The diagnostic criteria for low amniotic fluid are divided into two areas.
Clinical manifestations: reduction in uterine size and fetal movement; vaginal fluid flow in cases of premature rupture of membranes; examination of abdominal circumference and uterine height smaller than in the same pregnancy; easy to induce contractions by slight stimulation, intense post-partum paroxysms, more uncoordinated contractions, slow dilatation of the uterine opening and prolonged labour.
Auxiliary examination: B-type ultrasound, maximum amniotic fluid level ≤2cm is considered as low amniotic fluid; ≤1cm is considered as severe amniotic fluid. Amniotic fluid index method ≤5.0cm as hypohydramnios. Direct amniotic fluid measurement: after rupture of membranes, amniotic fluid is measured directly; less than 300ml is considered too little amniotic fluid.