Is maternal anemia associated with small placental volume in the first trimester?

Aim: To clarify whether maternal anemia could reduce placental volume in the early gestation. Methods: A prospective cross-sectional study was conducted. Consecutive women who visited at 11-13 + 6 weeks' gestation were enrolled. Subjects were divided into two groups by maternal hemoglobin concentration. Cases with maternal anemia were defined as a hemoglobin level less than 11 g/dl on a blood test (cases), and the others were defined as controls. An ultrasound examination was performed to measure the placental volume and the uterine arterial blood flow. The three-dimensional volume of the placenta using virtual organ computer-aided analysis (VOCAL) technique was acquired by transabdominal ultrasonography. Placental volumes were compared in women with and without anemia. Results: 31 cases and 486 controls were analyzed. Maternal characteristics were not different between two groups except anemia. Placental volumes were 63.6 ± 22.2 and 60.9 ± 22.8 cm³ (ns), uterine arterial RIs were 0.7 ± 0.1 and 0.8 ± 0.1 (ns), and PIs were 1.7 ± 0.5 and 1.8 ± 0.6 (ns) in cases and controls, respectively. Conclusions: Maternal anemia was not associated with reduced placental volume and uterine arterial Doppler wave form at 11-13 weeks' gestation.