The impact of obesity on haemodynamic profiles of pregnant women beyond 34 weeks' gestation

Objective: We aimed to compare the haemodynamic profiles of obese and non-obese pregnant women, alongside describing the haemodynamic changes that occur in hypertensive disorders of pregnancies with an Appropriate for Gestational Age Fetus (HDP-AGA) beyond 34 weeks' gestation.Study design: In this prospective case-control study, maternal haemodynamic assessment was carried out by a trained operator using an UltraSonic Cardiac Output Monitor during a routine clinical assessment after 34 weeks of gestation. Indexed and non-indexed parameters were evaluated.Main outcome measures: Maternal hemodynamic parameters.Results: Obese and non-obese women did not differ for non-indexed parameters (Cardiac Output, Stroke Volume, Systemic Vascular Resistance). Using indexed parameters, corrected for Body Surface Area, obese women presented significantly lower Cardiac Index z-score (-0.23 +/- 0.5 vs 0.26 +/- 1.2; p = 0.004), Stroke Volume Index z-score (-0.27 +/- 0.8 vs 0.31 +/- 1.0; p < 0.0001) and significantly higher Systemic Vascular Resistance Index (0.16 +/- 0.8 vs -0.36 +/- 0.7; p < 0.0001). In obese women, HDP-AGA (n = 19) had significantly higher Systemic Vascular Resistance Index z-score (1.26 +/- 1.7 vs 0.16 +/- 0.8; P = 0.009) and significantly lower Stroke Volume Index (-0.68 +/- 0.8 vs -0.27 +/- 0.8; 0.049).Conclusion: Using indexed parameters, differences in haemodynamic profiles between obese and non obese women can be highlighted. Obese women seem to present a cardiac maladapation to the pregnancy (reduced cardiac index and stroke volume and increased vascular resistance) that could explain the increased risk of complications in this subgroup.