3 doctors weighed in:
How does estrogen in contraception pills prevent fertilisation in the first place?
3 doctors weighed in

Dr. Hugo Ribot
Obstetrics & Gynecology
2 doctors agree
In brief: Works in pituitary
The estrogen in the pill alters the normal feedback to the pituitary gland, which in turn prevents the changes (rise) in fsh (follicle stimulating hormone) and lh (luteinizing hormone) levels which lead to ovulation, which is the release of the egg from the ovary.
Since the egg doesn't leave the ovary, it is not physically accessible for the sperm to fertilize it.

In brief: Works in pituitary
The estrogen in the pill alters the normal feedback to the pituitary gland, which in turn prevents the changes (rise) in fsh (follicle stimulating hormone) and lh (luteinizing hormone) levels which lead to ovulation, which is the release of the egg from the ovary.
Since the egg doesn't leave the ovary, it is not physically accessible for the sperm to fertilize it.
Dr. Hugo Ribot
Dr. Hugo Ribot
Thank
Get help from a real doctor now
Dr. Adam Levy
Board Certified, Obstetrics & Gynecology
33 years in practice
1M people helped
Continue
108,000 doctors available
Read more answers from doctors