Multiples, which include conception and birth of two or more babies, occur in approximately one to two percent of naturally occurring pregnancies. For women undergoing fertility treatments, as many as one in three women will conceive multiples- with about five percent of those pregnancies consisting of higher-order multiples (three or more babies).
Over the years, in vitro fertilization (IVF) has developed a bad reputation for resulting in higher-order multiples. However, IVF techniques have improved over the past 20 years to reduce these risks. Fertility doctors are now often able to achieve positive results transferring only one or two embryos, thus dramatically reducing the risk of multiples due to IVF.
Fertility drugs, such as clomiphene citrate and injectable gonadotropins, have a higher risk of multiples. Used in conjunction with in vitro fertilization, intrauterine insemination (IUI) and timed intercourse, these fertility drugs stimulate the ovaries to cause multiple eggs to mature. Then, human chorionic gonadotropin (HCG) is administered to trigger follicles to release the eggs.
Understanding the risks to you and your babies when carrying multiples is important. Multiples are at a much greater risk of being born prematurely. When born, they may not be fully developed and are more susceptible to developmental challenges, illness and death. In addition to premature labor, mothers carrying multiples are more likely to suffer from high blood pressure, diabetes and anemia. There’s also a higher chance you will require a Cesarean section.
The risk of multiples due to fertility drugs is difficult to manage. Generally, your fertility doctor will prescribe low doses of the medication in an attempt to reduce the number of eggs developed and released. In addition, close monitoring of your cycle can help determine whether too many eggs are developing. Your fertility doctor may recommend skipping a cycle if there is a high risk of too many eggs being fertilized.
In the event three or more embryos implant, your fertility doctor may recommend selective reduction to decrease the risks to the mother and the remaining babies. Choosing to only allow one or two embryos to continue developing is difficult, and couples should speak with a counselor before making a decision.
