Accurate gestational age estimation is crucial for managing maternal and neonatal health outcomes. In low-resource settings like Sudan, the last menstrual period (LMP) and ultrasound are common methods for estimating gestational age, but studies comparing their accuracy in Sub-Saharan Africa, particularly in Sudan, are limited. This cross-sectional study, conducted in Gadarif Maternity Hospital from November to December 2022, evaluated the correlation between LMP and ultrasound-based gestational age estimates among 476 pregnant women. Sociodemographic data, including participants’ age and gravidity, were collected, and LMP dates recorded. Ultrasound measurements using a 3.5-MHz convex sector probe assessed gestational age by measuring crown-rump length in early pregnancy and biparietal diameter and femur length in later stages.
Results indicated a strong positive correlation between LMP and ultrasound gestational age estimates (r = 0.921, P < 0.001). However, LMP-based estimates averaged slightly higher than ultrasound estimates, with a mean difference of 0.01 weeks (95% CI: -0.05 to 0.07). Bland-Altman analysis revealed limits of agreement ranging from -1.36 to 1.38 weeks, indicating potential variability between the two methods. Linear regression analysis suggested a proportional bias, with the mean difference coefficient at 0.26 (95% CI: 0.01 to 0.03, P < 0.001). These findings highlight a bias in LMP-based estimations compared to the more consistent ultrasound method, suggesting that reliance solely on LMP in low-resource settings may lead to gestational age miscalculations.
In conclusion, LMP-based gestational age estimation may be less reliable than ultrasound in Sudan’s late antenatal care context, underscoring the importance of integrating ultrasound where possible to enhance prenatal care accuracy.
