Abstract
Background: Administration of low doses of an antiprogestin to rhesus monkeys permits ovarian/menstrual cyclicity, suppresses endomaterial proliferation and prevents pregnancy without adverse or toxic side-effects after 5-6 months of daily treatment. The purpose of this study was to test reversibility with respect to restoration of fertility after 1 year of low-dose antiprogestin treatment. Methods: This experiment included a daily 1 year vehicle- or antiprogestin-treatment interval followed by a 9 month post-treatment interval for adult, female rhesus monkeys (n = 5/group) of proven fertility and exhibiting regular menstrual cycles. Co-habitation occurred with a male of proven fertility and vaginal swabs were taken to identify the presence of sperm during the treatment (antiprogestin females) and post-treatment intervals (vehicle and antiprogestin females). Results: Mating and vaginal sperm were evident in all antiprogestin females during, and, in both groups, after treatment. Based on ultrasonography, none of the antiprogestin-treated females became pregnant during the treatment interval. However, upon cessation of treatment, pregnancy rates were similar between antiprogestin-treated (3/5) relative to vehicle-treated (4/5) females with live, healthy infants born in both groups. There were no differences between groups in fetal measurements, gestation lengths, live birth rates and infant weights. Conclusions: The reversal of the anti-fertility effects of chronic, low-dose antiprogestin treatment supports the clinical feasibility of potent and selective antiprogestins as potential contraceptives for women.
Original language | English (US) |
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Pages (from-to) | 69-76 |
Number of pages | 8 |
Journal | Human Reproduction |
Volume | 18 |
Issue number | 1 |
DOIs | |
State | Published - Jan 1 2003 |
Keywords
- Antiprogestin
- Contraception
- Pregnancy
- Reversibility
- ZK 137 316
ASJC Scopus subject areas
- Reproductive Medicine
- Obstetrics and Gynecology