15-keto-13-14-dihydroprostaglandin-f2alpha and Fetal-Membranes--Premature-Rupture

Rupture of membranes at term, whether spontaneous or artificial, causes rapid and sustained increase in prostaglandin F2 alpha (PGF2 alpha) metabolite (PGFM) levels and is associated with augmentation of uterine contractions. To investigate why premature rupture of membranes (PROM) often fails to initiate uterine contractions, we measured plasma concentrations of PGFM and oxytocin (OT) in patients with PROM near term. Serial blood samples were taken before and after PROM as well as before and after local PGE2 gel application for cervical ripening. For comparison, patients with similar criteria with intact membranes were also studied, as were patients in spontaneous labor at term with and without spontaneous rupture of membranes. PROM was always associated with an initial, marked increase in plasma PGFM. Whether or not this increased PGF2 alpha production was maintained was related to the cervical status at the time of PROM. In patients with unripe cervix PGFM levels returned to initial levels within 2 hours and no contractions were elicited; when the cervix was 3 cm or more dilated, PGFM levels remained high and contractions began within 1 to 3 hours. PROM had no significant effect on plasma OT levels. When PGE2 gel was applied to ripen the cervix, PGFM levels increased moderately within 30 minutes in all patients regardless of the status of the membranes. In patients with intact membranes the concentration of PGFM in plasma declined to initial levels within 4 hours, whereas in patients with PROM, PGFM levels remained increased throughout the study period.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Adult; Cervix Uteri; Dinoprost; Dinoprostone; Female; Fetal Membranes, Premature Rupture; Humans; Labor Onset; Labor, Obstetric; Oxytocin; Pregnancy; Uterine Contraction

Premature rupture (= PR) of the amnion is a serious complication even for the mature child if it occurs earlier than 24 hours before birth. To keep the interval as short as possible, the authors induce labour from week 35/0 in case of PR, provided the Bishop score is greater than 7. If the bishop score is lower, they conduct intracervical priming of the cervix with 0.4 mg PGE2 gel before induction of labour. This has proved clinically superior to intravenous procedures. In the study presented here, the authors attempted to find out whether intracervical administration of PGE2 gel would result in changes in the maternal and foetal plasma concentrations of oxytocin, PGFM, or PGEM when comparing conditions in case of ruptured amnion with those if the amnion remained intact. If the amnion is intact and the cervix immature (less than 2 cm), intracervical administration of 0.4 mg PGE2 gel produces a significant OT increase within 30 minutes. From a cervical width of 2 cm onwards, the OT levels are already primarily enhanced and will hardly change even after PGE2 gel administration. Similar conditions obtain in PR. PGFM plasma levels will rise only slightly within an hour after intracervical PGE2 gel administration, independent of whether there has been a rupture or not, or whether the cervix is dilated less than 2 cm or 2 cm and more.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Administration, Topical; Cervix Uteri; Dinoprost; Dinoprostone; Female; Fetal Membranes, Premature Rupture; Humans; Maternal-Fetal Exchange; Oxytocin; Pregnancy; Prostaglandins E; Prostaglandins F

The plasma concentrations of oxytocin and 13,14-dihydro-15-keto-prostaglandin F2 alpha (PGFM) were measured in serial samples collected during the first stage of spontaneous and oxytocin-induced labor in 17 and 15 women, respectively. Four women in late pregnancy served as control subjects, with serial samples collected at similar intervals as during labor. During spontaneous labor, mean plasma oxytocin levels were consistently raised over the levels observed 1 to 2 weeks before the onset of labor and were higher than the levels in the control patients (mean, 19.9 +/- 3.1 pg/ml) and the initial levels in the oxytocin-induced group of women (mean, 17.4 +/- 4.8 pg/ml). The mean plasma oxytocin levels during spontaneous labor (45 +/- 3.9 pg/ml) were similar to those observed during infusion of 4 to 6 mU/min of synthetic oxytocin (49.1 +/- 10.9 pg/ml). Plasma oxytocin levels increased progressively with stepwise increments of the infusion. Plasma PGFM levels also rose during labor, but, in contrast to the oxytocin levels which increased in early labor, plasma PGFM levels did not increase significantly until relatively late in labor, provided the membranes were intact. The state of the membranes had a marked influence on plasma PGFM; patients with spontaneous rupture of membranes had significantly increased PGFM levels when admitted early in labor or when membranes ruptured during labor. This increase in prostaglandin F2 alpha (PGF2 alpha) production does not by itself suffice to initiate labor, as evidenced by the failure of premature rupture of the membranes to initiate labor in a number of patients with elevated PGFM levels in whom labor was then induced with oxytocin. Conversely, oxytocin induction was successful only when PGFM levels increased during the infusion of oxytocin; in the absence of a rise in plasma PGFM, oxytocin induction failed. These data add support to the view that both oxytocin and PGF2 alpha are required for adequate stimulation of the human uterus during labor. In addition, the data suggest that oxytocin rather than PGF2 alpha may be the major stimulus that initiates labor, whereas PGF2 alpha appears responsible for the progress of labor.

Topics: Cervix Uteri; Dinoprost; Extraembryonic Membranes; Female; Fetal Membranes, Premature Rupture; Humans; Infusions, Parenteral; Labor, Induced; Labor, Obstetric; Oxytocin; Pregnancy; Prostaglandins F; Time Factors