It is true that fertility treatment increases the risk of having a multiple pregnancy. However, most twins result from spontaneous conceptions -- couples who conceive on their own! Triplets or more are a different story; approximately 15% of triplet and 7% of quadruplet pregnancies were conceived spontaneously.
The increased risk of a multiple pregnancy during fertility treatment is a result of the medication used to cause or boost ovulation. Approximately 5-8% of pregnancies conceived with the use of clomiphene citrate, an oral fertility drug, are twins. Triplets or greater occur very infrequently. Use of gonadotropins, which are injectable fertility drugs, result in twins about 15% of the time and more than twins in about 3% of cycles.
The risk of multiple pregnancies is also increased with IVF. Younger women are more likely to have twins than those who are somewhat older. For example, in this country approximately one third of women under the age of 35 undergoing IVF will have twins, where as less than 10% of women over 42 will have twins. The risk of triplets is low in all age groups because most women under 35 will have only one or two embryos transferred.
Though fertility treatment generally increases the risk of a multiple pregnancy, the majority of individuals and couples will have a single baby!
My side: I think the number one cause of litters is irresponsible doctors. Doctors that prescribe Clomid like candy, or the extreme - Octomom's doc who chose to transfer 6 embryos into a healthy young woman with previous IVF success. Twins are common, but that is because most women choose to transfer at least two embryos. Why? Because IVF is an expensive procedure and women want to give each cycle the best chance possible of at least one baby. If insurance covered it, there would be fewer twins. In fact, with fewer multiples, fewer preemies, and less disability, we all pay less. So when is infertility going to be covered like other diseases and disorders?
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