I will note up front that I'm not a medical professional so I can only offer what I'd consider common sense tips that my wife and I used while we were expecting:
How likely are you to get illnesses that might be a cause for concern? Gastroenteritis, for example, is nasty at the best of times but can be more of an issues while pregnant.
How confident are you in the local health care if something goes wrong with your pregnancy? What about language barriers? If something, god forbid, goes wrong, your first point of contact will likely be a local health care centre. Will this be an issue?
You appear to have covered the physical extremes (altitude, heat) but obviously what activities you hope to do in the destinations will play a part in whether it's an enjoyable trip.
Most countries do not offer restrictions on the travel of pregnant women, but it doesn't hurt to have a doctor's certificate stating your due date in case of over-zealous airline attendants (most airlines have restrictions on travel of pregnant women after a certain date) or customs officials (countries that give out citizenship upon being born on their soil can have restrictions to try to ensure pregnant women will return home before giving birth).
Are you experiencing any nausea during pregnancy? This can be exacerbated at altitude (Nepal) or in flight. My wife went from next to no nausea during the rest of her pregnancy to crippling nausea while in flight. This can be very tough on long flights.