Multiple Pregnancy: The Dilemma
by: Christo Zouves, MD
Website: http://www.goivf.com

 

Multiple pregnancy in the United States from 1980 through 1997 showed a dramatic increase with twins increasing 52%, triplets 142%, quadruplets 123%, and quintuplets 98%. There is a very high price to pay for this increase, not only the cost of neonatal care for premature babies and ongoing care for children with handicaps, but also the increase health effects on women carrying large order multiple pregnancies which increase all the complications of pregnancy including high blood pressure, diabetes, cesarean section, and even maternal demise.

Why such a dramatic increase in multiple pregnancy? Twenty percent of the increase is due to women postponing childbearing and the fact that older women are more likely to have twins and triplets with spontaneous pregnancy.

Eighty percent of the increase is due to the use of fertility medications with half of this being due to fertility medications being given without in vitro fertilization and the other half due to in vitro fertilization with transfer of multiple embryos to the uterus.

Short of banning the use of fertility medications, it is very difficult to control the risk of multiple pregnancy when fertility drugs are given without IVF.

Within IVF, it is theoretically possible to limit the number of embryos that are transferred and in some countries there is legislation that controls this, in others there are voluntary guidelines and in others no guidelines at all. In the Unites States, there are a number of factors which drive the risk of multiple pregnancy with IVF. The desire of parents to have children especially when childbearing has been delayed often makes having a multiple pregnancy seem like a very distinct advantage. The lack of insurance help puts most of the financial burden on couples needing IVF also forcing them to seek IVF treatment later, when the age of the egg makes success less likely than at an earlier age.

Legislating the number of embryos for transfer would significantly disenfranchise certain patients or couples whose individual circumstances require more aggressive transfer, for instance, older patients using their own eggs or patients with genetic or immunological problems which decrease the implantation rate per embryo.

Strategies exist to try and limit the risk of multiple pregnancy, while maintaining high rates of success; these include growing the embryos to the blastocyst stage when the egg provider is under 35 and when there are more than eight or ten fertilized eggs available. The downside of holding the embryos for two days longer in the laboratory, relates to batch-to-batch variation in the quality of the media that may negatively affect embryo quality. Patients with recurrent loss or recurrent failed cycles should be evaluated for implantation factors which can be corrected thereby preventing the need to transfer large numbers of embryos merely because of previous failed IVF.

The availability of pre-implantation genetic diagnosis (PGD) will also allow the selection of embryos that are genetically normal before the embryo transfer, thereby avoiding the transfer of a large number of embryos in order overcome a known increase in the expected number of abnormal embryos. identify the risk of multiple pregnancy for a particular couple, explain the risks associated with carrying a multiple pregnancy especially more than twins, and to discuss before the transfer the alternative of selective reduction for reasons of medical safety. All IVF practitioners look forward to the day when a single normal embryo can be transferred after optimizing implantation factors and for this transfer to result in the birth of a single healthy infant. The allocation of federal funds for IVF and embryo research would certainly make single embryo transfers a reality sooner.