The Relationship between the Fetal Volume-Corrected Renal Artery Pulsatility Index and Amniotic Fluid Volume

Association of Amniotic Fluid Volume and Fetal Cardiac and Cerebrovascular Parameters in Fetal Growth Restriction

OBJECTIVES

To investigate the prevalence of oligohydramnios, brain sparing, and cardiac dysfunction among a cohort of fetal growth restriction (FGR).

METHODS

To assess the prevalence of oligohydramnios amongst a large sample of FGR fetuses, we screened a database of ultrasounds of FGR pregnancies from our maternal-fetal medicine clinics (clinical cohort) for diminished amniotic fluid volume. Using a threshold of a maximum vertical pocket (MVP) of <2 cm for "oligohydramnios," and 2 to 3 cm as a "reduced fluid" group, trends of Doppler values and cardiac parameters were assessed from pregnancies in an ongoing research study (comprehensive cohort).

RESULTS

In the clinical cohort, oligohydramnios was identified in only 2/229 (0.8%) and reduced fluid in 19/229 (8%). In the comprehensive cohort, oligohydramnios was seen in 3/126 (2.3%) and reduced fluid in 14/126 (11.1%). A high rate of cardiac and Doppler abnormalities were observed in the oligohydramnios group of the comprehensive cohort. The patients with oligohydramnios had a distinctly different cardiac phenotype with small (2/3 with cardiac area <5th%) (P = 0.01) and round (3/3 with global sphericity index <5th%) (P = 0.02) hearts.

CONCLUSION

Oligohydramnios, when present with FGR, is accompanied by high rates of cerebral and cardiovascular abnormalities.

Comparison of renal artery Doppler parameters of monochorionic diamniotic twin pregnancies with and without twin-to-twin transfusion syndrome

Background

Monochorionic diamniotic (MCDA) twin pregnancies are considered high-risk for several reasons, especially the risk of twin-to-twin transfusion syndrome (TTTS). Renal artery Doppler (RAD) is reported as a useful tool for predicting oligohydramnios in singleton pregnancies. We aimed to compare the RAD indices between MCDA twins with and without TTTS.

Materials and Methods

In this case-control study, all pregnant women aged 18-38 years, with gestational age ≥ 18 weeks, who were referred to two Prenatal Clinics, Alzahra and Beheshti Educational Hospitals, affiliated to Isfahan University of Medical Sciences, Isfahan, Iran, October 2020-March 2022 were enrolled; the women with MCDA twin pregnancies complicated by TTTS (case group, n = 12) and without TTTS (control group, n = 24). For each twin, biometric analysis, fetal weight, and Doppler study of fetal arteries, including RAD, middle cerebral artery (MCA), umbilical artery, and ductus venosus were performed. Peak systolic velocity, Pulsatility index (PI), resistance index (RI), and systole/diastole (S/D) were measured for all arteries.

Results

The donors of the case group had a lower mean MCA S/D (4.48 ± 1.89) than the control group (6.48 ± 1.97) (P = 0.01) and higher mean umbilical parameters, including PI, RI, and S/D (P < 0.05). The recipients of the case group had a lower mean renal PI than the control (P = 0.008) and lower mean MCA PI, RI, and S/D (P < 0.05). The donor group had a higher mean umbilical RI and S/D than the recipient twin, while the mean fetal weight of the recipient group was higher (P < 0.05).

Conclusion

Comparing the RAD parameters between the twins with and without TTTS in the present study did not identify significant results, which rejected the primary hypothesis. Among all RAD parameters, the only significant difference observed in the present study was the lower RAD PI in RT, which cannot suggest this measurement as a valuable tool for the prediction of TTTS in MCDA twins. Therefore, the results of the present study failed to show the additional value of RAD, compared with the conventional Doppler examination of fetal arteries. Further studies are required to prove this conclusion.

Adverse perinatal outcomes in fetuses with severe late-onset fetal growth restriction

OBJECTIVE

To evaluate perinatal outcomes in fetuses with severe late-onset fetal growth restriction.

METHODS

This was a retrospective and observational cohort study in which pregnant women diagnosed with late-onset fetal growth restriction assisted at perinatal maternity birth from 2010 to 2017 were included. The outcomes were intensive care unit (ICU) admission and perinatal complications, such as neonatal death, intraventricular hemorrhage, periventricular leukomalacia, hypoxic-ischemic encephalopathy, necrotizing enterocolitis, bronchopulmonary dysplasia, and sepsis.

RESULTS

We selected 277 pregnant women, of whom 124 newborns (44.76%) went to the ICU. The chance of a newborn needing ICU decreases by 62, 7, and 9% according to an increase of one gestational week, 1 cm of the abdominal circumference, or 1 cm of the amniotic fluid index, respectively. Oligohydramnios increases the risk of going to the ICU by 2.13 times. The increase in the umbilical artery pulsatility index (PI) Doppler increases the chance of ICU admission by 7.9 times. The normal middle cerebral artery PI Doppler and the normal cerebroplacental ratio reduce the risk of ICU admission.

CONCLUSION

The estimated fetal weight, abdominal circumference, and amniotic fluid index diagnosed severe late-onset fetal growth restriction. With the decrease in middle cerebral artery PI Doppler, there is a greater probability of admission to the ICU, with the most common complications being intraventricular hemorrhage and necrotizing enterocolitis.