If you use what is familiar and you are confident in, you will be more confident and probably take better photos. That's probably the overriding factor.
I would shoot MF if at all possible, i.e. if there is enough light. Most hospitals allow you to shoot with bounced flash (it can startle the first couple times but is harmless: flashing for f/8 EI400 is 1600 times less light than a second in full sun but somehow we still have a huge bitchfight on APUG about it occasionally) and that's what I did when my daughter was born.
In terms of finding Portra washed out, was that a scan or an optical print? They both scan quite differently and need different scan settings to render properly. I find the Fuji films far easier to scan accurately (and I suspect they handle fluorescent light better with less green tinge) but if you nail the scan of the Kodak, it will be just as vibrant etc and of slightly finer grain. They both print beautifully to RA4 paper.
Just don't use Ektar or you'll end up with a picture of a wrinkled beetroot. I'd also suggest taking some B&W film too, e.g. TMY2. If you're shooting in a hospital and not flashing, or trying to balance flash with ambient, the lighting will usually be a mix of horrible colours and B&W will hide all of that.