Fertility Treatments Send Multiple Births Soaring
Women under 35 have a better than 60 percent chance of twins or more
THURSDAY, Feb. 7, 2002 (HealthDayNews) -- Increasing numbers of couples are turning to assisted fertility therapies that up their odds of having multiple births, a government report released today says.
The trend has stirred concern among some reproduction experts because there's growing evidence that shows that babies born as a result of fertility treatments run a higher risk of potentially severe neurological problems.
The number of assisted reproductive treatments jumped 27 percent between 1996 and 1998, to nearly 81,900, according to the Centers for Disease Control and Prevention (CDC) report. The result: 28,873 babies, of whom 56 percent were twins, triplets or even "higher-order multiples."
The normal rate of multiple births in the United States in 1998 was 3 percent, health officials say. But for women under 35, the threshold of prime fertility, the rate of multiple pregnancies with in vitro fertilization treatments hit 62 percent in 1998.
Other figures available on the CDC's Web site indicate the trend of assisted fertility procedures continued to rise in 1999, topping 86,800, resulting in 30,185 babies, the agency says. California led all states with 10,615 attempts in 1998, followed by New York (8,689), Massachusetts (7,236), Illinois (5,145), and New Jersey (5,105).
Massachusetts, with a population of about 6.4 million, owes its place on the top five list to its generous insurance coverage of in vitro fertilization procedures, says Bruce Cohen, an epidemiologist who tracks birth statistics for the state's Department of Public Health.
At the same time, there's not so good news for the multiple birth set. The surge in the brith rate has alarmed reproduction experts, according to the latest report in The Lancet, a British medical publication. Mounting evidence shows that babies born through assisted reproductive technology are at an increased risk of potentially severe neurological defects, such as cerebral palsy and mental retardation. The risk is particularly significant for multiple-birth babies, experts say, who are more prone to being premature and underweight when coming from a crowded womb.
Carrying "multiples" also imperils women, who are at greater risk of bleeding and cesarean section surgery than they are during single-baby pregnancies.
The CDC reports that in 2000, thanks to the growing interest in fertility drugs, the rate of triplets, quadruplets and other "high-order multiple births" among U.S. women has risen more than four-fold since 1980. The increase has been most dramatic for women in the 35 to 39 year old age bracket, for whom the rate of such deliveries rose nearly 10-fold between 1980 and 1997.
Meredith Reynolds, a CDC epidemiologist and a co-author of the new study, says the agency considers the spike in multiple births a "public health issue." But the CDC doesn't make policy statements about "clinical practice," which, in this case, involves the number of embryos fertility doctors should transfer into women to maximize their odds of a successful procedure.
Rather, the CDC leaves those decisions up to clinical bodies, such as the Society for Assisted Reproductive Technology (SART) and the American Society for Reproductive Medicine (ASRM). However, Reynolds adds, "We encourage patients to have good information about how multiple embryo transfer can affect their risk" of delivering prematurely or suffering harm related to pregnancy.
Responding to the rise in multiple pregnancies associated with in vitro fertilization, ASRM in 1999 revised its practice guidelines to reduce the number of embryos transferred in an assisted reproduction procedure. The association now calls for only two fertilized eggs to be transferred into women with the best odds of becoming pregnant. That number rises to three for women with above average chances, four for those with average odds, and five for those with the worst prognosis -- typically women over 40 with a history of failed in vitro attempts.
Dr. Howard Jones, Jr., a noted fertility specialist at Eastern Virginia Medical School in Norfolk, says assisted reproductive techniques are just part of the problem of soaring twin and triplet pregnancies. Fertility drugs that stimulate ovaries are also causing the number of multiple births to jump, says Jones, founder of the Jones Institute for Reproductive Medicine.
And while guidelines for clinics help, they, too, are just half the equation. "It isn't only the doctors, it's the patients who are pressing for babies. It's a mutual situation," Jones says.
Underscoring the growing concern over multiple births and in vitro fertilization, Swedish researchers report in the latest issue of The Lancet that babies born through assisted reproductive techniques are roughly three times as likely as naturally conceived children to develop cerebral palsy. The risk of the disorder is even greater for multiple-birth babies.
Babies conceived through assisted reproductive techniques had about four times the normal rate of developmental delays, says Dr. Bo Strömberg, a pediatrician at University Children's Hospital in Uppsala and lead author of the study. Strömberg says many of those problems will likely prove to be cerebral palsy, mental retardation and other serious disorders that become apparent as the child ages.
"We can't guarantee that we wouldn't find more [neurological] disorders later in life because they aren't really old enough to get the diagnosis," he says. Roughly 60 percent of the 5,680 assisted reproductive technique children in the study were four years of age or younger.
Strömberg's group blames most of the neurological damage associated with the procedures on the high proportion of twins and other multiples, and the accompanying complications of underweight and premature deliveries. As a result, they conclude, couples should be discouraged from seeking to carry more than one embryo at a time.
However, Strömberg admits such a policy is unlikely to become widespread until in vitro fertility techniques become more efficient, since the cost of each successful attempt would skyrocket.
On the other hand, he says, "If you have a child with severe brain damage or severe [cerebral palsy], that child will live for years and he or she will cost quite a lot of money to society and have a great impact on the specific family."
Some parents may be willing to accept worse odds and higher costs, as long as they get a chance to conceive.
Lenore Skenazy is a columnist at the New York Daily News who has had two children through in vitro fertilization. In each case her doctors transferred five embryos, resulting in one child both times. But Skenazy says she and her husband would have gone ahead with the procedures even if they'd had to do it an embryo at a time.
"We were willing to do anything, if that's the only way it was available," she says.
What to Do: For a statistical look at assisted reproduction in America, try the CDC's Division of Reproductive Health. For more on assisted reproduction, visit the Society for Assisted Reproductive Technology, or the National Infertility Association.