我睇雜誌好似有2種唐氏綜合症檢查都係驗血.testing on 11-14wks have accuracy of 90% (plus Ultra sound), need 1 hr to generate report, while another testing could be done around 15-16wks, having an accruacy rate of 70% only and need 1wk to get the report. Make sure you don't get confused.
Normal weight gain for the whole 40wks would be around 12-17kg, i.e.26-37lb. Ideally the first trimester would gain around 2-3 kg and remaining 28 weeks would gain 0.5kg (1lb) per week. Of course this is only for reference only. But make sure do not attempt to be on diet has this will be of no good to your baby!!
In my case, I am 13wk+1 but still get no weight gain, though nurse/doctor said my baby is of normal size.