BACKGROUND

The maternal cardiovascular profile of patients who develop late fetal growth restriction has yet to be well characterized, however, a subclinical impairment in maternal hemodynamics and cardiac function may be present before pregnancy and may become evident because of the hemodynamic alterations associated with pregnancy.

OBJECTIVE

This study aimed to investigate if maternal hemodynamics and the cardiovascular profile might be different in the preclinical stages (22-24 weeks' gestation) in cases of early and late fetal growth restriction in normotensive patients.

STUDY DESIGN

This was a prospective echocardiographic study of 1152 normotensive nulliparous pregnant women at 22 to 24 weeks' gestation. The echocardiographic evaluation included morphologic parameters (left ventricular mass index and relative wall thickness, left atrial volume index) and systolic and diastolic maternal left ventricular function (ejection fraction, left ventricular global longitudinal strain, E/A ratio, and E/e' ratio). Patients were followed until the end of pregnancy to note the development of normotensive early or late fetal growth restriction.

RESULTS

Of the study cohort, 1049 patients had no complications, 73 were classified as having late fetal growth restriction, and 30 were classified as having early fetal growth restriction. In terms of left ventricular morphology, the left ventricular end-diastolic diameter was greater in uneventful pregnancies (4.84±0.28 cm) than in late (4.67±0.26 cm) and in early (4.55±0.26 cm) (P<.001) fetal growth restriction cases, whereas left ventricular end-systolic diameter was smaller in uneventful pregnancies (2.66±0.39 cm) than in late (2.83±0.40 cm) and in early (2.82±0.38 cm) (P<.001) fetal growth restriction cases. The relative wall thickness was slightly higher in early (0.34±0.05) and late (0.35±0.04) fetal growth restriction cases than in uneventful pregnancies (0.32±0.05) (P<.05). In terms of systolic left ventricular function, at 22 to 24 weeks' gestation, cardiac output was higher in uneventful pregnancies (6.58±1.07 L/min) than in late (5.40±0.97 L/min) and in early (4.76±1.05 L/min) (P<.001) fetal growth restriction cases with the lowest values in the early-onset group. Left ventricular global longitudinal strain was lower in appropriate for gestational age neonates (-21.6%±2.0%) and progressively higher in late (-20.1%±2.2%) and early (-18.5%±2.3%) (P<.001) fetal growth restriction cases. In terms of diastolic left ventricular function, the E/e' ratio showed intermediate values in the late fetal growth restriction group (7.90±2.73) when compared with the appropriate for gestational age group (7.24±2.43) and with the early fetal growth restriction group (10.76±3.25) (P<.001). The total peripheral vascular resistance was also intermediate in the late fetal growth restriction group (1300±199 dyne·s·cm) when compared with the appropriate for gestational age group (993±175 dyne·s·cm) and the early fetal growth restriction group (1488±255 dyne.s.cm) (P<.001).

CONCLUSION

Early and late fetal growth restriction share similar maternal hemodynamic and cardiovascular profiles with a different degree of expression. These features are already present at 22 to 24 weeks' gestation and are characterized by a hypodynamic state. The degree of these cardiovascular changes may influence the timing of the manifestation of the disease; a hypovolemic, high resistance, low cardiac output state might be associated with early-onset fetal growth restriction, whereas a milder hypovolemic state seems to favor the development of the disease in the final stages of pregnancy.