NON-IDENTICAL

The twins have developed from 2 separate eggs and sperms. There are 2 waterbags and 2 placentas.
Each baby carried its own individual risks which in general is equal to the risks of a single baby. However this is multiplied by 2 in total for the mother.

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IDENTICAL

The twins have started from 1 egg 1 sperm embryo but divided into 2.
There is one placenta and 2 waterbags. Occasionally there can be even only 1 waterbag. Rarely the twins are conjoined.

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COMPLICATIONS

General Risks

Miscarriage 30%
Preterm birth 50% (birth < 37 weeks: palsy, eye/heart/lung/bowel complications and death in extreme prematurity < 27 weeks in Sabah)
Structural defects 4-8%
Intrauterine fetal growth restriction

Twin to twin transfusion (TTTS) occurs in 30% of identical twins as they share the placenta. Only 70% of these ill have at least one surviving baby the end.