By Liza Mundy
Tuesday, June 5, 2007
The human womb is, ideally, a single-occupancy dwelling. One baby at a time is what women's bodies are marvelously calibrated to conceive and carry. One baby has lots of room for brain growth and organ development; one baby is (relatively) easy to deliver; one baby will usually have at least nine months of close parental bonding before another sibling possibly comes along.
Yet in the past 30 years, this country has experienced a stunning escalation in multiple births. The number of babies born as triplets, quadruplets or even more rose from about 900 in 1972 to 7,275 in 2004. That same year, the highest number of twins ever were born -- 132,000, nearly double the number born in 1980. Not coincidentally, there has also been a rise in premature births, infants born with low birth weights and disorders -- such as cerebral palsy -- that can occur when a premature baby's brain is insufficiently developed.
In the debate over federal funding for embryonic stem cell research, these facts need to be talked about. The broad U.S. ban on embryo research funding is one major undiscussed cause of our epidemic of multiple births. We need to consider embryo research as something important to the health of mothers and infants.
One factor among several in the rise in multiple births is in vitro fertilization, the popularity of which has soared. This is not surprising, since one in seven couples struggles with infertility. There are now 50,000 children born in the United States every year through IVF conception. More than half enter the world as part of a set.
That's because doctors in the nation's 400 IVF clinics routinely transfer two, three or more embryos into a woman's uterus at a time. They do this because they have no reliable way of telling which embryo has the crucial ability to develop into a fetus.
Since the mid-1970s, when IVF science was getting started, there has been an effective U.S. ban on funding for embryo research. At first a series of presidential commissions debated the ethics while postponing a decision; a board was created to approve research requests but was quickly disbanded. Scientists could apply for funding, but there was no one to apply to.
In 1996 a law known as the Dickey-Wicker Amendment took effect prohibiting funding research involving the creation or destruction of embryos. The provision is regularly passed as part of the Department of Health and Human Services appropriations bill. It has become a conservative touchstone.
The upshot is that scientists who receive federal funding -- and most good scientists do -- cannot use any part of it, even indirectly, to study the embryos that IVF creates so as to learn how to better assess their viability. "There is so much we do not know about the human embryo that we need to," said scientist James Trimarchi. "The truth is, we really don't know anything."
Many patients are happy to embrace the prospect of multiples, welcoming an instant multi-child family. But the stats are harsh: 50 percent of twins and 90 percent of triplets are born prematurely. Now one in eight U.S. infants is born at least three weeks early, according to a 2006 report by the Institute of Medicine. The preterm delivery rate has risen more than 30 percent since 1981. Twins are six times more likely to suffer from cerebral palsy than are singletons, triplets 20 times more. Infant mortality -- death in the first year -- is substantially higher in multiple births. One study found that at least one disabled child was produced in 7.4 percent of twin pregnancies, 21.6 percent of triplet pregnancies and 50 percent of quadruplet pregnancies.
And don't forget about the mothers. Among women pregnant with twins, the risks of post-partum hemorrhage and infection are doubled, the risk of death quadrupled. A woman pregnant with twins or triplets is more susceptible to the most dreaded complications of pregnancy, including preeclampsia.
Also, thanks to the ban, little is known about the health of IVF singletons. In the fall of 2005, a major conference was held by the National Institute of Child Health and Human Development to discuss troubling studies that suggested higher rates of complications and even birth defects among IVF children. There, U.S. scientists acknowledged that there is much they don't know, including whether embryos are affected by the media in which they are cultured, and the long-term impact of the increasingly invasive lab techniques that IVF now often involves.
Yet few people are talking about the larger issue of embryo research. The debate is only about stem cells. Congress is expected to hand the White House a bill this week authorizing funding for embryonic stem cell research using excess IVF embryos, with the hope that research on these three-day-old fertilized eggs might yield cures for afflictions such as diabetes and spinal cord injury. The president is expected to veto the bill. Polls show a majority of Americans want stem cell research to go forward, so sooner or later, it will. But isn't it time to rethink the broader ban?
Children are born every day whose health and well-being are permanently affected by the funding ban for embryo research. It is puzzling that no advocate has arisen willing to take it on in the name of public health. In England, state-licensed research on IVF embryos is permitted for 14 days after their creation. This limit seems reasonable and worth emulating. Embryos do deserve special moral status. But so does the other group that lacks a voice in this debate: children who owe their lives -- and perhaps their afflictions -- to the science that made them.
Liza Mundy, a reporter for The Post, is the author of "Everything Conceivable: How Assisted Reproduction is Changing Men, Women, and the World."