In preparing for fertility preservation, cancer fighters may worry about the risks of fertility preservation on the health of their future children. Fertility techniques, such as in vitro fertilization (IVF), produced more than a million babies over the past 30 years. As such, it is important to know whether egg banking , embryo banking, or other forms of fertility preservation cause birth defects in children ranging from cleft palate to neurodevelopmental disorders.
Studies do report that congenital malformations and birth defects increase slightly in couples using infertility treatments. Two other issues may be at play in these cases. First, parental factors affect the likelihood of birth defects. A Swedish study found that babies born to infertile couples (those who failed to get pregnant within a year of trying) had higher rates of congenital malformations, whether or not they used assisted reproductive technologies. This suggests that parental background may play a greater role than infertility treatment in the risk of childhood birth defects.
In addition, couples using fertility treatments often give birth to two or more children at one time. Multiple births in one pregnancy are associated with low birth weight and increased risks for growth problems. Some studies that find a rise in birth defects after infertility treatment also determine that these risks are minimized or eliminated when only one baby is born from each pregnancy. (Interestingly, there is a correlation between mandated health insurance coverage for infertility treatment and birth number that I will discuss at a later date).
There is evidence that infertility treatment may increase the risk of specific types of genetic diseases, called imprinting disorders. Some genes are expressed in a parental-specific manner. For example, a child may express the copy of a gene that they received from their mother but not their father. If, for some reason, the paternal gene is expressed, the child may develop abnormally. Some of the most well-know imprinting disorders are Beckwith-Wiedmann and Angelman syndromes, which normally occur in one out of every 10,000-20,000 children. While some studies did not find an increased risk of imprinting disorders after assisted reproductive technologies, others estimate that the risk may be as high as 4 times the risk in the general population. Further investigation is still ongoing to determine the likelihood of these disorders after fertility preservation and to find whether some techniques have higher risks than others.
Overall, birth defects occur in just under 2% of all births conceived naturally. When using fertility treatments such as IVF, this number increases to about 3%. Cancer survivors who understand the risks can also do their part in making the healthiest baby possible after fertility preservation, such as getting appropriate prenatal care and medical advice.