Brain death is a concept used in situations in which life-support equipment obscures the conventional cardiopulmonary criteria of death, and it is legally recognized in most countries worldwide. Brain death during pregnancy is an occasional and tragic occurrence. The mother and fetus are two distinct organisms, and the death of the mother mandates consideration of the well-being of the fetus. Where maternal brain death occurs after the onset of fetal viability, the benefits of prolonging the pregnancy to allow further fetal maturation must be weighed against the risks of continued time in utero, and preparations must be made to facilitate urgent cesarean section and fetal resuscitation at short notice. Where the fetus is nonviable, one must consider whether continuation of maternal organ supportive measures in an attempt to attain fetal viability is appropriate, or whether it constitutes futile care. Although the gestational age of the fetus is central to resolving this issue, there is no clear upper physiological limit to the prolongation of somatic function after brain death. Furthermore, medical experience regarding prolonged somatic support is limited and can be considered experimental therapy. This article explores these issues by considering the concept of brain death and how it relates to somatic death. The current limits of fetal viability are then discussed. The complex ethical issues and the important variations in the legal context worldwide are considered. Finally, the likelihood of successfully sustaining maternal somatic function for prolonged periods and the medical and obstetric issues that are likely to arise are examined.