Folate, the B vitamin, protects against malformations of the central nervous system early in pregnancy — if the pregnant woman has enough in her system. In the U.S., fortification of enriched cereal grain products has been mandated since 1998. Since that time, the incidence of so-called neural tube defects has indeed decreased. Canada also mandated folate fortification for the same reasons in 1998, and a new study in Circulation indicates that such fortification benefits babies' hearts as well as their nervous systems.
Dr. Shiliang Liu, from the Public Health Agency of Canada, in Ottawa, ON, Canada and colleagues analyzed records of nearly 6 million live births, stillbirths and late pregnancy terminations that occurred between 1990 and 2011 in Canada. By beginning their study before, and continuing it well beyond the onset of folate fortification, they were able to assess the differences in fetal heart malformations before and after the institution of folate fortification. Over the 22 years covered by the study, there were nearly 67,000 cases of various types of heart malformations. Overall, this amounted to a prevalence rate of 12.3 malformations per 1000 births.
The rates for most types of heart defects decreased after folate supplementation began. These included:
- conotruncal(1) defects decreased by 27 percent;
- coarctation of the aorta(2) by 23 percent;
- ventricular septal defects by 15 percent;
- atrial septal defects by 18 percent.
Severe non-conotruncal heart defects and other heart or circulatory system abnormalities did not decrease significantly.
Overall, congenital heart defects decreased by 11 percent — a modest effect. The authors noted that other factors such as older maternal age, prepregnancy diabetes mellitus, and preterm preeclampsia were also associated with population rates of CHDs.
Although the decreases in cardiac defects were modest, the fact that cardiac malformations are more common than the central nervous system defects that folate fortification was designed to ameliorate, indicates that such fortification can be considered to have additional benefits. Thus it behooves healthcare providers to continue to emphasize the importance of folate intake to women who plan to become pregnant so that fetal development can progress as normally as possible.
(1) Common types of conotruncal heart defects are truncus arteriosus, transposition of the great arteries, double outlet of the right ventricle, and tetralogy of Fallot.
(2) Coarctation of the aorta, also called aortic narrowing, is a congenital condition whereby the aorta is narrow, and the heart must work harder to pump blood through it to the body.