Children born through in-vitro fertilization are at higher risk of having congenital defects, especially those related to eyes, heart and reproductive organs, a new study says.

The study was based on the data available of more than 50,000 births that occurred between 2006 and 2007 in California. About 4,800 of the babies born during the study period were born after fertility treatments or artificial insemination.

Researchers found that around 3,460 infants had some form of congenital defect. Babies born after in-vitro fertility treatment had higher risk of having congenital defects (9 percent higher) than babies that were conceived naturally (6.6 percent).

"Our findings included a significant association between the use of assisted reproductive technology, such as certain types of in vitro fertilization, and an increased risk of birth defects," said study author Dr. Lorraine Kelley-Quon, a general surgery resident at Ronald Reagan UCLA Medical Center, and lead author of the study.

According to Centers for Disease Control and Prevention (CDC), more than 1 percent of all infants born in the U.S. every year are conceived using ART.

Previous studies have shown that Infants conceived with Assisted Reproductive Technology are 2 to 4 times more likely to have certain type of birth defects than children conceived naturally. Typically the risks are due to multiple births as 25% of all pregnancies after IVF are twin pregnancies, 40% of babies born after ART are born as part of a twin pair.

"For parents considering in vitro fertilization or other forms of assisted reproductive technology, it is important that they understand and discuss with their doctor the potential risks of the procedure before making a decision," said Kelley-Quon.

The study was presented at the American Academy of Pediatrics (AAP) National Conference and Exhibition in New Orleans.

"Keep in mind that women with a history of infertility who do not undergo treatment also have a higher rate of pregnancy complications, so it may be something about the infertile population. It's difficult to know how much of it is related to the treatment, and how much is related to the group [of women] itself," said Dr. Lynn Westphal, associate professor in obstetrics and gynecology at the Stanford School of Medicine, reports The Huffington Post. Westphal wasn't involved in the present study.

Earlier study from Denmark published in 2006 said that the birth defects seen in babies born after ART may be related to hormonal treatment as well as the underlying infertility of the mother.