Unassisted childbirth comes with risks. Numerous national medical societies, as well as midwives' associations, have cautioned against unassisted childbirth. Twenty percent of all previously normal pregnancies turn into complications and high-risk situations during labor, which could necessitate assistance from trained medical professionals. OB-GYNs do not recommend home births, even when attended by a medical professional, if the mother has hypertension or when a breech birth is expected. A 2010 meta-analysis of existing research concluded that planned home births had a three times higher mortality rate for babies.