Control of Parturition in Man

Prostaglandins during pregnancy and the perinatal period

“…Chorion, decidua and placenta all produce PGs although only the rate of production of 6-keto-PGF-la by amnion is significantly greater after labour ( (Williams, El-Tahir & Marcinkiewicz, 1979) and perhaps a similar action in women may provide a role for prostacyclin in the mechanism of labour. Certainly the high rates of production of prostanoids by amnion are consistent with the suggestion that the trigger for the onset of human labour may reside in the fetal membranes and be prostaglandin in nature (Liggins, Forster, Grieves & Schwartz, 1977). .…”

Hormonal changes around the parturition in rats.

“…Csapo et al (1973) emphasized the role of progesterone as the inhibitory agent to the onset of labor. Liggins et al (1977) reported that labor in human pregnancy might be initiated by a signal arising in the fetal membrane. As stated above, the hypothesis on initiation of labor is still much confusing, and further investigation should be necessary.…”

Distribution of arachidonic acid and other fatty acids in the lipids of guinea-pig uterus and plasma in relation to uterine prostaglandin synthesis

“…In women, there is evidence of lysosome-mediated release of phospholipases into the amniotic fluid during parturition (Gustavii, 1972;Liggins, Foster, Grieves & Schwatz, 1977), suggesting that phospholipids represent a source of arachidonic acid for PG synthesis. Triglyceride-rich lipid droplets, which accumulate in the uterus during dioestrus and pregnancy in animals of several species, and which are depleted at oestrus (Beali, 1972), have also been suggested as an arachidonic acid source (Brinsfield & Hawk, 1973;Thorburn & Challis, 1979).…”