Multiple birth

From Academic Kids

Missing image
Identical Triplet Sisters

A multiple birth results when more than one human baby is born from a single pregnancy.



The most common form of multiple birth is twins (two babies), but cases of triplets (three), quadruplets (four), quintuplets (five), sextuplets (six), septuplets (seven), octuplets (eight), and nonuplets (nine) have all been recorded with all siblings being born alive. There have been pregnancies — but no known instances of live births — of decaplets (ten), undecaplets (eleven) or duodecaplets (twelve).

There are two types of multiple births, fraternal and identical. Identical siblings arise where one egg is fertilised and the resulting zygote splits into more than one embryo. Identical siblings therefore have the same genetic material. Fraternal siblings result from the fertilisation and implantation of more than one egg, so fraternal siblings are not genetically identical.

Causes and frequency

Multiple births can occur either naturally (the woman ovulates multiple eggs or the fertilized egg splits into two) or as the result of infertility treatments (several embryos are usually implanted to compensate for their lower viability).

In general, twins occur naturally at approximately the rate of 1/89 of singleton births, triplets at 1/89 the rate of twin births, and so on (Hellin's Law). However, for reasons that are unknown, the older a woman is, the more likely she is to naturally have a multiple birth.

The number of multiple births has increased over the last decades. For example, in Canada, between 1979 and 1999, the number of multiple birth babies increased 35%. Much of the increase can probably attributed to the impact of fertility treatments, such as in vitro fertilisation. Younger patients who undergo treatment with fertility medication containing FSH followed by intrauterine insemination are at particular risk for multiple biths of higher order.

Certain factors appear to increase the likelihood that a woman will naturally conceive multiples. These factors include: mother's age (women over 35 are more likely to have multiples than younger women); mother's race (African women have a frequency of 16 fraternal twin pairs per 1,000 births; East Asian women have a frequency of 3 pairs of fraternal twins per 1,000 births; Caucasian women have a frequency of 8 pairs of fraternal twins per 1,000 births); mother's use of fertility drugs (approximately 35% of pregnancies arising through the use of fertility treatments such as IVF involve more than one child)

The increasing use of fertility drugs as well the increasing life expectancy for women have contributed to the rise in the rate of multiples over the last fifty years.


Recent increases over the last few years in the number of multiple births have also provoked concern over the risks to the fetus and also to the mother.

The greater the number of babies in a single pregnancy, the more likely they are to have a low birth weight, to be born prematurely and to consequently suffer medical problems. For example, in 1999, 53% of babies in multiple births were premature, compared to 7% of singletons. [1] ( There is also a higher rate of stillbirths for multiples than for singletons.

Virtually all obstetrical risks are increased for the mother during a pregnancy with multiples. As many multiple pregnancies today are the result of the use of fertility therapy, efforts are being made to reduce the risks of multiple pregnancy, specifically triplets or more, by limiting the number of embryos (embryo transfer) during IVF to 1 or 2. Also, methods are available to reduce the number of fetuses in a pregnancy with many (see fetal reduction).

Cultural aspects

Certain cultures consider multiple births a portent of either good or evil. A North Korean tradition that states that triplets are 'lucky' has led to the seizure of all sets of triplets born in North Korea, apparently out of leader Kim Jong Il's fear that one may overthrow him in the future.

List of famous multiple births

Fictional multiple births

See also

External links


  • "Korea's 'lucky' triplets seized," article in Herald Sun newspaper (Australia), March 30,

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