These agents cause formation of a thick cervical mucus that is relatively impenetrable to sperm; they may increase tubal transport time and also cause endometrial involution [which would hinder the development of any fertilized ovum]. ”
कुछेक अनुसन्धायक दावा करते हैं कि प्रोजेस्टिन - ओन्ली गोलियों से, “४० प्रतिशत प्रयोक्‍ताओं में सामान्य अण्डोत्सर्ग घटित होता है । ”