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Dr. Owen
Dr. Owen, OB/GYN (Doctor)
Category: OB GYN
Satisfied Customers: 55754
Experience:  Board Certified: Ob/Gyn & Preventive medicine, US Medical Graduate
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using plan B after or during ovulation

Resolved Question:

using plan B after or during ovulation
Submitted: 6 years ago.
Category: OB GYN
Expert:  Dr. Owen replied 6 years ago.
Hello, and I am pleased to help, use of my answers are for educational purposes only.
What specifically is your question?
Customer: replied 6 years ago.
I am looking for published research into efficacy of using plan B prior to or post ovulation event. Specifically when would be the best time in a woman's cycle to use plan B? It appears from what I've read that the primary mechanism of this method is to delay ovulation. If that is the case - how long is ovulation delayed, or is it totally suppressed for that cycle? Also, if that is the case, is plan B ineffective if taken on the day of or subsequent to ovulation?
Expert:  Dr. Owen replied 6 years ago.
Where are you getting your information about 'delaying' ovulation?
Customer: replied 6 years ago.

most of the sites I've read emphasize the action of the hormone on preventing follicular rupture. My question is, how can this method work if fertilization has occurred and are there any statistics on efficacy pre vs. post ovulation? Is my question understood?

Put it this way - if a woman were planning to take EC because she plans to have sex during the time of her ovulation, should she plan to take the dose prior to ovulation, or just after?
Expert:  Dr. Owen replied 6 years ago.
Actually plan B does NOT work once fertilization has occur (altough what ) what I see you are saying - but plan B causes Progesterone Withdrawal - so hence this causes any embryo NOT to be able to implant. This is why it is important to get this pill in your body before 72 to 96 hours after you have sex.
So, it does NOT matter if before or after ovulation - I recommend taking within 72 hours of having had sex.
I hope this helps, Please click on ACCEPT, thank you.
Customer: replied 6 years ago.
I don't feel that my question was answered. You state that it does NOT work after fertilization, but that it also can prevent implantation, which is another way of saying it DOES work after fertilization? I am confused.
Expert:  Dr. Owen replied 6 years ago.
Do you understand the process of HOW everything works and how pregnancy really occurs?
Customer: replied 6 years ago.
Yes, sir, I do. I know that a woman ovulates and has a viable egg once a month that can be fertilized for 12-24 hours. My question is, does Plan B work if that egg has been fertilized? An embryo is a fertilized egg, is it not?
Expert:  Dr. Owen replied 6 years ago.
Okay - you have to step back - all moring after pills rely on the single mechanism of Progesterone Withdrawal - so hence as LONG as implantation has not started - then it does NOT matter if the egg is fertilized or not. And, this is why you can wait up to 72 to 96 hours after sex to have this occur, but the problem is that plan B (or similar progesterone pills) do not cause the withdrawal to occur for at least 2 to 8 days later - so this is NOT dependent upon fertilization at all - it depends on implanation - because one the embryo is implanted, the plan B will only enhance a pregnancy since it is progesterone and this is what the Corpus Luteum makes (which is progesterone).
I hope this helps, Please click on ACCEPT, thank you.
Customer: replied 6 years ago.
so is Plan B more effective before or after ovulation?
Expert:  Dr. Owen replied 6 years ago.
Neither - The point is to make sure that the uterus is 'unfriendly' to an embry - so hence why it is recmmend to do this pill within 72 to 96 hours of have had sex.
Please click on ACCEPT, thank you. We only get compensated for answering all of your questions when you ACCEPT, thank you
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