Ultrasonographic assessment of gestational age with the distal femoral and proximal tibialepiphyseal ossification centers in the third trimester

Abstract

Background: Pregnant women are frequently unsure of their last menstrual period. When this is combined with late booking for antenatal care, gestational age determination becomes a real challenge. Study was conducted to ascertain the predictive values of the distal femoral and proximal tibial epiphyseal ossification centre measurements in estimating pregnancy in the third trimester. Methods: An observational cohort study using women with singleton pregnancies (30–40 wks) attending antenatal clinic in Jos University Teaching Hospital. The distal femoral and proximal tibial epiphyseal ossification centers were identified and measured by ultrasonography. Monogram of foetal bone development was employed also considering the diameters of the two centers. Results: Gestational age correlated well with the diameters of the distal femoral and the proximal tibial epiphyseal ossification centers. The presence of the distal femoral and proximal tibial epiphyseal ossification centre had a positive predictive values of 94.3% (n, 106) and 98.7% (n, 136) respectively. Conclusion: Ultrasonographic measurement of the diameters of the distal femoral and proximal tibial epiphyseal ossification centers may be useful in the estimation of gestational age during the third trimester.