Multifetal Pregnancy Reduction. See: fetal reduction


The loss of a pregnancy before the fetus is 24 weeks old.

Monochorionic twins

Twins sharing a gestational sac and placenta. This bears higher risks for the fetuses during pregnancy and birth. It can only occur in identical twins because they develop out of the same egg, part of which develops to form the placenta.

Monozygotic twins

Twins who are derived from a single fertilised egg (zygote). Monozygotic twins form when one fertilised ovum separates into two identical zygotes.


A state of disease.


Death. The risk of mortality refers to the number of patients who die after a medical intervention or event.