Evaluation of a low-dose progestagen as a contraceptive
Iizuka, R.; Hayashi, M.; Kamouchi, Y.; Yamanaka, K.
Nihon Funin Gakkai Zasshi 16(1): 68-82
1971
ISSN/ISBN: 0029-0629 PMID: 12158578 Document Number: 482563
In order to evaluate the safety and effectiveness of a low-dose progestagen oral contraceptive, 46 women were administered 0.25 mg daily of a synthetic gestagen, R-2453 (17alpha-methyl delta 9-19 norprogesterone) for 1-12 months for a total of 189 cycles. The pill was found to be safe and completely effective with no pregnancies occurring in the study group. The length of the bleeding cycle was found to be prolonged under this treatment, to an average of 40 days . Bleeding duration and amount were generally the same as those before treatment, except in 3 cases where irregular bleeding prompted discontinuance of the pill use. Basal body temperature patterns were measured and found to be atypical biphasic in 17.3% of the cases, high temperature monophasic in 47.2%, and irregular in 34.6%. Routine blood, kidney and liver function tests were normal. Pregnandiol excretion before withdrawal bleeding was low in all but 1 case. Cervical mucus was also low and no crystal formation was observed. In the nidation menstrual stage the endometrial glands were few in number and adenomeres were small in size. In glandular cells, supranuclear vacuoles were found and interstices were coarse and edematous. Histological examinations in the implantation phase showed some alterations but their relationship to the contraceptive mechanism of this pill is not clear. Low-dose progestagens appear to be highly effective contraceptive agents that do not suppress ovulatory activity but their prescription must take careful note of dosage and formulas.