Plasma concentrations of prostaglandins during late human pregnancy: Influence of normal and preterm labor

Highly sensitive and specific RIA procedures have been used to measure prostaglandin concentrations in the peripheral circulation of late pregnant and parturient women. The concentrations of prostaglandin E (PGE) and prostaglandin F (PGF) in plasma samples assayed within 4 weeks of collection were not significantly different among the groups studied, the levels (mean ± SEM, picograms per ml) were: late pregnancy (n = 13): PGE, 4.8 ± 1.0; PGF, 6.2 ± 0.5; early term labor (n = 5): PGE, 6.8 ± 1.5; PGF, 7.9 ± 0.7; late term labor (n = 5): PGE, 5.4 ± 2.2; PGF, 12.4 ± 3.5; and preterm labor (n = 7): PGE, 4.4 ± 0.4; PGF, 6.9 ± 1.4. The concentration of 13,14-dihydro-15-keto-prostaglandin F (PGFM) in late pregnancy was 59.0 ± 7.8 pg/ml. During spontaneous term labor, the concentration of PGFM was significantly elevated (P < 0.01) to 142.8 ± 32.3 pg/ml in early labor and 282.7 ± 55.3 pg/ml in late labor. The concentration of PGFM in plasma from patients in preterm labor (62.7 ± 17.4 pg/ml) was not significantly different from that found during late pregnancy, but was significantly lower than levels found at term during early labor (