregnancies at Aminu Kano Teaching Hospital and Usmanu Danfodiyo University Teaching Hospital, North West Nigeria. A prospective cohort enrolled 150 normotensive and 100 hypertensive (gestational hypertension and preeclampsia) singleton pregnancies. Serial echocardiography was performed at 12 to 16 weeks, 24 to 28 weeks, 34 to 36 weeks, and six weeks postpartum. Parameters measured included cardiac output, stroke volume, total vascular resistance, left ventricular mass index, left ventricular ejection fraction, and tissue Doppler-derived diastolic function indices. Normotensive pregnancies showed the expected high-output, low-resistance haemodynamic pattern by 24 weeks. Preeclamptic pregnancies demonstrated a fundamentally different haemodynamic pattern with higher total vascular resistance at all gestational ages compared to normotensives, present even before clinical hypertension onset. Left ventricular hypertrophy was documented in 38 percent of preeclamptic women by 36 weeks, compared to 8 percent in normotensives. Subclinical diastolic dysfunction persisted in 24 percent of preeclamptic women at six weeks postpartum. The dissertation provides original cardiovascular phenotyping data from North West Nigerian hypertensive pregnancies and informs postpartum cardiac surveillance recommendations. Keywords: maternal cardiovascular function, preeclampsia, echocardiography, North West Nigeria, haemodynamics