In Vitro Linked to Rare Bladder Defects
Disorder Among Conditions Linked to Babies Born Through In Vitro Fertilization
March 19, 2003 - More than 1 million babies worldwide have been born through in vitro fertilization, and the overwhelming majority are perfectly healthy. But recent studies suggest the popular 25-year-old technology may increase the risk of various rare birth defects and medical problems.
The latest: A finding by Johns Hopkins researchers that in vitro-conceived babies may be seven times more likely to be have rare urological birth defects -- including having their bladders outside of their bodies.
While this exstrophy-epispadias complex is extremely rare -- affecting only three per 100,000 births -- researchers at the Johns Hopkins Children's Center noticed that among the 78 patients treated for it over a four-year period, four were conceived through in vitro fertilization. The Hopkins facility treats about one in seven of all American children with this birth defect.
"Considering how rare bladder exstrophy is, when you see four in vitro fertilization children with it over a short period of time, it makes you take notice," says John P. Gearhart, MD, director of pediatric urology. "I mentioned this observation to some colleagues in Europe, and they said, 'We've seen the same thing.'" Both teams of researchers are now collaborating on a large study.
Bladder exstrophy is the most common birth defect of this complex, characterized by the bladder protruding through the abdominal wall -- being exposed outside the body. Another bladder defect allows the inner lining of this hollow organ to be exposed. . Other defects affect pelvic bones, the urethra, and genitals. These birth defects can be detected with a high-level ultrasound during pregnancy -- a procedure Gearhart recommends for all women with in vitro-conceived pregnancies.
"Exstrosphy babies are good babies -- they have good lungs, good spines, good heads. They just happen to be born with their bladder on the outside. But it's fixed with surgery and they go on with their lives," Gearhart tells WebMD. "We continue to encourage people who are childless to have in vitro pregnancy, but take that extra bit of caution, that extra bit of care, and get a high-level ultrasound during pregnancy performed by a trained neonatologist to look for this condition. This should not discourage couples from having in vitro fertilization."
But his finding, published in the April issue of the Journal of Urology, is the latest discouraging news associating in vitro fertilization to a host of medical problems. In January, Dutch researchers reported in The Lancet that in vitro fertilization babies are up to seven times more likely to have a rare cancer of the retina that affects about one in 17,000 births. And last March, two studies in The New England Journal of Medicine suggested that low birth weight and defects such as Down syndrome were twice as high for babies born to mothers who undergo either in vitro fertilization or intracytoplasmic sperm injection (ICSI). And just one month earlier, another Lancet study linked in vitro fertilization with higher rates of various brain disorders, including cerebral palsy.