Do Fertility Treatments Increase Risk of Birth Injuries?
Assisted conception through fertility treatments (such as in vitro fertilization) has become increasingly common in the United States over the last 20 years. It is estimated that about 5% of births worldwide are now the result of fertility treatments and this rate is probably even higher in the U.S. and Western Europe. Although assisted reproductive treatments can be a blessing for couples unable to conceive naturally, a series of recent studies have established that fertility treatment significantly increases the risk of birth injuries such as cerebral palsy. This page will look at the common methods of assisted conception and examine the reasons why they result in higher rates of birth injury.Modern Fertility Treatments
Over the last 20-30 years there has been a drastic increase in the utilization of assisted reproductive therapies or fertility treatments in developed countries. This increase is attributable to numerous factors. First, the standard of living and educational level of women in developed countries such as the U.S. has advanced significantly and cultural views of women's roles have also changed. The net result of these changes is that more and more women are waiting longer to get married and/or have children. Older women have more trouble with fertility and, therefore, these cultural shifts created a higher economic demand for fertility treatments. The increased demand fueled the rapid development of new and improved reproductive technologies, which soon became much more affordable and widely available.
Now women or couples who need assistance to achieve pregnancy have a number of viable treatment options. The most commonly utilized fertility treatments today are:
- Ovulation Induction: ovulation induction (or ovarian stimulation) is probably the most commonly utilized fertility treatment. Around 40% of women with infertility have issues with ovulation (the release of an egg once a month). Ovulation induction basically stimulates a woman's ovaries with drugs prompting the release of multiple eggs in a single cycle, thereby increasing her chances of egg fertilization and pregnancy. Stimulation of the ovaries is usually done by prescribing the popular fertility drug Clomid (Clomiphene Citrate). Clomid works by manipulating hormone receptors in a woman's body.
- Intrauterine Insemination (IUI): Intrauterine insemination (IUI) (more commonly known as "artificial insemination") is another common assisted reproduction method used when Clomid or alone is not successful or not applicable. Semen samples are collected from the father and "washed" to increase the concentration of fully healthy sperm. The health sperm collection is then directly inserted into the woman's uterus right when she is ovulating. The technique is often done in combination with fertility drugs like Clomid.
- In Vitro Fertilization (IVF): In vitro fertilization (IVF) is the most involved type of assisted reproduction technique. Semen is collected and washed to isolate healthy sperm. The mother is given drugs to stimulate egg release and then several viable eggs are taken from the mother. Doctors then mix the sperm and eggs together in a laboratory dish. Then 1 or more of the fertilized eggs (embryos) are implanted directly back into the woman's uterus. Pregnancy will result only if the implanted embryos are accepted by the woman's body and implant into the lining of her uterus.
Between 1996 and 2010 results were published from a handful of different, independent studies examining the relationship between fertility treatments and increased risks of birth injuries. All of these studies reached essentially the same conclusion: babies that were conceived with the assistance of infertility treatments had a higher than normal risk of cerebral palsy and other birth injuries. One of the European studies, published in Human Reproduction, found that assisted reproduction babies were nearly 2 times more likely to be diagnosed with cerebral palsy compared to naturally conceived babies. The risk of other types of infant brain injuries during childbirth was also significantly higher with fertility treatment.
The study results indicated a very clear reason for this increased level of risk which is not related to the fertility drugs or techniques themselves. In fact, part of the reason fertility treatments increase the risk of birth injuries is because they are almost too effective. Modern scientific advances have made fertility treatments such as IVF so effective that they routinely result in multiples (twins, triplets, etc.). In fact, Canadian health officials recently reported that almost 40% of IVF pregnancies resulted in multiples (2 or more). This is problematic because cerebral palsy is 6 times more likely in twins and 9 times more likely to occur with triplets compared to individual babies. There are numerous reasons why the chances of cerebral palsy are much higher with twins and triplets. The most significant reason is that twins and triplets are much more likely to be born prematurely and premature birth is the leading risk factor for birth injuries such as cerebral palsy. Not only are all multiples more likely to be premature, twins and triplets conceived via IVF are even more likely to be preemies than their naturally conceived counterparts.
Aside from increasing the rates of multiples and the higher likelihood of premature birth, certain aspects of fertility treatments may have other detrimental effects on fetal development compared to natural conception. Additional studies are underway to further understand these factors.