Early amniocentesis: effect of removing a reduced volume of amniotic fluid on pregnancy outcome

In mid-trimester amniocentesis (MTA), 12-15 ml of amniotic fluid is aspirated for cytogenetic analysis. When a similar volume of amniotic fluid is removed by early amniocentesis (EA), it represents a significant proportion of the total amniotic fluid volume in the first trimester. The fluid depletion, which may persist for 7 to 10 days, is considered to impair development of fetal lungs and extremities and, possibly, contribute towards procedure-related congenital abnormalities and miscarriages. By only removing 7 ml of amniotic fluid, we have demonstrated a total miscarriage rate (3.8 per cent) comparable with previous large studies (Table V), a low incidence of respiratory difficulties at birth (2.7 per cent) and a low incidence of fixed flexion deformities (1.6 per cent), at the expense of a small increase in the incidence of culture failure (2.2 per cent).