Central haemodynamics in normal pregnancy: A prospective longitudinal study

Objective: To conduct a longitudinal evaluation of the central haemodynamic adaptations of normal pregnancy. Methods: This was a prospective longitudinal study involving healthy, normotensive women who were having an uncomplicated, singleton pregnancy. Brachial and central SBP, DBP, mean arterial pressure (MAP), brachial and central pulse pressure (PP), aorta-to-brachial pulse pressure amplification (AMPA-B), heart rate (HR), augmentation index adjusted for HR (AIx75), carotid- femoral pulse wave velocity (cfPWV) and cardiac output (CO) were measured at a mean gestational age of 14, 24 and 36 weeks. Results: One hundred women were followed prospectively throughout pregnancy. Brachial and central SBP, DBP and MAP decreased slightly in early gestation, followed by a significant increase in late gestation (P<0.05). Brachial PP was lowest in the final trimester (P1/40.011) whereas central PP remained unchanged, resulting in a significant decrease in AMPA-B (P<0.001). HR and AIx75 rose continuously throughout pregnancy (P<0.001). A significant fall in cfPWV was observed mid-pregnancy, which remained significant after adjustment for MAP and HR (P<0.05). CO rose mid-pregnancy, before returning to baseline values by week 36 of gestation (P<0.05). Conclusion: To our knowledge, this is the largest prospective study to evaluate several central haemodynamic parameters in normotensive pregnancies, including adjusted-AIx and the gold-standard cfPWV. These data are a necessary foundation for the establishment of pregnancy-specific reference values and provide reference data for future trial design.