Multiple pregnancy is a condition when more than one offspring develops in the uterus of a woman. Multiple pregnancies are of two types – identical and fraternal.

Identical or monozygotic offsprings develop from a single egg that has been fertilized by a single sperm. What happens in this case is that the newly formed zygote splits into two or more embryos during the very first stage of development. Though sharing of the placenta is quite common in the case of identical fetuses, chances of their sharing one amniotic sac are very less. Identical offsprings are usually of the same sex and blood type. Such children are usually mirror images of each other; thus, when one child is right handed the other is left-handed.

Fraternal multiple pregnancies are a result of the fertilization of separate eggs by separate sperms. The different fraternal fetuses are fed by different placentas and are encapsulated in different amniotic sacs. Fraternal offsprings can be of different sexes and have different blood types. Appearance wise they may have some similarities (just like most siblings), yet are certainly not mirror images of each other.

Multiple pregnancies result from a number of different causes. Cases of multiple pregnancies are common among non-Hispanic (white or colored) women in the age group 35 – 45. Women who have already had a multiple pregnancy (fraternal) runs the risk of having another multiple pregnancy. Having a family history of fraternal twins or triplets or more may also be the reason behind your multiple pregnancy. Sometimes, infertility treatments such as the use of fertility drugs and/or Assisted Reproductive Technology (ART) to transfer multiple embryos directly into the uterus also increase your chances of having multiple pregnancy.

Multiple pregnancies are considered high-risk as they lead to multiple complications for the mother as well as the developing embryos. Miscarriage, premature birth, birth defects, genetic disorders, after birth complications, etc. are common with multiple pregnancies.

Tags: Fraternal, Identical, Multiple Pregnancy

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