Initiation of human parturition. I. Mechanism of action of arachidonic acid

P. C. MacDonald, F. M. Schultz, J. H. Duenhoelter, N. F. Gant, J. M. Jimenez, J. A. Pritchard, J. C. Porter, J. M. Johnston

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Free fatty acid levels were determined in amnionic fluid from women in labor and from women not in labor. Of these fatty acids, the most striking increase occurred in the concentration of arachidonic acid. Prostaglandin F(2α) was also increased in amnionic fluid from women in labor. Twelve women requesting abortion during the second trimester had arachidonate, the precursor of prostaglandin PGF(2α) injected into the amnionic sac. All 12 women aborted. Two additional patients, who were injected with arachidonate, ingested aspirin, and they did not abort. Two women were injected with oleate, and they also did not abort. Indeed, in these latter 4 patients, no uterine contractions, cervical dilation, or effacement was observed. Four women whose fetuses died in utero during the third trimester were given arachidonate intraamnionically Each commenced labor and promptly delivered. On the basis of these observations, arachidonate injection as a mechanism for the initiation of labor in humans is proposed.

Original languageEnglish (US)
Pages (from-to)629-636
Number of pages8
JournalObstetrics and Gynecology
Issue number5
Publication statusPublished - 1974


ASJC Scopus subject areas

  • Obstetrics and Gynecology

Cite this

MacDonald, P. C., Schultz, F. M., Duenhoelter, J. H., Gant, N. F., Jimenez, J. M., Pritchard, J. A., ... Johnston, J. M. (1974). Initiation of human parturition. I. Mechanism of action of arachidonic acid. Obstetrics and Gynecology, 44(5), 629-636.