Prescriptive Reference Standards of Third-Trimester Cerebroplacental Ratio and Its Physiological Determinants

Area of Science:

• Perinatal medicine
• Fetal physiology
• Obstetric ultrasound

Background:

• The cerebroplacental ratio (CPR) is a key indicator of fetal well-being.
• Establishing accurate reference standards for CPR is crucial for clinical practice.
• Physiological factors influencing CPR require further investigation.

Purpose of the Study:

• To develop reliable reference standards for the cerebroplacental ratio.
• To identify physiological determinants affecting the CPR.
• To validate the constructed CPR reference standards.

Main Methods:

• A cohort of 391 low-risk pregnancies was analyzed.
• Doppler ultrasound measurements of the middle cerebral artery and umbilical artery were obtained.
• Nonparametric quantile regression was used to explore determinants and create standards.

Main Results:

• Maternal body mass index was significantly associated with the 5th centile of the CPR.
• Each unit increase in BMI lowered the 5th CPR centile by approximately 0.014.
• Derived standards showed good agreement in a validation cohort.

Conclusions:

• Methodologically sound prescriptive standards for CPR were established.
• Maternal body mass index is a significant determinant of the lower CPR cutoff.
• These findings aid in optimizing clinical decision-making regarding fetal well-being.