Assessing gestational age of babies: Performance of obstetric ultrasound scan compared to that from the combination of Naegle’s rule and Dubowitz score in the 21st century

Background: Some researchers have suggested that when Naegle’s rule (NR) and Dubowitz score (DS) are combined, it could out-perform obstetric ultrasound scan (USS). Others still believe that obstetric USS alone is still effective relative to the combination of NR rule and DS in assessing the gestational age (GA) of babies. Objectives: To determine and compare the GA of babies using obstetric USS, NR and DS; and to provide relevant public health information on obstetric USS in the 21st century. Methods: Subjects were selected using systematic random sampling and the GA of babies was determined using obstetric USS, NR, and DS. Statistical package for social science (SPSS) statistical software version 16, Illinois, Chicago USA was used for all data analysis. Results: Eightyfive mother-baby pairs were studied. Forty-four babies (52%) were males and 41 (48%) females. Sixty four (75%) were term with a mean (SD) BW of 3.02 (0.59) at 95%CI (2.89 3.14) kg. The overall mean GA of the babies was 38.49 (2.89) at 95%CI (38.14 38.85) weeks. The mean GA using obstetric USS, NR and DS were 38.52 (1.98) at 95%CI (38.14 38.99), 38.09 (4.13) at 95%CI (37.20 38.99) and 38.82 (2.02) at 95%CI (38.39 39.26), but comparison of these means was not significant (p = 0.256). Combined mean GA by NR and DS was 38.46 (3.26) at 95%CI (37.96 38.95). Comparing this mean with mean GA obtained by obstetric USS was also not significant (p = 0.885). Conclusion: The GA assessments by Obstetric USS, NR and DS were all reliable, and Obstetric USS performed effectively relative to combined NR and DS.