Abstract
With the increase in our knowledge of the role played by the pituitary and ovarian hormones, attention is being directed toward the possibility of a hormonal source as a fundamental cause which induces labor. Animal experiments suggest that there is a synergistic action between oestrin and pituitrin. If the isolated uterus is first bathed with oestrin, it becomes more sensitive to pituitrin as manifested by increase of contraction.1-5 On this hypothesis, a hormonal theory as to the cause of the onset of labor may be summarized as follows: During early pregnancy oestrin is held in abeyance by the presence of the luteinizing factor in the ovary, placenta, and anterior hypophysis, and as maturity of gestation approaches release of this inhibiting action upon oestrin is observed. The uterine sensitivity to pituitrin, stimulated by the released oestrin, becomes more marked and continues until the threshold is reached, when labor is precipitated.
To test this theory clinically, a series of hormonal injections was undertaken on 45 pregnant negro women at term. The ovarian follicular hormone, in the form of theelin, was administered in various dosages, singularly and daily, to 10 pregnant women who were at term. Labor occurred within 36 hours in only 2 cases. Ovarian follicular fluid, aspirated at operation, was given to 2 women in a similar state; neither delivered in the allotted time. This same hormone in the form of amniotin or progynon was administered alone, or in combination with pituitrin or pitocin, the active uterine stimulating principle of pituitrin, in various dosages and at differentintervals, to 30 full term pregnant negro women. Seven delivered within 36 hours.
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