I'm not a midwife, I'm a nurse at a birth center that uses CNMs, but I thought I'd post what we can do.
We *cannot* attend births of multiples, breech (although, how does one know the babe is breech, if one does not do vaginal exams?
), pre-eclampsia, diabetes that is not controlled by diet, and some drug use. We will attend smokers, and occasionally a woman with a history of drug abuse that did not end with pregnancy (ie, she is clean now, but was not at some point during pregnancy). A situation like that is really individualized--our doc meets with them and discusses it with a perinatologist. If the babe might be compromised, he is probably better off being born in the hospital. But if every thing looks okay, that mom and babe are probably better off in an out of hospital situation.
We have in the last year attended VBACs (two women had more than one c-section), women with health conditions (mainly heart conditions. The cardiologists said that nothing different would be done in the hospital, so therefore we felt a birth center birth was safe), adoptions, one incarcerated woman (minimum security), births where the babe has died in utero, and the parents wanted the babe born out of hospital, teens, and 40+ year old moms of 12 or more children.
Even if a mom calls and says she has a condition which we usually refuse, we still go ahead and schedule an appointment, since sometimes we can get around regulations...we really want to do what is best for mom and babe.
Oh, and our biggest babe this year was 10 # 14 ounces. I think our biggest ever has been close to 12#. But we haven't had a 13#er yet! I hope I am there for that!