Baby is (still) fine

[mmcirvin]

Well, we went for our third ultrasound today, and as far as they can tell, our daughter-under-assembly is in good shape. It seems as if the process is specially designed to worry people, though...


To recap, the first ultrasound around 19 weeks at Melrose-Wakefield, the one Sam described here, found an echogenic focus in the baby's heart. This is a bright spot of calcification that's harmless in itself, but is sometimes claimed to be weakly correlated with Down syndrome; however, iayork mentioned in a comment on Sam's second ultrasound post that he'd discovered that even this weak link was not corroborated by later studies with better statistics. So an echogenic focus essentially means absolutely nothing, especially given Sam's normal quad screen. Nevertheless, they scheduled a second ultrasound at New England Medical Center a few weeks later, maybe for liability butt-covering reasons.

That time, as Sam recounted in her second post, the tech saw the echogenic focus again, but the doctors opined that, given the unlikelihood of anything being wrong, it hadn't really been worth doing the second ultrasound in the first place. Nevertheless, they went ahead and scheduled a third ultrasound, this time because the aspect ratio of the baby's head was a hair below tenth percentile; circumference was normal but it was a little bit long and narrow. This usually just results from the baby being in breech orientation, as she was at the time, but it is apparently sometimes a marker of craniostenosis and they wanted to be sure her head was developing all right.

Well, rationally, "below tenth percentile" isn't a lot to worry about, since on any given measurement, a tenth of all fetuses are below tenth percentile (and another tenth above the ninetieth), most of whom are going to be healthy. And I looked it up—the kinds of craniostenosis that look that way seem mostly associated with genetic syndromes that have all kinds of other markers, and we certainly weren't seeing any of those, nor was there any family history. But this gave me all kinds of horrific visions and worries anyway.

It's astonishing how powerful this effect can be, even if you've imbibed mathematics for decades and got a degree in something vaguely to do with probability. I'm a worrier. (I'm pretty sure I do have a family history of worrying! I hope baby doesn't get it!)

I wish I were as cool a cucumber as Stephen Jay Gould, who got a disease with a median survival time of 8 months, soon figured out by carefully studying the shape and nature of the distribution that, despite the grim median, he actually had a good shot at living a lot longer than that, and was able to convince himself of that prognosis on a deep emotional level (as the postscript says, he died 20 years later of something else, after finishing his masterwork).

Anyway, this time her head shape fell within the range considered normal, as did everything else (the echogenic focus is still there, but still means nothing). This might have been because she's turned head down. And she sure is bigger, though it sounds as if the really impressive growth spurt is still to come. Unfortunately, the pictures from the second and third sessions aren't as photogenically perfect as that profile shot from the first one; to the untrained eye they basically look similar, only bigger and blurrier.

Comments

Re: Darwinian worrying?

[mmcirvin.livejournal.com]

Yeah, we're definitely K-strategy creatures rather than r-strategy. Though that can be obscured when a society has lots of food and a need for cannon fodder.

not necessarily K vs. r

[vardissakheli.livejournal.com]

Parasitic nestlings like cuckoos and cowbirds aren't produced in extra-large numbers, for instance. They just take advantage of nurturing resources other than the parents. Because the parents range so far for food, worrying about their eggs and chicks would be disadvantageous to their survival.

I don't want to think too hard about analogies to class distinctions in human societies.