Hi Jen,

It's up to the individual midwife and the individual woman as to whether or not she births at home. There is no set criteria for who can or can't birth at home. It's the woman's choice and obviously the midwife will decide if she is comfortable attending that woman. If not, the woman can just look for another care provider who is happy to attend her birth. I don't think you can just willy nilly relegate issues into "high" or "low" risk, it's never that clean cut.
Independently Practicing Midwives (IPMs) are not regulated in Australia, however there are some criteria for offering a homebirth that are generally accepted. The woman must be in good general health without any medical conditions that would increase the risk of complications during pregnancy and birth. They should be within reach of medical support, which tends to disqualify women in isolated rural areas; the pregnancy should be a normal single pregnancy, as having a multiple birth carries an increased risk of complications; the woman should be free of any substance abuse issues; some midwives choose not to offer homebirth to women who smoke cigarettes, as nicotine smoking can increase the risk of low birth weight babies; some midwives will not offer homebirths to women who are not willing to breastfeed from birth; and if the woman has a live-in partner, then they must also not have any substance abuse or aggression issues, and must be generally supportive of the choice.

Theres the criteria off the top of my head. The big ones are multiple births (a big no-no) and breech birth (frowned upon by the medical establishment, but the evidence against vaginal breech birth being safe is proving to be quite dubious, so many midwives are choosing to attend them now; sadly, the techniques in supporting a woman through a breech birth have been lost to our current generation of midwives and many are having to re-learn these skills).

Its interesting to note (I don't know exact figures and I am in the process of researching them) that the last midwife in Australia to be succesfully prosecuted for negligence in Australia was Maggie Leckie-Thompson; that was nearly two decades ago, and was as a result of a complaint from two obstetricians that is generally (among the midwifery community, anyway) accepted as being politically motivated. Obstetricians either sued by families, or prosecuted by the courts for negligence, much more frequently. There is little doubt, and the research evidence from countires such as the UK, the US, Europre, and Australia supports this, that homebirth is a safe option, with a much lower incidence of potentially damaging intervention, than hospital birth, for women who meet some basic criteria, such as those outlined above.