Potential of ultrasound diagnostics in an experimental model of fetal growth restriction

Objective: This study aimed to evaluate the effectiveness of an experimental model of fetal growth restriction (FGR) during the intrauterine stage, using ultrasound tracking of fetal biometric parameters and Doppler measurements in Oryctolagus cuniculus rabbits.

Materials and methods: The study included 16 female Oryctolagus cuniculus rabbits (eight for modeling early-onset FGR and eight for late-onset FGR). Ultrasound examinations were conducted on days 20th and 27th days of gestation, with assessment of the head circumference (HC), abdominal circumference (AC), femur length (FL), and pulsatility index (PI) of the umbilical cord artery.

Results: On the 20th day of gestation, the early-onset FGR experimental group exhibited the lowest values of HC (41.0 [IQR 39.5–42.1] mm), AC (48.8 [IQR 46.7–49.7] mm), and FL (4.7 [IQR 4.68–4.82] mm) compared to the control group (p<0.001). Additionally, fetuses from the experimental FGR group displayed an increase in PI in the umbilical cord artery compared with the control group (1.87 versus 1.56, respectively, p<0.001). A similar trend was observed on the 27th day of gestation. All fetal biometric parameters (HC, AC, and FL) were significantly reduced in early-onset FGR fetuses compared to both the control and late-onset FGR groups. Moreover, there was an increase in cord artery PI in early-onset FGR fetuses (both experimental (2.48, IQR 2.15–2.75) and control groups (2.44, IQR 2.30–2.56)) when compared to the late-onset FGR model (p<0.001). When modeling late-onset FGR, an increase in PI in the umbilical cord artery was observed in the experimental group compared to that in the control group (1.83 versus 1.57, respectively, p<0.001).

Conclusion: Selective ligation of uteroplacental vessels is an effective method for modeling FGR in rabbits, and ultrasound examination during the prenatal stage confirms the success of the operation and the presence of severe placental insufficiency.