Ashraf Jamal - Fetomaternal Department, Shariati Hospital Tehran University of Medical Sciences, Tehran, Iran.
Mahsa Naemi - Fetomaternal Department, Shariati Hospital Tehran University of Medical Sciences, Tehran, Iran.
Laleh Eslamian - Fetomaternal Department, Shariati Hospital Tehran University of Medical Sciences, Tehran, Iran.
Vajiheh Marsoosi - Fetomaternal Department, Shariati Hospital Tehran University of Medical Sciences, Tehran, Iran.
Maryam Moghfeghi - Department of Endocrinology and Female Infertility, Reproductive Biomedicine Research Center, Royan Institute, Tehran, Iran.
Maryam Nurzadeh - Fetomaternal Department, Shariati Hospital Tehran University of Medical Sciences, Tehran, Iran.
Taraneh Geran - Department of Obstetrics and Gynecology, Imam Khomeini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran.
Marjan Ghaemi - Vali-e-Asr Reproductive Health Research Center, Tehran University of Medical Sciences, Tehran, Iran.
Leila Zanbagh - Fetomaternal Department, Shariati Hospital Tehran University of Medical Sciences, Tehran, Iran.

Background: Estimation of the fetal birth weight and diagnosis of small for gestational age in the fetuses of women with gestational diabetes mellitus (GDM) are currently imprecise. Objective: We aimed to evaluate the association between fetal renal artery Doppler indices and neonatal birth weight in women with GDM in late pregnancy. Materials and Methods: This cohort study recruited ۲۴۶ pregnant women from Shariati Hospital in Tehran, Iran, in two GDM and healthy control groups. Participants underwent weekly Doppler ultrasounds in late pregnancy period (۳۷-۴۰ wk) to determine the Doppler indices of the umbilical artery, middle cerebral, and renal arteries. Fetal growth indices including biparietal diameter, abdominal circumference, head circumference, and femur length were also recorded and compared between two groups. Results: Fetal growth indices and estimated fetal weight were not significantly different between the two groups. Neonatal birth weight was significantly higher in the GDM group (p < ۰.۰۰۱). The GDM group had significantly higher renal artery indices (RI: p = ۰.۰۰۷, pulsatility index (PI): p = ۰.۰۳۲, and systolic/diastolic ratio (S/D): p = ۰.۰۰۶) compared to the control group. Also, there was an inverse linear correlation between umbilical indices and birth weight ((PI: p = ۰.۰۱۴), S/D: (p = ۰.۰۰۴)), and between renal artery indices and birth weight ((RI: p = ۰.۰۱۸), PI: p = ۰.۰۱۰) and S/D: p = ۰.۰۲۵)). In the control group, only umbilical artery PI had an inverse linear correlation with birth weight (p = ۰.۰۲۷) and there was no correlation between renal artery indices and birth weight. Conclusion: Using Doppler hemodynamic indices of the renal artery in late pregnancy in women with GDM can be helpful for early detection of hypoxic fetuses, who are at risk of being small for gestational age or having intrauterine growth restriction, even when of normal weight.

Fetus, Gestational diabetes mellitus, Infant, Middle cerebral artery, Renal artery, Doppler ultrasound, Umbilical artery.