What I need is for her to develop a complication that would satisfy the following conditions:
1. Serious and almost certainly fatal without access to a modern hospital, but treatable if she is sent to said hospital on time.
2. This condition has to be diagnosed under the circumstances I described - that is, by a family doctor, but without machinery of any kind, except what you find in a local pharmacy. The diagnosis has to be fairly certain - not "there are a dozen things it could mean and one of them is serious", more like "9 chances out of 10 say it is a very bad thing that will kill her".
3. Once it is diagnosed, there has to be at least a few days before the situation becomes dire. It cannot be something that requires her to be in the hospital within a matter of minutes, like a heavy hemorrhage.
If necessary, I could have the pregnant woman have some kind of chronic health condition, but it has to be something that was not too much of a problem before pregnancy.
What I tried to research, through Google and Wiki:
1. A breech birth. It doesn't seem to be dramatic enough, the baby can always turn before the delivery date, or a doctor might be able to do something during the delivery.
2. Placenta previa. This seems serious enough, but the diagnosis seems to require ultrasound. The painless bleeding during the second or third trimester is also mentioned as a symptom, but I am not sure what kind of bleeding that would be. Could it be something mild every now and then, or will it just continue on and on, once started? If the former is true, this will work for me.
3. Placenta accreta. Looks like this also requires scans to diagnose before delivery.
4. Eclampsia. For preeclampsia, the high blood pressure should be easy enough to spot, as well as vomiting and headaches. Don't think protein in urine can be found without a lab. But whether or not it will turn to eclampsia seems uncertain, and that will not work for me.
Also searched for "pregnancy complications" and "reasons for c-section."