Understanding Menstruation and Pregnancy

[Curious.Isa]

Dear Scarleteen,

I have a question regarding menstruation and pregnancy. I have read related articles and discussions on your website, and whilst some argue that a period definitely indicates a pregnancy has not and will not occur from a risk prior to that period, some state that in this case pregnancy is 'highly unlikely'. I therefore question if there is any chance, no matter how small, in which a period does not confirm a pregnancy will not happen from a risk occurring at any time before that period begun.

From my understanding, when one has a period it indicates that one did not become pregnant (i.e. a fertilised egg did not implant into the endometrial lining) in the days/weeks directly preceding Day 1 of that period. My concern is if a risk occurred very close (i.e. 1-5 days) before a period then started. Could the person become pregnant in the days/weeks directly following Day 1 of that period, from this pre-period risk? My reasoning is that sperm could survive under ideal conditions for up to 5-7 days. Therefore, if ovulation occurs a couple of days after Day 1 of that period, sperm could theoretically fertilise the released egg and this fertilised egg could then implant itself onto the endometrial lining - marking the start of the pregnancy. Therefore, although the person may not yet be pregnant from the pre-period risk at the time the period begins, she could become pregnant in the days following Day 1 of this period. In this case, having a period does not necessarily confirm that someone will not become pregnant from a risk occurring before that period started. I would appreciate if you could point out the flaws in this argument. I understand that menstruation is not an ideal condition for sperm to survive, but I was just wondering if there is any minuscule chance in which some could. After all, you always warn us against having unprotected sex during a period.

If there is indeed a chance, no matter how small, that pregnancy is possible in the above situation, how many days before the start of a period would a risk have to occur in order for the period directly following that risk to 100% confirm pregnancy has not and will not happen from said risk?

Finally, may I know how many days after a risk could pregnancy (implantation of the fertilised egg) occur? If I had a risk, then five days afterwards had a period, then received another period 5 weeks after the risk, does this 100% confirm that I am not, nor will become pregnant, from that risk 5 weeks ago? My understanding is that this is correct, because (a) sperm cannot survive that long and (b) if implantation occurred in the days between the start of my first and second periods, then my second period would not have arrived.

I just would like to know if I have missed anything out in the way I understood this, which could indicate that there was indeed a minuscule chance in which pregnancy have occurred or could still occur. For example, I have this fear that sperm may have survived longer than normal, or perhaps an egg was fertilised between the start dates of my two periods and will implant after my second period occurs (5 weeks after the risk). Call me silly, but I just need to know if this is 100% impossible or in any way possible.

Really sorry for all the questions, I've just been keeping it to myself for a long time now and really want to go back to the days when having my period completely took away all my fears no matter when the risk occurred prior to the period!

[Karyn]

From my understanding, when one has a period it indicates that one did not become pregnant (i.e. a fertilised egg did not implant into the endometrial lining) in the days/weeks directly preceding Day 1 of that period. My concern is if a risk occurred very close (i.e. 1-5 days) before a period then started. Could the person become pregnant in the days/weeks directly following Day 1 of that period, from this pre-period risk? My reasoning is that sperm could survive under ideal conditions for up to 5-7 days. Therefore, if ovulation occurs a couple of days after Day 1 of that period, sperm could theoretically fertilise the released egg and this fertilised egg could then implant itself onto the endometrial lining - marking the start of the pregnancy. Therefore, although the person may not yet be pregnant from the pre-period risk at the time the period begins, she could become pregnant in the days following Day 1 of this period. In this case, having a period does not necessarily confirm that someone will not become pregnant from a risk occurring before that period started. I would appreciate if you could point out the flaws in this argument. I understand that menstruation is not an ideal condition for sperm to survive, but I was just wondering if there is any minuscule chance in which some could. After all, you always warn us against having unprotected sex during a period.

You're correct that a period indicates that pregnancy did not occur during the previous cycle. The first day of a period is the first day of a new cycle, and so that period starting means that pregnancy hasn't happened since the first day of the period before. (Hope that makes sense.) However. You are also correct that just because a pregnancy didn't happen in the previous cycle, doesn't mean it can't happen as a result of a risk near the end of that cycle: that's why, as you know, we advise that even during a period, unprotected sex still poses a risk. (It's incredibly unlikely, given that it would be unusual for ovulation to occur so soon after the end of a period that way, but not impossible.)

Per how many days before the start of a period a risk would need to happen in order for a period to confirm that pregnancy hasn't happened, I don't know that there's an answer to that question: there are just too many factors to consider.

