Evaluation of gestational age by fetal occipitofrontal diameter in second and third trimesters of pregnancy in Sudanese women

Background and Objective: The accurate gestational age (GA) is critically important for pregnancy management, particularly for determining viability and growth in premature labor. The aim of this study was to evaluate the usefulness of occipitofrontal diameter (OFD) in estimation of GA in the second and third trimester of pregnancy.Materials and Methods: In this cross‑sectional prospective study, a total of 483 Sudanese pregnant women underwent the routine sonographic examination at different antenatal care centers in Khartoum state using curvilinear transducers 3.5 MHz. The fetal OFD, biparietal diameter (BPD), and femoral length (FL) were measured and correlated with GA. Equations were obtained from regression models to estimate the GA.Results: In total, 384 singleton fetuses ranging between 12 and 40 weeks of gestation were enrolled. A statistically significant and strong relationship was found between OFD and GA, R2 = 0.85. The model regression of OFD, BPD, and FL produced together with an accurate equation to estimate GA in second and third trimester with the equation; GA (weeks) = 4.474 + 100 × BPD + 0.118 × OFD + 0.128 FL (r = 0.909, n = 384, SE = 2.271). The equation of GA from OFD alone was GA = 3.663+.286 × OFD with SE = 2.882. The OFD can be used as a single lone parameter in the estimation of GA to give an accuracy of SE ± 2.882 days, but when used in combination with the other two parameters, the accuracy increased to SE ± 2.770 days.Conclusion: Fetal OFD assessed by sonography may serve as a useful parameter in determining GA and evaluating fetal growth in the second and third trimesters of pregnancy.Keywords: Gestational age; occipital‑frontal diameter; pregnancy; Sudanes