Multiple births have increased during the 1980s and 1990s. Twin births rose more than 70 percent and “super twins”–births involving three or more babies–more than quadrupled. Today, you can go to nearly any elementary school classroom and see children from multiple births.
Some of this increase can be linked to having children later in life. After the age of 35, a woman becomes more likely to have a multiple birth and she may be more likely to require help getting pregnant. In addition, the number one reason for multiple births, 53%, is the use of fertility drugs and assisted reproductive technology such as in vitro fertilization.
For women with a normal menstrual cycle but low fertility, ability to become pregnant, drugs such as Clomiphene, Pergonal, Repronex, Gonal-F, Bravelle and Follistum can be used to release more than one egg during a reproductive cycle, improving the odds of fertilization through intercourse. As a result of this method, 15 to 20 percent of pregnancies result in twins and 5 percent in triplets or more.
For women who have greater difficulty becoming pregnant, in vitro fertilization may be used. In this method, the woman is given fertility drugs to produce multiple eggs, but these eggs are fertilized in a laboratory and the embryos are then placed back in her uterus. To increase the chances of success, several of the embryos are placed in the uterus on the theory that only the best will survive. This results in an increased chance for multiple births. According to the Centers for Disease Control, the multiple pregnancy rate for women using assisted reproductive technology is 36.2 percent.
Most couples seeking fertility treatment are aware of this possible outcome, and many actually want it. According to one 2004 survey, 20 percent of women stated that a multiple birth was what they considered an ideal result of fertility treatment. However, fewer than half of the people who responded fully understood the risks and complications associated with a multiple birth.
The complications begin even before birth. For a woman carrying twins or super-twins, morning sickness and vomiting are likely to come earlier and be more severe. Other problems that can occur with pregnancy, such as anemia (low iron), preeclampsia (high blood pressure, swelling and large amounts of protein in the urine) and gestational diabetes (diabetes during pregnancy), are more likely with multiple pregnancies.
Many of the health problems of multiple birth children come from the fact that they are likely to be premature (too early) and born with a low birth weight. With weakened lungs and neurological systems, they are at increased risk of cerebral palsy, blindness and other developmental and medical problems. In one study of 165 multiple birth babies, 149 required neonatal intensive care (NICU).
Over the past decade, several actions have been taken to try to reduce the number of multiple births (and the resulting medical complications) associated with fertility treatment. One way is to decrease the number of embryos transferred during in vitro fertilization. Some countries have mandated the transfer of single embryos only. In the United States, 2004 practice guidelines recommended that most women consider using only two embryos for transfer. This may be a result of clinics having learned new techniques that improve embryo quality and the chance of successful implantation.
Couples who have spent considerable effort and expense getting pregnant in the first place may think they desire a ready-made family. They should understand that such an attitude places their children and themselves at too much risk.
Written By: Kerri Musselman, Pharm.D.