Finally, may I know how many days after a risk could pregnancy (implantation of the fertilised egg) occur? If I had a risk, then five days afterwards had a period, then received another period 5 weeks after the risk, does this 100% confirm that I am not, nor will become pregnant, from that risk 5 weeks ago? My understanding is that this is correct, because (a) sperm cannot survive that long and (b) if implantation occurred in the days between the start of my first and second periods, then my second period would not have arrived.

That's absolutely correct.

Since you've got all the information, and it seems like you understand it, I'm wondering if there's something else at play here: are you comfortable with the method(s) of birth control (if any) that you're using, or have you had a real risk that you're concerned about? Are you feeling comfortable with the kinds of sex that you're having? When someone has and understands all the necessary information in a situation like this, and yet is still worried, that's often an indication that their concern isn't about a lack of facts, but instead is related to some other concern or anxiety.

[Curious.Isa]

Hi Karyn,

Thanks so much for your response and the information. I think I may have some sort of anxiety or OCD, but have been trying to rationalise and personally deal with it. During periods of high stress I find that these worries are very difficult to shrug off and I keep coming back to them. I guess even though I feel I have the right information, I keep on worrying I may have missed out on something / not considered all the possibilities.

I do apologise, but just to confirm there is absolutely no way I am or could become pregnant from that risk 5 weeks ago, having had two periods since the risk as described. Is it at all possible for a fertilised egg from the risk 5 weeks ago to implant after the first day of my second period since the risk (thus making this second period possible)?

Thank you once again.

[Karyn]

You already know the answer to that question. Asking for reassurance is something we know keeps people stuck in anxiety rather than helping, and so I'm going to ask that if you need to check the information you have, that you look at what I have already told you.

In terms of dealing with anxiety, have you considered seeking out any kind of counselling or therapy for it? I get wanting to deal with it on your own, but it can be useful to talk to a mental healthcare professional to develop some strategies for dealing with your worry when it arises.

[Curious.Isa]

Hi Karyn,

I understand and agree that reassurance through reconfirming facts I already know will just feed the anxiety. However, my last remaining bit of concern (talking to you and having my understanding confirmed has honestly helped a great deal) comes from having incomplete information - I don't know how long after a risk implantation could occur.

Not knowing this made me question if there is any chance a fertilised egg from the risk 5 weeks ago could implant after the second period since that risk. From the information I have and which you confirmed, I understand that if implantation did occur after my first period, I would not have had my second period. My concern is if a fertilised egg could somehow survive until after a second period comes without implanting, then implant 5+ weeks after the risk?

Perhaps it's better for me not to try and think of all the scenarios in which that risk could lead to pregnancy, and focus on the fact that I had two normally timed periods since the risk and this on its own 100% confirms that I have not and will not become pregnant from the risk?

Either way, I would be really grateful if you could answer both my questions - I feel I would then have all the knowledge I need to feel confident. No more questions after this. In terms of OCD/anxiety, today I have booked an appointment to see a doctor who I hope could refer me to CBT (Cognitive Behavioural Therapy) if necessary. I trust that'll make things better in the long-run!

Thanks so much for your help thus far.

[Onionpie]

Hi Curious.Isa. The thing is, you say your knowledge is incomplete in this one area, but it actually is not. If implantation happening five weeks after a risk, and AFTER periods have already happened, was something that was actually realistic and made an exception to any of what karyn has already said (and you have already read) then that information would have been provided. But it hasn't, it doesn't change anything.

I think the thoughts that you're having like these are a really common and understandable part of when someone has anxiety and hyperfocuses on all the possible negatives and all the ways something terrible just might be able to happen. I think you hit the nail on the head when you said "Perhaps it's better for me not to try and think of all the scenarios in which that risk could lead to pregnancy". That is exactly what you have to do.

Have you done any self-directed research on anxiety or OCD? Have you come across anything that talks about different ways of coping with anxiety? Can you think of any coping strategies you already have that you can use in this instance? That is, something that helps you take your mind off of whatever anxious situation you're focusing on, and help you to relax and get yourself out of crisis mode and thinking more clearly? If not, we can talk to you a lot more about that. However, I think it's important that we draw a line here with anymore "clarifying" questions because it's pretty clear that when you're feeling like this, you start to think up questions that aren't actually realistic and just work to make you feel worse.

So -- what we can help you with, moving forward, is finding ways to handle these feelings and help stop yourself from getting to this point of anxiety, and we can also help you find some in-person resources around this. What would you like to focus on right now?