Anatomy General obstetrics 9ea6f002 The major contribution of amniotic fluid after 20 weeks of gestation : A Ultrafiltrate and maternal plasma B Fetal urine C Fetal lung fluid D Fetal skin High-Yield Explanation Origin of amniotic fluid : Early week -Maternal plasma 2 nd trimester - Fetal skin Beyond 20 weeks -Fetal urine Ref: Datta Obs 9e pg 34.