Assessment of fetal lung maturity by amniocentesis with the lecithin/sphingomyelin ratio

Abstract

F,a administered intravenously, intra-amniotical-’ ly, or intravaginally. Fetal skin from 31 abortuses induced by prostaglandin F,a and from 10 abortuses induced by hypertonic saline have been cultured to determine their suitability for biochemical and cytogenetic study. The specimens were obtained from the buttock of an abortus at the completion of abortion and kept refrigerated until the following day, if not taken care of immediately. The skin and underlying tissues were minced and implanted in culture medium (minimum essential medium with 20 per cent fetal calf serum and antibiotics) and placed in a CO2 incubator. None of the 10 specimens from the hypertonic saline injection group grew. They became grossly contaminated within 3 to 4 days or failed to exhibit signs of growth after 3 or 4 weeks even if not contaminated. About two thirds of the specimens from the prostaglandin group grew as vigorously as does fetal skin obtained from hysterotomy specimens and were usable for various studies. The somewhat less than 100 per cent success rate in the prostaglandin group may have been due to less than ideal handling of specimens during abortion, such as the expulsion of a fetus on a clean but nonsterile sheet. The high failure rate in the 12 to 24 hour group is not readily explainable (Table I) . The mechanism by which prostaglandin F+Y induces abortion apparently does not cause immediate death of the cells of the fetal skin as does hypertonic saline. At least under the conditions of the study, skin fibroblasts were quite culturable from fetuses expelled after prostaglandin F,a induction of abortion, even in the absence of any special precautions to assure success. Extra care to prevent contamination in handling the fetus would probably have given a higher yield of successful cultures. Whenever it is desirable to culture fetal tissue after abortion, the induction of abortion by prostaglandin FZ~ is preferred over hypertonic saline.