On to April — and a little bit of juggling of probabilities

Not pregnant again this month.  On to April.

I was pretty sure I wasn’t pregnant yesterday (temps, spotting), so while I’m rather resigned to the arrival of my period today, I got most of the tears out of my system yesterday.

I did also take a proactive step yesterday, though: I called my RE’s office and asked them how long I should be trying on my own before coming back for help.  The nurse I talked to was reasonably helpful, and said that given my history, she thought probably 3-6 months of trying on our own would be plenty.  She suggested I make an appointment in May, which I gladly did.  That’ll be 9 months after the loss of our daughter, and we’ll have gotten in five tries of our own (with help from OPKs and BBT charting) before then.

It’s immensely comforting to have that date on my calendar.  I keep telling myself we haven’t been trying long, and it still might work out, but things just feel different than they did before I became pregnant with our daughter.  The lack of any implantation spotting even though it happened both times we timed things properly before I got pregnant.  Lighter periods, even compared to my already-light pre-pregnancy periods.  The new element of intrauterine adhesions.  These things are scaring me.  It’s nice that most of our pre-pregnancy infertility workup was normal, so there are a lot of things I know I don’t need to worry about (my husband’s fertility, for one — since our workup, the only thing that’s changed for him is that he’s a year older!).  Right now I’m mostly worried about two things that might have changed since before the loss of our daughter: (1) the potential for tubal scarring, and (2) the possibility that my endometrium might be damaged more than they realized by the late postpartum D&C.  Maybe I’m worrying unnecessarily… and maybe I’m not.  Either way, I’d really like to ask my doctor about it.  Having the date on my calendar makes me feel that my efforts will be finite, that help is on the way.

I did a little calculation the other day.  I’ve found several references that give average probability of conception based on how many days before ovulation you have sex, including this paper.  I’ve got my dates of ovulation for the past several cycles pinpointed pretty well by a combination of OPK and BBT monitoring, and I have records of which days we had sex.  So far, we’ve managed to have sex on the highest-probability day (one day before ovulation) for each of three cycles. If you take the average between the two studies listed in the paper linked above, a couple with average fertility would have approximately a 35% chance of getting pregnant each cycle if they have sex on the day before ovulation.  That means that there’s about a 73% chance (that’s 1 – 0.65^3) that we should be pregnant by now, if we have average fertility — or, looking at it the other way, there’s a 27% chance that a couple with average fertility would not be pregnant by now, so we may just be the unlucky 1/4.  That doesn’t seem too improbable.

If we keep timing things properly, though, those probabilities start to drop pretty steeply.  By the time we see our RE after 5 tries, there’ll be only about a 10% chance that we’re consistent with a couple with normal fertility.  If we then go through a month or two of testing, bringing us to 7 well-timed tries, that brings the probability down to 5% that we’re consistent with normal fertility.  Even if you take the lower-probability study as gospel, with a 30% chance of success given sex one day before ovulation, 6 months of trying still gets you to the p < 0.1 level (0.7^6), and it only takes a little more than 8 tries to get to p<0.05 (0.7^8). Of course, there are plenty of reasons to believe that we have less-than-normal fertility anyway, but that’s all the more reason to ask for help sooner rather than later.  May will also be almost exactly two years after I first tossed my birth control pills, so it seems fitting to go back to the RE around then.

Most of the magazine articles you read give a couple a 20% chance of success each cycle, but I think they’re probably assuming that you’re just randomly having sex every 2-3 days, not approaching baby-making with all the precision of an intercontinental ballistic missile.  At that more relaxed rate, a year of trying makes sense, because it’s only after a year that you cross the p<0.05 threshold.  But we are long past the relaxed approach stage.  (It almost killed me this week when I saw a colleague/friend who is 6 months pregnant with her second and she happened to mention that “we weren’t even really trying yet, and I didn’t realize I was pregnant until I was halfway through the first trimester!”  Ugh.)

Anyway, I was worried that my RE’s office would tell me to go away for a year, but thankfully they didn’t.  Having an end to our solo baby-making efforts in sight is providing me some comfort as I deal with the miniature loss of the idea of our Thanksgiving baby.


4 thoughts on “On to April — and a little bit of juggling of probabilities

  1. TryTryAgain

    Ah I’m sorry to hear that, I was hoping to hear from you. But great that you’ve got the next steps in place, that makes such a difference I always think. Lots of love xxx

    1. lyra211 Post author

      Thank you for checking in, and for the sympathy. 🙂 I’ll be waiting to hear your results soon too. We’ll both get there eventually!

  2. theskyandback

    I’m sorry this last month was not your month. I think it’s great that you have an RE appointment on the horizon. Maybe that reassurance will be all you need. Fingers crossed that it happens for you next month! Xo.

  3. lyra211 Post author

    Thank you. I sure hope that reassurance will be all that I need — honestly, it doesn’t feel like it right now (bit of a meltdown overnight), but it is comforting to have it there nonetheless.


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