Dear Mercury, I am not an ultrasound technician but I have a Ph D in the sciences and I have had children, bli ayin hara – please bless us that we should have more. I once asked an ob-gyn why most machines are not calibrated, which is simple and easy to do, and he replied to me it’s not done because it is unnecessary, and the few machines that are properly calibrated are more than adequate in number, to deal with those few cases that require it. As you say, fluid, CTG and activity are the relevant parameters.
I do not think it is strictly an aveira to get a pet, I think it’s a figurate expression, like humiliating a person in public is not mamash like murdering. I do think it’s not a good idea, especially in modern times, as we may consider them as “family members” like some nonjews do, and this is an aveira. We had a mitzva to have (kosher) pets once, just before we left Mitzrayim, it is very difficult if you think about it, have children grow affectionate with a lamb, a sweet gentle lamb, hug it, have it respond to our calls, we see the lamb growing day by day, getting stronger and more beautiful — and then one day we shecht it, with the children watching. Nowadays if we had to do, it would be very difficult, and it seems to me we have a weakness, and we should put a fence. Plus, it takes much money, much emotional drain, much time and effort (such as cleaning after them, keeping nonkosher pots, pans and dishes, figuring out what to do over Pesach, etc) which I believe we should direct elsewhere, starting with our own family members and then, if we still have money and time we wish to donate, there are many worthy causes to devote one’s time and money and help Yidden, which, differently from the pets, is an obligation and is the very reason we are in the world.
TCG, you have already explained us that your cats are neutered, which is an issur d’oraita, so your cats are the perfect example of the choice of keeping pets leading to another aveira. In addition, I doubt you would spend everything you have, much less take loans, to help a fellow Jew.