Nakaka-confusing talaga yan, lalo na pag may conflicting dates na agad! Based sa experience ko, irregular periods talaga ang culprit, yung dating calculation mo from your last period ay iba na compared sa what the ultrasounds are showing, kaya yan yung gap between August at September. The good thing is your OB is being thorough by asking you to repeat the BPS ultrasound, at yep, the OB-sonologist should be able to clarify better kung talagang malaki lang si baby or kung medyo off talaga ang dating, they can measure more accurately at that point, especially kung may karagdagang growth from the previous scans. Honestly, best to just go through with the repeat at communicate clearly sa sonologist about your irregular periods so they have the full picture. Once you do, magiging clearer na kung san tayo talaga!