By: Rachael Rettner, MyHealthNewsDaily Staff Writer
Published: 07/16/2012 09:05 AM EDT on MyHealthNewsDaily

Children conceived through use of fertility drugs may not grow quite as tall as other kids, a new study from Australia suggests.

In the study, boys whose mothers used fertility drugs were on average 1 inch (3 centimeters) shorter at ages 3 to 10, compared with boys of mothers who did not use the drugs.

While girls whose mothers who used fertility drugs also tended to be shorter than other kids, the findings were not as strong and could have been due to chance.

It's possible it wasn't the drugs, but something related to the parent's fertility problems that influenced the children's height, but the researchers found this was not the case. Children whose parents who used fertility drugs were shorter than children whose parents who had trouble having kids, but eventually conceived without taking fertility drugs.

The results were unexpected, the researchers said. Previous studies have found that children conceived using in vitro fertilization, which also uses fertility drugs, are taller than naturally-conceived children.

Because they study was small, further research is needed to confirm the findings. Additional studies are also needed to see whether the height difference persists into adulthood, the researchers said.

Other experts are not convinced by the findings. Dr. Avner Hershlag, chief of the Center For Human Reproduction at the North Shore Long Island Jewish Health System in Manhasset, N.Y., urged women considering fertility treatment not to resist treatment because of this study's results. "There is not solid evidence right now" of the link between fertility drug use and short stature in children, Hershlag said.

Effects of fertility drugs

While several studies have examined the effects of fertility treatments such as in vitro fertilization on children, few studies have examined the effects of fertility drug use alone.

In the new study, Wayne Cut?eld, of the University of Auckland, and colleagues analyzed information from 84 children whose mothers underwent ovarian stimulation with fertility drugs. They compared this group with 214 children whose parents were fertile and conceived naturally, and 54 children whose parents took more than 12 months to conceive, but eventually did so without treatments.

The average age of children in the study was 7.5.

The link between a shorter stature in children and use of fertility drugs held even after the researchers took into account factors that affect the height of children, such as the height and weight of the parents.

It's possible that ovarian stimulation with fertility drugs leads to alterations in certain genes in the embryo that result in developmental changes, the researchers said.

Complex trait

However, height is a very complex trait, and is influenced by many factors, including the environment a child grows up in, and the food he or she eats, Hershlag said.

"To me, that would be much more important than a drug given before conception," Hershlag said.

The researchers tried to account for family factors that could influence height by limiting their study to children of European descent, from families living in high socioeconomic communities. But Hershlag pointed out even siblings from the same family have different heights.

In addition, mothers in the study received different fertility treatments — some received the oral drug clomiphene, other received injections of follicle-stimulating hormone, and some received both treatments at once. This "hodgepodge" of treatments makes it hard to draw firm conclusions from the study, Hershlag said.

The study was published online July 9 in the journal Human Reproduction.

Pass it on:  In a new study from Australia, boys whose mothers used fertility drugs were about one inch shorter than boys whose mothers did not use fertility drugs.

Follow Rachael Rettner on Twitter @RachaelRettner,or MyHealthNewsDaily @MyHealth_MHND. We're also on Facebook & Google+.

Copyright 2012 MyHealthNewsDaily, a TechMediaNetwork company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

Also on HuffPost:

Loading Slideshow...
  • Alien Hand Syndrome

    Also sometimes referred to as the Dr. Strangelove Syndrome, this condition causes a patient's hand to <a href="http://health.howstuffworks.com/diseases-conditions/rare/alien-hand.htm" target="_hplink">take on</a> a life of its own and act on its own accord.

  • Riley-Day Syndrome

    Patients with this condition are often <a href="http://www.nlm.nih.gov/medlineplus/ency/article/001387.htm" target="_hplink">unable</a> to feel any pain, which can prove dangerous should they ever get injured.

  • Cotard's Syndrome

    An individual's <a href="http://www.ncbi.nlm.nih.gov/pubmed/12011289" target="_hplink">belief</a> that he or she is dead despite those around them saying they are not. Some report also believing they do not exist at all.

  • Apotemnophilia

    The <a href="http://cbc.ucsd.edu/pdf/apotem.pdf" target="_hplink">desire</a> of an individual to amputate a perfectly-healthy limb.

  • Alice in Wonderland Syndrome

    Patients with this condition <a href="http://www.aiws.info/symptoms" target="_hplink">report</a> experiencing distorted body proportion: certain body parts -- often the head and hands -- are larger than they should be.

  • Prosopagnosia

    Sometimes called "face-blindness," this condition <a href="http://www.faceblind.org/research/" target="_hplink">renders</a> individuals unable to recognize faces -- even those of the people they love or encounter on a regular basis.

  • Capgras Delusion

    The belief that an acquaintance, or even someone an individual knows very well, is <a href="http://www.npr.org/templates/story/story.php?storyId=124745692" target="_hplink">actually</a> an identical-looking imposter.