Although
prostaglandins (PGs) are considered the key mediators of human parturition at term, there is a paucity of data regarding their participation in the mechanisms responsible for
preterm labor. The purpose of this study was to establish if
preterm labor is associated with changes in the amniotic fluid concentrations of
prostaglandins.
PGF2 alpha, 13,14-dihydro-15-keto-prostaglandin F2 alpha (
PGFM) and 11-deoxy-13,14-dihydro-15-keto-11,16-cyclo-prostaglandin E2 (PGEM-ll) were measured by using specific and sensitive radioimmunoassays. Amniotic fluid was retrieved by transabdominal amniocentesis from 55 women with
preterm labor and intact membranes. Patients were divided into three groups according to the response to
tocolysis and the presence or absence of an intra-amniotic
infection. Amniotic fluid concentrations of
PGFM and PGEM-ll were significantly greater in women with
preterm labor and intra-amniotic
infection than in women without
infection. In addition, patients unresponsive to
tocolysis without intra-amniotic
infection also had a significantly greater concentration of
PGFM and PGEM-ll in amniotic fluid than those responsive to
tocolysis. Amniotic fluid concentrations of
PGF2 alpha were greater in women with intra-amniotic
infection than in women without intra-amniotic
infection. In the absence of intra-amniotic
infection, no difference in amniotic fluid
PGF2 alpha concentrations could be found between women who responded to
tocolytic treatment and those who did not.