December 7, 1989 -- Pearl Harbor Day -- is a day that Bill and Anne Connor will never forget.
It was the day their premature son, Daniel, finally was able to come home from the hospital after two months. He was one of the 28-week-old twins Anne, of West Deptford Township, N.J., gave birth to after receiving infertility treatments.
His sister, Jaclyn, had to remain in the hospital for four more days.
Their story is a familiar one in the United States. More than 12 percent of all babies born in 2004 were premature, according to a report released today by the prestigious Institute of Medicine in Washington.
The report estimates that each year there are 500,000 pre-term babies born, a 30 percent increase since the early 1980s.
Why? No one knows for sure, the IOM report said. The institute is calling for a "research agenda" to better understand how to predict and prevent such births.
However, the report also focuses on family situations similar to the Connors'. The use of infertility treatments often results in pregnancies with multiple babies, increasing the risk they will be born early.
About 10 percent of premature babies are conceived by infertility treatments, said Dr. Marie McCormick, a pediatrician and one of the committee members who helped author the IOM report.
"The human uterus wasn't designed to carry multiple pregnancies for 40 weeks [i.e.full term]," said Dr. William Gibbons, the president of the Society of Assisted Reproductive Technology and an infertility specialist in Baton Rouge, La.
Not only is prematurity the No. 1 cause of infant death, but premature babies are also more likely to have health problems, said Dr. Jennifer Howse, president of the March of Dimes.
About one-quarter of premature babies have permanent long-term health issues, including developmental delay, cerebral palsy, respiratory difficulties, heart abnormalities and visual and hearing impairments, Howse said. Caring for preterm babies also is expensive. In 2005, the nation spent more than $26 billion caring for preterm babies, including not only the cost of medical care but also the cost of special services after leaving the hospital and the lost productivity of parents.
The Connors' twins, Daniel and Jaclyn, had multiple health problems as infants, including lung problems, vision loss and a type of anemia that required blood transfusions. Jaclyn even required a liver transplant at 10 months of age after developing neonatal hepatitis.
While many of the factors that contribute to the rise in preterm births are unknown, fertility treatments are one area that can be clearly identified as a cause and can be changed, said McCormick, who is also a professor of Maternal and Child Health at the Harvard School of Public Health.
The report recommends that infertility doctors work to reduce the number of multiple births, transfer only one embryo during in vitro fertilization and restrict the use of hormones that cause women to ovulate more.
As advancements in treating infertility have been made, there is less need to implant so many embryos in the uterus during in vitro fertilization, Gibbons said.
His organization already has guidelines in place limiting the number of embryos that should be transferred during in vitro fertilization. Many infertility doctors and clinics are following these guidelines, he said.