So, it's probably no surprise to many of you that I have been positively obsessed with the births of the Morrison and Masche sextuplets. After all, we did injectibles + IUI, triggered with 4 to 6 mature follicles, and got pregnant with twins and a maybelet. To a certain extent, it's just chance that the world isn't busy chattering about that stupid Emma B woman, so baby-crazy that she was willing to have a litter, with her cowboy doctor whose only concern was his success statistics.
Certainly, whenever I read about high-order multiples, I get a case of the shakes. It could have been me, with the six 22-week preemies rather than the healthy 36-week twins. It's even possible that it still might be me, someday down the road. After all, we plan to start treatment if necessary to conceive a third baby, and we haven't ruled out beginning with an IUI cycle before proceeding to IVF. I think to myself, we were so very lucky.
But you know what? We weren't lucky, really. Despite having all those follicles, the odds were overwhelmingly in favor of us conceiving no more than one baby. It's tough to get good statistics on IUI, because they're not reported to the CDC, and it's not as easy to measure follicles as to count embryos transferred. Still, we know enough to engage in drive-by statistics.
The overall IUI success rate is estimated at 15-20%. Since this includes IUIs with a single follicle and multiple follicles, let's assume that any given egg has at most a 15% chance of developing into a viable pregnancy. (This number is almost certainly on the high side, but this isn't a scientific paper here, just an off-the-cuff analysis.) So, if you undergo an IUI with six mature follicles, your chances of sextuplets are:
0.15 * 0.15 * 0.15 * 0.15 * 0.15 * 0.15 = 0.0000114 = 0.00114%
In plain English, about one in 100,000 women to do an IUI with six follicles will conceive sextuplets. For comparison, you are 17 times more likely to die in childbirth. If you are a no-risk singleton mother at term, your baby is 62 times more likely to die during birth.
One in 100,000, y'all. Think about how absolutely tiny that is. It's a 99.999% chance that it won't happen to you, even though you have six mature follicles. Wouldn't you think that 99.999% is a sure thing, that there was no way you would be the one to have the sextuplets?
Or let's ask ourselves, how likely is it that our six-follicle woman will have quads or quints, rather than sextuplets? Those are still pretty bad, right? Well, the math says that this woman -- let's be hypothetical and call her Emma -- has a 67% chance of conceiving twins (0.15 * 0.15 * 30 possible follicle combinations). This is no surprise, given that they're crawling around her living room floor at the moment. Her chances of triplets drop a whole lot, though, to just 6.75% (0.15 * 0.15 * 0.15 * 20 combinations). Emma's chances of quads are another order of magnitude lower, at just 0.7%, just 7 out of 1000. Finally, there is only a 0.045% chance of quints, which is pretty tiny. Add the risk of quads, quints, and sextuplets together, and there is a 99.25% chance that Emma will NOT get pregnant with high-order multiples, even though the conditions are right for her to do so.
Is it such a terribly stupid decision, to do something that has a 99.25% chance of working out OK? There are certain risk levels we all agree are unacceptable, especially when we're talking about children's lives and health. Other cases are a lot less cut-and-dried, and to me, this level of risk is one of them. If you look at the numbers, it's easy to conclude Brianna Morrison and Jenny Masche were no more cavalier about high-order multiples than I was, just overwhelmingly unfortunate.