Fun mathematical model to announce pregnancy to husband My husband is a mathematical modeler and I would love to give him a model to announce to him that we're pregnant! He is a pharmacometrician and a neurologist and often uses R, PKPD, and Markov models, but also works avidly with other mathematics (though I wouldn't be able to tell you what). Is it possible to have some type of model/equation to equal pregnant/biological chemistry of being pregnant? My knowledge on these subjects are minute so any help would be greatly appreciated!

Congratulations!

Here's a possible fun approach:

Ask him to convert the following to base $36$:

$\frac{222,931,132,460,168,112}{332,378,040,005,725}$

The answer, in decimal form, is:

$670\frac{237,845,656,332,362}{332,378,040,005,725}$

Converted to base $36$, where $a=10$, $b=11$, and so on up to $z=35$, that works out to:

$im.pregnant\overline{impregnant}_{36}$

He should probably use Wolfram|Alpha, and make sure he clicks the "More digits" button, until it sinks in.