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Related Experiment Video

Updated: Apr 28, 2026

High Frequency Ultrasound for the Analysis of Fetal and Placental Development In Vivo

High Frequency Ultrasound for the Analysis of Fetal and Placental Development In Vivo

Published on: November 8, 2018

Population-based placental weight ratio distributions.

Erin M Macdonald¹, John J Koval², Renato Natale³

¹Department of Epidemiology and Biostatistics, The University of Western Ontario, London, ON, Canada N6A 5C1 ; Department of Obstetrics and Gynecology, The University of Western Ontario, London, ON, Canada N6A 5C1 ; Children Health Research Institute, London, ON, Canada N6C 2V5.

International Journal of Pediatrics

|June 5, 2014

Summary

The placental weight ratio (PWR) indicates fetal and placental growth balance. This study established PWR standards by gestational age and found it differs significantly for small (SGA) and large (LGA) for gestational age infants.

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Area of Science:

Obstetrics and Gynecology
Perinatology
Fetal Development

Background:

The placental weight ratio (PWR) is a key indicator of fetal and placental growth balance.
Established ranges for PWR across gestation and by fetal growth adequacy are currently lacking.
Understanding PWR variations is crucial for assessing fetal well-being.

Purpose of the Study:

To establish population-based reference ranges for the placental weight ratio (PWR) stratified by gestational age.
To investigate the association between PWR distributions and fetal growth adequacy (SGA, AGA, LGA).

Main Methods:

Retrospective cohort study of 41,441 live singleton births from two hospitals in London, Ontario (over 10 years).
Inclusion criteria: gestational age 22-42 weeks.
Nonparametric quantile regression was utilized to model PWR distributions.

Main Results:

PWR and its dispersion decrease with increasing gestational age.
Infants small for gestational age (SGA) exhibited a higher proportion of extreme PWRs compared to average (AGA) and large (LGA) for gestational age infants, particularly at earlier gestations.
On average, SGA infants demonstrated higher PWRs than AGA and LGA infants.

Conclusions:

The study provides the first population-based reference curves for PWR stratified by fetal growth adequacy.
These findings highlight significant differences in PWR between SGA, AGA, and LGA infants.
The established curves serve as valuable population standards for research and clinical applications in fetal growth assessment.