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

Abstract

Introduction Fetal growth restriction (FGR) in most instances is 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 An 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 using a cardiac output monitor. A group of women with singleton uncomplicated pregnancies ar ≥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 A total of 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 (respectively, 1.2 ± 1.2 vs 0.2 ± 1.1 vs −0.02 ± 1.2; P < .001) compared with both SGA and controls, whereas no difference in the hemodynamic parameters was found between women with SGA and controls. The incidence of neonatal intensive care unit admission did not differ between SGA and FGR fetuses (18.2% vs 41.4%; P = .13), but FGR fetuses had a longer hospitalization compared with SGA fetuses (14.2 ± 17.7 vs 4.5 ± 1.6 days; P = .02). Multivariate analysis showed that the cardiac output Z‐score at diagnosis (P = .012) and the birthweight Z‐score (P = .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.

An update on maternal cardiac hemodynamics in fetal growth restriction and pre‐eclampsia

“…Additionally, several studies also demonstrated differences in the hemodynamic profile of normotensive women with small‐for‐gestational age or FGR compared to uncomplicated pregnancies. In such context, fetal smallness was also associated with reduced CO and increased PVR were associated with fetal smallness, 6,11–20 which further supports the hypothesis of an inadequate maternal cardiovascular adaptation to the pregnancy as a determinant of placental dysfunction.…”

“…More specifically, FGR was shown to be associated with lower CO and higher PVR compared to SGA, furthermore the hemodynamic profile was shown to be similar in mothers diagnosed with a SGA fetus and uncomplicated pregnancies. 11,13,20 Furthermore, the reduced CO recorded in FGR compared to SGA was shown to be determined by a reduction in the HR but not in the SV. 20 A summary of the maternal hemodynamics changes occurring during normal pregnancy and in placenta-related pathologies is shown in Figure 1.…”

Maternal Low Volume Circulation Relates to Normotensive and Preeclamptic Fetal Growth Restriction

“…The nature of this pathophysiologic pathway is in line with the reported increased serum concentrations of atrial natriuretic peptide ( 52 ) and copeptin/vasopressin in PE ( 53 ) and with the impaired expansion of maternal plasma volume in EPE ( 9 ). The early gestational onset of this phenomenon is also supported by the shallow, but significant, rise of serum hemoglobin concentrations and hematocrit in the first trimester of pregnancies destined to develop EPE ( 31 , 54 , 55 ) but not in those eventually leading to FGR ( 56 ). As explained above and illustrated in Figure 1 , FGR pregnancies show a normal rise of plasma volume and total body water, superimposed upon constitutionally low body water already present before conception.…”

“…This observation has also been reported by others ( 29 ) and linked to a condition of low CO that is already present before conception ( 17 ). Low CO in FGR pregnancies mainly results from low SV ( 30 , 31 ) and to a lesser degree from low HR ( 32 , 33 ). Throughout an uncomplicated pregnancy, the fraction of CO deviated to the uterus doubles from 6 to 12% ( 34 ) and is achieved by an increase of (distal) internal iliac artery impedance in concert with a reduction of uterine artery impedance ( 35 ).…”

Fetal growth restriction and stillbirth: Biomarkers for identifying at risk fetuses

“…Increased peripheral vascular resistance in mothers with chronic hypertension is highly predictive of birthweight and FGR by mid-pregnancy (Vasapollo et al, 2022), and lower cardiac output and increased systemic resistance was observed with FGR. These parameters were also a strong indicator of subsequent neonatal hospitalization (Di Pasquo et al, 2021). Reduced maternal perfusion can lead to lesions related to hypoxia.…”