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twinsTwo offspring from a single pregnancy. Twins may be derived from a single fertilized egg that separates into two after the first division. Such monozygotic twins are genetically identical. Alternatively, twins may be derived from two eggs fertilized at the same time. Such twins are dizygotic and non-identical and in about half the cases are of different sex. The rate of monozygotic twinning in humans is fairly stable at 0.35 per cent, while the rate of dizygotic twinning varies more widely around an average of 1 per cent of pregnancies.
twinstwo offspring born at the same time of the same mother. See DIZYGOTIC TWINS, MONOZYGOTIC TWINS.
Patient discussion about twins
Q. anything a mother should know about the last period of twin pregnancy? she is in her 7th month and starting to be real heavy... her legs hurt like crazy. anything to help her with?
Q. Is there a bigger risk of autism for the newborn in twin pregnancy?