Re: Vasectomy (permanent?)
That's not necessarily true - they're not entirely sure exactly how NuvaRing prevents all pregnancies. According to the prescriber information leaflet for nuvaring:
Originally Posted by KelseyH
NuvaRing does not prevent pregnancy or implantation - just ovulation. I haven't had the chance to use it but my bff uses it and she loves it. I had my Mirena removed before my 1st pp ovulation for those exact reasons (oh yeah, and crazy mood swings, sucky metabolism, etc). I couldn't live with myself if an egg was fertilized and Mirena just made the environment too hostile for it to survive.
"Although the primary effect of this action is inhibition of ovulation, other alterations include changes in the cervical mucus (which increase the difficulty of sperm entry into the uterus) and the endometrium (which reduce the likelihood of implantation)."
Clearly it doesn't always prevent ovulation (because there is a failure rate), so it's hard to know how often there is breakthrough ovulation but no pregnancy due to preventing implantation. This is true of all hormonal birth control (not just nuvaring).
If you got to nuvaring.com and click on prescribing information, you can get to the document where my quote is from. Bottom of the first page in that document.
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