Hemodynamic findings in normotensive women with small for gestational age and growth restricted fetuses

INTRODUCTION: Fetal growth restriction (FGR) in most instances results as a consequence of primary placental dysfunction due to inadequate trophoblastic invasion. Maternal cardiac maladaptation to pregnancy has been proposed as a possible determinant of placental insufficiency and impaired fetal growth. This study aimed to compare the maternal hemodynamic parameters between normotensive women with small-for-gestational age (SGA) and FGR fetuses and to evaluate their correlation with neonatal outcome.MATERIAL AND METHODS: observational cohort study including singleton pregnancies referred to our tertiary care center due to fetal smallness. At the time of diagnosis, fetuses were classified as SGA or FGR according to the Delphi consensus criteria and pregnant women underwent hemodynamic assessment by using cardiac output monitor (USCOM 1A Ltd). A group of women with singleton uncomplicated pregnancies ≥35 weeks of gestation were recruited as controls. Cardiac output, systemic vascular resistance, stroke volume and heart rate were measured and compared among the three groups (controls vs. FGR vs. SGA). The correlation between antenatal findings and neonatal outcome was also evaluated by multivariate logistic regression analysis.RESULTS: 51 women with fetal smallness were assessed at 34.8±2.6 weeks. SGA and FGR were diagnosed in 22 and 29 cases, respectively. The control group included 61 women assessed at 36.5±0.8 weeks of gestation. Women with FGR had a lower cardiac output -Z score (respectively, -1.3±1.2 vs. -0.4±0.8 vs. -0.2±1.0; p<.001) and a higher systemic vascular resistance Z-score compared with both SGA and controls (respectively, 1.2±1.2 vs. 0.2±1.1 vs. -0.02±1.2; p<.001), while no difference in the hemodynamic parameters was found between women with SGA and controls. The incidence of NICU admission did not differ between SGA and FGR fetuses (18.2% vs 41.4%; p=0.13), however FGR had a longer hospitalization compared to SGA fetuses (14.2±17.7 vs. 4.5±1.6 days; p=0.02). Multivariate analysis showed that the cardiac output Z-score at diagnosis (p=0.012) and the birthweight Z-Score (p= 0.007) were independent predictors of the length of neonatal hospitalization.CONCLUSIONS: Different maternal hemodynamic profiles characterize women with SGA or FGR fetuses. Furthermore, a negative correlation was found between the maternal cardiac output and the length of neonatal hospitalization.