Freshly prepared aqueous decocts of the Mexican plant Montanoa tomentosa (Zoapatle) were administered orally to six women in the early stages of pregnancy for two days prior to the interruption of gestation by vacuum aspiration. The daily dose administered varied between 1.0 and 1.4 gm-equivalent of dry leaves per kilogram of body weight. A comparable control group of six pregnant women received the same volume of commercial tea according to the same schedule before vacuum aspiration. Administration of Zoapatle extracts resulted in a menstrual-like cramp and a significant dilatation of the cervix in all subjects studied. In four of the six subjects the menstrual-like pains were associated with bleeding. No comparable effects were observed in the control group. Peroral administration of Zoapatle decocts did not produce any cardiovascular changes, and it did not influence the hematologic status, liver, kidney, and thyroid function, blood lipids, proteins, and electrolyte status. Under the experimental conditions used, Zoapatle extracts did not induce a luteolytic effect judged from the plasma progesterone (and estradiol) levels. It is concluded that peroral administration of freshly prepared decocts of Zoapatle in early pregnancy exerts a distinct uterotonic effect and induces cervical dilatation and uterine bleeding. These changes are not associated with any effect on the plasma levels of progesterone and estradiol or with any untoward side effects. © 1979.
