OPK accuracy? and how carefuly should I be?!?!

[daurelia]

Hello all,

I'm new here :) You'll probably see a bit more of me as the spring/summer continues...

How accurate are OPKs? The box says 99%, but I'm seriously confused by what they're telling me...

I have been charting my cycles and successfully avoiding pregnancy for 2.5 years. I've always had EWCM on a few days from around 9-13, my temp spike the morning of the 13-16, every cycle. So I'm very regular, with textbook cycles. 

My husband and I are going to start TTC next month, and I wanted to try these OPKs this month to see if I'm as accurate as I think I am. I did one on day 11, and it was negative.  I took it again on day 13, also negative. Then I had a temperature spike on day 14 (today is day 14) (and I had EWCM on days 10-12).

Further complicating this: we had condom-free sex on day 12, saying "what the hell, it's so close to the time we are going to try anyway, let's just see what happens". YIKES

Meanwhile, the reason we were going to wait another menstrual cycle is because I wanted to get a little tipsy with friends after a final exam next week, and we are going to Mexico the week after and I wanted to eat/drink whatever worry-free.

my two questions are:

1) how accurate do you think OPKs are when they conflict with a crystal-clear textbook FAM cycle? I'm feeling kind of anxious that maybe I'm not as fertile as I always assumed I was...

2) given the above information, how careful should I be in the next 2.5 weeks when it comes to drinking? Would you indulge in a drink or two after the exam, or in Mexico, were you in my shoes?  I'd really love to enjoy a few toasts with my friends as well as margaritas on the beach, but if there's a decent chance I'm pregnant, I don't want to hurt my little clump of dividing cells :)

Thanks for any insight!

[AdinaL]

Okay, OPKs are different in how you use them.  

If you took them every single day for your entire cycle, you would be able to watch the line get darker and darker until it got it's darkest right before you ovulate, and then it would get light again.

The thing with OPKs is how dark the line is, and the trick is to take them several days in a row at the same time to gauge when you are most fertile.

So, given that you took them a couple days apart you might have missed your positive in there somewhere as all signs pointed to ovulation other than the OPK.  Check the product instructions as well I think that you can ovulate 12-36 hours after you get that positive test (at least that's what I remember from when I was ttc - which was over 5 years ago now. LOL)

I hope that helps! :)

[daurelia]

Thank you for this info about OPKs!! I don't think I understood the subtlety of these tests before. I took "99% effective" at face value...

[AdinaL]

They are quite effective at showing the LH surge before ovulation, but yeah, they aren't a yes or no type thing like a pregnancy test, it took me a couple cycles before I got how they were supposed to work.  :)