Early third‐trimester maternal cardiac function and morphometry in high‐risk pregnancies that subsequently developed fetal growth restriction and/or pre‐eclampsia

Objective To evaluate maternal cardiovascular function and cardiac morphology in early third‐trimester pregnancies at high risk for fetal growth restriction (FGR) and compare findings between pregnancies that subsequently developed FGR and/or pre‐eclampsia (PE) and uncomplicated pregnancies. Methods This prospective cohort study included singleton pregnancies at high risk for FGR referred to the Maternal–Fetal Medicine Department at the Hospital Clinic of Barcelona, Barcelona, Spain, between August 2022 and August 2024, for a routine second‐trimester fetal anomaly scan. The patients were assessed between 27 + 0 and 28 + 6 weeks' gestation and were only included in the analysis if they did not have a diagnosis of FGR or PE at the time of evaluation; those who subsequently developed FGR and/or PE were identified during follow‐up. Maternal echocardiography was performed to assess cardiac output (CO), stroke volume (SV), systemic vascular resistance (SVR) and structural parameters including left ventricular (LV) wall thickness and chamber volumes. Results were compared between pregnancies that subsequently developed FGR (with or without PE), pregnancies that subsequently developed isolated PE and uncomplicated pregnancies. Multivariable analysis was performed using quantile regression of the medians for CO and SVR, adjusted for body mass index (BMI), with FGR and PE assessed independently. Results A total of 948 patients were included in the final analysis, of whom 129 developed FGR and/or PE (including 59 that developed FGR (with or without PE) and 70 that developed isolated PE) and 819 had uncomplicated pregnancies. Median mean arterial pressure (MAP) was higher in the FGR (with or without PE) group (82.0 mmHg) and the isolated‐PE group (84.8 mmHg) than in the uncomplicated group (79.7 mmHg; P = 0.027 and P < 0.001, respectively), with the isolated‐PE group showing the highest MAP values (isolated PE vs FGR (with or without PE), P = 0.047). Median heart rate was elevated in the isolated‐PE group (82.5 bpm) compared with the FGR (with or without PE) group (77.0 bpm; P = 0.03). In the multivariable analysis, FGR and PE were associated independently with lower CO and higher SVR prior to their development. Median SV was reduced in the FGR (with or without PE) group (59.7 mL) and the isolated‐PE group (61.1 mL) compared with the uncomplicated group (64.2 mL; P = 0.030 and P = 0.016, respectively). Median BMI‐indexed CO was also lower in the FGR (with or without PE) group (0.18 (L/min)/(kg/m 2 )) and the isolated‐PE group (0.17 (L/min)/(kg/m 2 )) compared with the uncomplicated group (0.19 (L/min)/(kg/m 2 ); P = 0.005 and P = 0.001, respectively). Median SVR was elevated in the FGR (with or without PE) group (1393 dynes × s/cm 5 ) and the isolated‐PE group (1339 dynes × s/cm 5 ) compared with the uncomplicated group (1252 dynes × s/cm 5 ; P < 0.001 and P = 0.01, respectively). Compared with the uncomplicated group, the isolated‐PE group showed greater median LV myocardial thickness at end diastole (0.50 vs 0.47 cm; P = 0.003), interventricular septal thickness at end diastole (0.92 vs 0.89 cm; P = 0.031), posterior wall thickness at end diastole (0.98 vs 0.94 cm; P = 0.013) and relative wall thickness (0.45 vs 0.42; P = 0.001). Moreover, the FGR (with or without PE) group had a smaller median LV end‐diastolic diameter (4.27 cm) compared with the uncomplicated group (4.48 cm; P = 0.003), indicating that preload may be reduced in patients who developed FGR (with or without PE). LV mass indexed for BMI was similar across groups. Conclusions Maternal cardiovascular alterations may precede the development of FGR and PE and differ by phenotype. Pregnancies that subsequently developed FGR and/or PE showed reduced CO, but those that developed FGR reflected lower preload without tachycardia, while those that developed isolated PE showed hypertensive features with a compensatory rise in heart rate. Maternal echocardiography may aid early risk stratification and guide tailored surveillance and therapy in pregnancies at high risk for FGR.