Gestational age-specific reference values of placental thickness in normal pregnant women

ABSTRACT

The aim of this study was to determine the reference values of the placental thickness in 400 normal pregnant women during weeks 16–41 of gestation who were referred to the Mahdiyeh hospital during January 2014–February 2015. The placental thickness at the junction of the umbilical artery was measured using ultrasonography. Multivariable linear regression was used to model the mean placental thickness and assess associations with measured covariates, including gestational age (GA). Centiles for placental thickness distribution were estimated according to the modulus exponential–normal model. The mean and standard deviation of the age of the participants was 31.4 ± 5.7 years. The Pearson correlation coefficient indicated a very strong positive linear correlation between GA and placental thickness (p <.001; r = 0.93). A nonlinear increase of placental thickness with estimated fetal weights was observed. GA-specific placental thicknesses for the 2.5th, 5th, 10th, 25th, 50th, 75th, 90th, 95th, and 97.5th percentiles of placental thickness were calculated. By making use of the provided nomogram in this study, neonatal outcomes associated with the placental thickness, such as Hemoglobin Bart’s disease, can be diagnosed early to improve maternal and newborn health.

KEYWORDS:

• Estimated fetal weight
• gestational age-specific
• placental thickness
• reference values

Authors’ contributions

KE, MM, AB, and BS designed the project. BM and MH wrote the manuscript. MH, MZ, and BM contributed to concept, drafting, analysis, and interpretation of data. All authors collected data. BM conducted data and statistical analysis. All authors read and approved the final version.

Ethical approval

The proposal of this research has been approved in the Ethics Committee of Shahid Beheshti University of Medical Sciences.

Informed consent

All the individuals had been informed of the purposes of the study and gave their informed consent.

Declaration of interest

The authors have stated explicitly that there are no conflicts of interest in connection with this article.