[The amniotic fluid volume in uncomplicated singleton pregnancies: the ultrasonic study technics]

In 750 uncomplicated singleton pregnancies, 1765 examinations have performed to establish the normograms for 4 Ultrasound techniques of measurement of amniotic fluid volume (AFV). The 90% and 95% and 98% confidence intervals for each method across gestation (16-43 weeks) were calculated from polynomial regression equation for 50th percentile from logarithmic transformed data, and antilog values were plotted in graphical representation for modified amniotic fluid Index (MAFI). The variations of the mean values of data between weeks were statistically significant (p < 0.00001). Normograms show the progressive increase of AFV up to 27-29 weeks (27-32 weeks plateau), then declined to term. In postdate period the decrease of AFV was 7%-10% weekly for MAFI. In term gestation, the mean AFV of 5th and 95th percentile that defines the lower and upper limits were 6.7 & 21.3 cm for MAFI, 6.2 & 19.9 cm for AFI (amniotic fluid index), and for maximum vertical single pocket (MVP)--2.5 & 7.4 cm and for two-diameter pocket (TDP)--10.4 & 51.0 c2.