Birth weight estimation--a sonographic model for Pakistani population.

OBJECTIVE To develop a sonographic birth weight estimation model for Pakistani population and to validate the published models in the same population. METHODS Data was collected for pregnant women who presented to Radiology Department of Aga Khan University Hospital Karachi from January 2007 to July 2008 and had undergone ultrasound estimation of foetal weight within 4 days prior to a term delivery (37-42 weeks gestation). The neonate's actual birth weight was used to validate the published foetal weight estimation models and modified sonographic birth weight estimation model was derived for our population by using linear regression. RESULTS Modified sonographic birth weight estimation model for our population was derived by using foetal parameters. No significant difference (p-value > 0.05) of actual and predicted birth weight derived from Our regression model, Campbell and Woo models was noted, however least difference (p = 0.7) was identified between our predicted model (Mean difference 14 +/- 37.7 g). CONCLUSION Our sonographic modified regression model of foetal weight estimation gave the least difference with actual neonatal birth weight and can be reliably used in our population. Hadlock1, Hadlock2 and Woo2 models are not appropriate in our setting or should be used carefully while predicting foetal weight in our population.