Statistical Analysis
The sample size was calculated based on a stillbirth rate in Delhi (2.9%) obtained from an earlier study. Presuming that through ultrasound ,the stillbirth rate can be reduced by 30% a sample size of 2700 would have statistical significance with 80% power at a 5% level of significance. We analysed the data in the study cohort according to the defined subcategories of FGR, SGA and AGA. Next, we compared the outcome variables of study cohort to official data submitted to Delhi government over the same duration using STATA software version 12.0(2011) Continuous variables were tested for normality assumption using Kolmogorov-Smirnov test. We calculated descriptive statistics for normally distributed data and compared the mean values using (ANOVA)/Student’s t-independent test, as appropriate. We presented categorical variables as frequency and percent values and compared using Chi-square/Fishers exact test. Unadjusted risk ratio and 95% confidence limits were calculated to identify risk variables for various outcomes. For all statistical tests, a two-sided probability of P<0.05 was considered for statistical significance.