F3. Cardiac output and total peripheral resistance in pregnancies with fetal growth restriction

Abstract

Introduction: This pilot study aims to compare cardiac output (CO) and total peripheral resistance (TPR) in pregnancies with fetal growth restriction (FGR) with healthy normal third trimester of pregnancies. Most studies previously done on cardiac parameters in pregnancy focused mainly on pre-eclampsia (PE) and FGR with PE, but not in normotensive FGR women.

Methods: Eight pregnancies with FGR (AC < 10th percentile with raised umbilical PI) in the third trimester (27–35 weeks gestation) compared with 42 uncomplicated ongoing pregnancies within similar gestation bands. CO was measured non-invasively using INNOCOR inert gas re-breathing technique, with the participant standing upright. TPR was measured by the Vicorder device with women in the left lateral position. Unpaired t-test is used to calculate the p values among these groups.

Results: Mean CO in pregnancies with FGR was 4.99 l/min and 5.65 l/min in healthy pregnancies (p = 0.08). Mean TPR (dyn.s.cm⁻⁵) was 0.95 in FGR and 0.83 in healthy pregnancies (p = 0.05). See Charts.

Conclusions: There is no significant difference in CO between the two groups but TPR is higher in fetal growth restriction. This would support the theory of a hypodynamic circulation affecting these pregnancies, suggesting maternal cardiovascular maladaptation. It is worth noting that the numbers of patients in this early work are still small; however, the general trend does reflect that of the finding of Valensise et al. [1]. We plan to determine CO and TPR in relation to both gestation of onset and clinical deterioration prompting delivery. By characterizing these cardiovascular changes and their timing might allow for future intervention to modify cardiovascular function and plan optimal time of delivery.