Congress passed the Partial-Birth Abortion Ban Act. A partial-birth abortion is defined in the Act as any abortion in which the death of the fetus occurs when 'the entire fetal head or any part of the fetal trunk past the navel is outside the body of the mother.' Dr. Leroy Carhart and other physicians who perform late-term abortions sued to stop the Act from going into effect. The plaintiffs argued that the Act could apply to a more common abortion procedure known as 'D&E' ('dilation and evacuation'), as well as to the less common 'intact D&E,' sometimes called D&X ('dilation and extraction'). With this application, the Act would ban most late-term abortions and thus be an unconstitutional 'undue burden' on the right to an abortion. The plaintiffs also argued that the Act's lack of an exception for abortions necessary to protect the health of the mother rendered it unconstitutional. A federal District Court agreed and ruled the Act unconstitutional on both grounds. The government appealed and argued that the Act only bans a narrow category of abortion procedures and that a health exception is not required when Congress determines that a banned abortion procedure is never necessary for the health of the mother. The Eighth Circuit held that a health exception is required for all bans on abortion procedures when 'substantial medical authority' supports the necessity of the procedure. The Circuit Court ruled that the ongoing disagreement among medical experts over the necessity of intact D&E abortions was sufficient to establish that the Act was unconstitutional without a health exception. The Circuit Court did not reach the question of whether the Act was so broad as to qualify as an unconstitutional 'undue burden.'