When is best to test if you don't have a period?

[Purplebluebird]

Hi!
So I had Mirena coil put in about 4 months ago, and since then, my periods have become shorter and lighter. I have however read several threads about women who get pregnant with the coil, and also aware that it's "only" 99% safe. I need to be 100% sure that either I don't get pregnant, or that I find out very early on if I am. So I have decided I will take a pregnancy test every month, just to make sure.

I really really cannot get pregnant, as I am on medications that would be very harmful for a baby, and also I cannot have another child due to my mental health (50% chance of PND, and 50% chance of psychosis).

I have read up on sterilisation, and that is not 100% either, so I might as well stick with the coil, which I get on really well with.

Please can someone tell me when would be the best time to take a test? I am unsure which day my period would start (if it starts at all), as it seems a bit unreliable these days.

If you really don't know when your period is due and are on harmful medications I would be inclined to test every two weeks. You can buy cheap pregnancy tests online in bulk

As you may well know, when you're on the coil you should be checking the strings are still in place regularly: this is probably just as important as the tests for you, since my understanding is that the vast majority of the time the coil fails it's because it's moved out of its proper place. Just to reassure you a bit, my GP told me that if this happened (and so I became fertile again) I would probably experience changes in bleeding, which would be a bit of a warning (I certainly did have a very heavy bleed when I opted to remove my Mirena). Anyway, I think for this reason if I were you I'd pick one date, and either make it easy to remember (e.g. the 1st of the month) or store it in my phone: I'd do this at least monthly, and perhaps every four weeks, since, as you say, your periods might get further and further apart and you don't want to go, say, six weeks between testing, just in case. On that day, I'd both check the strings and do a pregnancy test. That's what I'd do, but if you wanted to be even surer that you'd catch a pregnancy very early on you could do it every two weeks.

I think this is a sensible precaution, but do try and use it as an extra way of putting your mind at rest, rather than a regular source of anxiety. Mirena is a really reliable form of contraception and, although obviously failure does happen, it is rare. Remember that the tiny minority of people who fall pregnant on it are much more likely to post about it than the vast majority who (like me!) used it for years with no incident at all. There's a lot of (very understandable) anxiety in your post, and it did make me wonder whether testing more often than monthly would ramp it up further by keeping it at the top of your mind.

Thanks for replies!
Lisa I do think you're right. I am hugely anxious (started pills for this last week), and this is one of my big worries. I have tried to check the strings, but even after my check up (when dr said it was in the perfect spot) I can't find them! I will try again though.

Perhaps I will write it on the calendar to do it every 3-4 weeks or something. That way I will find out quickly, but without having to do it "all the time" if you know what I mean. I wish there was something 100% safe.

You are giving this a lot of thought purple, far more than i did when i had mine in! I had no periods with it and only managed to feel the wires once in 5 years. i just could never find them and never did a pregnancy test either. I was quite young though, didn't even cross my mind

It's only because I have gone through a pregnancy and have a little one, that I know how bad it could go if I had one more (plus obviously my new medications). I just have to be really certain it won't happen - or if it does, that it's not too late to stop it, which sadly would be my only option.

I will try to find the threads, and hope for the best!