Fertility Treatment Birth Defect Rates Dropped in Recent Years: Study

The rate of children born with birth defects after fertility treatments appears to be dropping, and the kinds of treatment used seems to have little effect, according to the findings of new research. 

Australian researchers published a new study on assisted reproductive technology (ART) and birth defects in this month’s edition of the Obstetrics & Gynecology medical journal, indicating that the risk of birth defects from fertility treatments like in vitro fertilization (IFV), intracytoplasmic sperm injection (ICSI) and the use of Clomid has dropped over the last several years and is approaching the same level of risk as non-assisted reproduction.

Researchers conducted a retrospective cohort study using data from several registries that identified ART and non-ART births among about 214,000 pregnancies. They found that from 1994 to 2002, the rate of fertility treatment birth defects dropped from 11 percent to about 7.5 percent. Birth defects seen among pregnancies that did not involve fertility treatments stayed steady over the period, at just over 5%.

Prior research has found that from 1986 to 2002, there was a 35% increased risk of birth defects among babies born to women who underwent IVF treatment, a 72% increased risk with ICSI and a 300% risk of Clomid birth defects. The latest study did not find an appreciable difference between methods of fertility treatment, indicating that in recent years there was a 32% increased risk for all ART-pregnancies to result in a birth defect diagnosis by age 6.

“Assisted reproductive technology is a rapidly changing field and there have been many changes in clinical practice over time,” the researchers concluded. “Although we cannot explain this decrease with the data available, changes to clinical practice may be largely responsible with improved culture media and more optimal culture conditions leading to the transfer of ‘healthier’ embryos.”

Determining the true cause of birth defects in children conceived through assisted means is often difficult. For years, researchers have been trying to determine whether side effects of Clomid may increase the risk of birth defects, particularly neural tube defects (NTDs).

The FDA has received hundreds of post-marketing reports of birth defects after Clomid use since it was first approved in 1972. Some studies suggest the drug may as much as tripled the risk of birth defects when compared to women who conceived normally. However a number of other studies have found weaker or no associations.

Neural tube birth defects occur when the neural tube does not close completely, leaving an opening in the spinal cord or brain. This could result in spina bifida, anencephaly, as well as others birth defects.