Incidence of multiple pregnancy:
The fallowing factors are associated with higher incidence:
-familial:wether the wife's or husband's family has a history of multiple pregnancies
-induction of ovulation
-maternal age: incidence increases with increasing age up to 40
-previous multiple pregnancy
Types of multiple pregnancies:
1.Binovular (Dizygotic=non-identical) Twins:
-developed from two separate ova which may or may not come from the same ovary and fertilized by two separated spermatozoa.
-the twins are of the same or different sex
-the similarity between them is not more than that between members of the same family
-they have two placenta,two amnions,two chorions and two umbelical cords
-binovular twins are 4 times more common than the uniovular variety.
2.Uniovular (Monozygotic=identical) Twins:
-developed from a single ovum which after fertilization by a single sperm has undergone division to form two embryos
-the twins are of the same sex
they have similar physical and mental characters as well blood group but not finger prints
Superfecundation: is fertilization of two ova produced in the same menstrual cycle by two spermatozoa depositted in separate acts of coitus.
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