This research earliest quantified the fresh discrepancy ranging from LMP and you will USG-founded (Hadlock) relationships tips from inside the earliest trimester in an enthusiastic Indian people. We characterised how for each and every method you’ll subscribe the discrepancy in the calculating the fresh GA. I next dependent a society-specific model regarding GARBH-Ini cohort (Interdisciplinary Class for Advanced Lookup towards the Birth consequences – DBT Asia Step), Garbhini-GA1, and you may compared the efficiency towards had written ‘large quality’ formulae to the earliest-trimester relationship – McLennan and Schluter , Robinson and you will Fleming , Sahota and you can Verburg , INTERGROWTH-21 st , and you will Hadlock’s algorithm (Dining table S1).