Many of you have questions following this week’s report on a major study looking at the autism risk associated with different types of in vitro fertilization (IVF). Researchers found that most forms of IVF do not increase the risk of autism. They found a small increased risk only with procedures that involve surgical sperm retrieval, a treatment for male infertility. To answer the follow-up questions we’re hearing, we’ve tapped Alycia Halladay, Ph.D., Autism Speaks senior director of environmental and clinical sciences.
Why did Autism Speaks help fund this study?
Dr. Halladay: There’s been a lot of speculation about how IVF might affect a child’s development. For instance, researchers have looked at IVF and the risk of cerebral palsy and learning disabilities. Some of their studies did, in fact, associate IVF with increased risk for certain developmental disorders.
Along these lines, some have raised concerns about whether IVF might increase the risk of autism. Early research produced mixed results. Some studies suggested that IVF increased autism risk. Others found no such association. For these reasons, Autism Speaks funded this large study to help clarify the picture.
Because there are so many types of IVF procedures, we knew it would require a very large study sample – such as that in Sweden’s national health registry – to get that clear picture. In particular, this study allowed researchers to tease apart the risks associated with different IVF procedures.
Autism Speaks is interested in identifying risk factors because this allows researchers to study their biological mechanisms – and perhaps address them. We also want to identify children who might be at increased risk for developing autism – so that parents and physicians can monitor their early development and provide early intervention if needed.
What IVF procedures appear to increase autism risk?
Dr. Halladay: The great news is that this study found no associated autism risk with the vast majority of IVF procedures. The one exception was surgical sperm retrieval. Even there, the overall increased risk was modest and disappeared entirely when the researchers excluded pregnancies that resulted in preterm or multiple births (twins, triplets, etc.). We know, from previous research, that preterm and multiple births can carry an increased risk of autism regardless of whether they result from natural or IVF conception.
It all seems so complicated. When does IVF include surgical sperm retrieval and multiple-birth pregnancy?
Dr. Halladay: IVF is one of many types of assisted reproductive technologies. It involves retrieving eggs and sperm and fertilizing them “in-vitro” (basically, in a dish). Then the fertilized embryo is implanted in the womb for the pregnancy. Often times, IVF fertilization involves a procedure called intra-cytoplasmic sperm injection, or ICSI. A technician injects a sperm into the egg. Most commonly, the sperm comes from a man’s ejaculation. Sometimes, it has to be obtained surgically – most commonly after a vasectomy. This is called surgical sperm extraction or retrieval.
To further complicate things, embryos created through IVF can be implanted “fresh” –that is, when they’re a few days old. Or, they can be frozen in liquid nitrogen for later use. Freezing is commonly done when more embryos are created than can be implanted for a single pregnancy. The American Society for Reproductive Medicine has developed guidelines on how many embryos should be implanted at one time.
We’re considering IVF. What can we do with this new information on autism risk and surgical sperm extraction?
Dr. Halladay: You may want to share these finding with your doctor as part of a larger discussion about risks. If you are considering IVF with surgical sperm retrieval, you’ve probably been through rounds and rounds of testing and treatment. From my perspective, the modest risk of autism is outweighed by the enormous benefit of having a child. But talk with your doctor. He or she may have some advice specific to your situation. For instance, you might want to consider your family history of autism or the results of any genetic testing you may have had when you started fertility treatment.
Importantly, follow your doctor’s advice on maintaining a healthy pregnancy. Go to your prenatal appointments regularly, and take your prenatal vitamins.
Our new baby was born prematurely following IVF with surgical sperm retrieval. Now what?
Dr. Halladay: Your baby belongs to a group of children who, overall, have a modestly increased risk for autism. Knowing this, you and your child’s pediatrician will want to monitor your child’s development so you can be alert to possible early signs of autism. This will allow you to intervene early if warranted. This is powerful because we know that early intervention for autism can dramatically improve outcomes. So Learn the Signs, and enjoy your baby!
Our child has autism. Is it because we used IVF with surgical sperm retrieval?
Dr. Halladay: In no way does this research assign blame for causing autism. This merely identified one possible environmental factor that may modestly increases the risk that a child will develop autism. (Please see “Autism Risk vs. Cause” and “What do scientists mean when they talk about ‘environmental factors’ that cause autism?”) Decades of research suggest that many factors combine to tip brain development in the direction of autism. These almost always include a genetic predisposition.