Indian Journal of Obstetrics and Gynecology Research

Gestational age determination by ultrasonic placental thickness measurement

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Author Details: Maya Menon, Vinodha M

Volume : 3

Issue : 3

Online ISSN : 2394-2754

Print ISSN : 2394-2746

Article First Page : 279

Article End Page : 282


Introduction: Gestational age is frequently estimated based on last menstrual period and on ultrasonography. Many people are unaware of their last menstrual period due to irregular menstruation and ultrasonography is bound to have a bias, thereby posing difficulties in the estimation of gestational age. Placenta is a fetal organ which provides the physiological link between pregnant women and her fetus. Placental growth can be estimated by measuring the thickness and estimating its volume. Placental thickness is directly related to the gestational age of the fetus till certain weeks of pregnancy.
Objectives: To study the correlation between ultrasonographic placental thickness and gestational age of the fetus.
Methods: This is an observational study done at ESIC Medical College & PGIMSR Chennai. 333 cases were recruited for the present study to determine the normal placental thickness for various gestational age and to study the correlation between ultrasonographic measurement of placental thickness and gestational age of the fetus.
Results: Placental thickness for gestational age 11-40 weeks calculated, it gradually increased from 14.6 mm at 11weeks to 38.9mm at 40 weeks gestation. Correlation coefficient is 0.98 and p value <0.0001.There is a significant positive correlation of placental thickness with other fetal biometry parameters like BPD, FL, AC, HC and CRL.(p < 0.0001) for BPD, FL, AC and HC and (p=0.02) for CRL.
Discussion: There appears to be a linear relationship between gestational age and placental thickness. Thus, placental thickness can be reliably used to estimate gestational age importantly for mothers whose clinical history is not reliable, who come for antenatal booking in second half of pregnancy and in conditions where BPD measurements becomes less reliable.

Placental thickness, Gestational age, Ultrasonography, Fetal biometry