Determination of Fetal Gestational Age in Singleton Pregnancies: Accuracy of Ultrasonographic Placenta Thickness and Volume at a Nigerian Tertiary Hospital

Abstract

To determine the accuracy of placenta thickness and volume in the correct determination of gestational age among normal
singleton pregnancies in Nigerians. In this perspective cross-sectional study, four hundred and twenty-three (423) consenting
healthy singleton pregnant women within 13-40weeks gestational age (GA) with regular menstrual cycle and known last
menstrual period were recruited and grouped into 27 groups based on their ultrasound GA. All participants had an obstetric
ultrasound, and the main outcome variables were placenta thickness, placenta volume, and ultrasound GA. The data generated
were analyzed, and P values ≤ 0.05 were statistically significant in this study. Four hundred and eight (408) normal singleton
pregnant women with an average age of 29.6(+/-5) years completed the study. One hundred and seventy-seven (43.4%) were
between 26-30 years, while 149(36.5%) were aged 31 years and above. The placenta thickness showed a strong positive linear
relationship between GA (Y-axis) and placenta thickness (in mm) (x-axis) with a best-fit line of Y -= -0.19 + 1x. The placenta
volume values (X) also had a positive but non-linear. There is a linear relationship between placenta thickness and GA and
curvilinear relationships between placenta volume and GA. Routine assessment of placenta thickness and volume could serve as
an effective alternative means of dating normal pregnancy in women with unreliable dates of the last menstrual period.