Assessment of fetal maturity in Nigeria by amniotic fluid analysis.

Seven different tests of amniotic fluid have been evaluated for assessment of gestational age. Statistical correlation of the lecithin/sphingomyelin (L/S) ratio with gestational age was positive and significant (P less than 0.001). The Nile blue hydrochloride staining test was very reliable in predicting fetal maturity: in all cases where there was at least 15% of orange-staining cells, the age of the fetus was 37 weeks or more. The reliability of this test was greatly improved when combined with the amniotic fluid L/S ratio, and the result of Clements' "shake test", especially when the creatinine value was also greater than 176 mumol/1. Changes in the levels of amniotic fluid urea, uric acid and total protein were not sufficiently consistent to be of value in assessing fetal maturity. Where facilities for ultrasound are not available, these simple tests can be very helpful in the determination of fetal maturity and in the prevention of accidental delivery of immature fetuses.