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ADELAIDE, May 8, 2012 ( – In a comprehensive study of the relative risk of birth defects among all forms of assisted reproductive technology (ART), researchers found the overall risk of any birth defect when using such technologies was 8.3 percent, compared to the significantly lower 5.8 percent in naturally conceived children.

The most common birth defects linked to ART included cleft palate, spina bifida, cerebral palsy and cardiovascular, musculoskeletal and gastrointestinal conditions.

“While [fertility] treatments appear quite safe, we cannot ignore that there are significant risks that require urgent investigation with additional ongoing studies,” said lead researcher Michael Davies, Associate Professor at the Robinson Institute of the University of Adelaide.


“The excess risk for IVF could be explained by patient characteristics, such as age or weight,” Davies pointed out. “In contrast, the risk for ICSI (Intracytoplasmic sperm injection) could not be explained by available factors.”

Comparing the birth defect rates among the various forms of assisted reproductive technology, the researchers reported ICSI resulted in the highest rate at 9.9 percent, followed by in vitro fertilization (IVF) at 7.2 percent.

ICSI involves the direct fertilization of one egg by the injection of only one sperm. IVF creates many human embryos by mixing ova and sperm in a petri dish.

In both forms of assisted reproductive technology the newly created human is then inserted into the womb of the mother.

An Australian study published in the New England Medical Journal in 2002 found 8.6 percent of infants conceived with intracytoplasmic sperm injection had a major birth defect diagnosed by one year of age, while infants conceived with in vitro fertilization had birth defect rate of 9.0 percent. That study reported a 4.2 percent birth defect rate for naturally conceived infants and concluded that “Infants conceived with use of intracytoplasmic sperm injection or in vitro fertilization have twice as high a risk of a major birth defect as naturally conceived infants.”

Professor Davies’ research team also studied the birth defect rate of women who used clomiphene citrate at home to stimulate ovulation. The easily available steroid is used by about 37,000 women in Australia each year, the report stated; it found that use of the drug triples the risk of birth defects.

“It is very commonly used as a first-line treatment for an ovulatory infertility, as it is considered to be safe, cheap and non-invasive,” explained Prof Davies.

“Although this finding was identified in a small subgroup, it is consistent with a large U.S. study from early 2011,” Davies said.

The study by Professor Davies and colleagues was published online May 5 in the New England Journal of Medicine.