Background: Accurate assessment of gestational age at birth is critical to the identification of neonates at high risk. In resource-poor settings, postnatal techniques are commonly used but may be difficult to apply and have not been well validated against ultrasound in community studies. The aim of this study was to evaluate postnatal assessment of gestational age in rural Africa using the external criteria of the Ballard examination against 1st/early 2nd-trimester ultrasound and date of last menstrual period.
Method: In a sample of women from Kiang West, The Gambia (n=80), the precision of gestational age estimates using the external Ballard examination was compared with those derived from 1st and early 2nd-trimester ultrasound examination and date of last menstrual period.
Results: The incidence of preterm delivery was low at 2.5%. The external Ballard examination tended to underestimate gestational age by a mean (SD) of 15.6 (10.9) days compared with that derived from ultrasound and to underestimate by 15.4 (23.1) days compared with that derived from date of last menstrual period. The differences between the methods varied with gestation.
Conclusion: In this rural, community-born population of infants, postnatal assessment of gestational age by external Ballard examination performed poorly compared with ultrasound and last menstrual period. No reliable gestational age could be derived from its estimate and it failed to detect a significant proportion of high-risk infants. The development of an accurate but simple method of postnatally assessing gestational age specifically for use by health workers in rural Africa is required.