Ken Lim

Effect of Folic Acid Food Fortification in Canada on Congenital Heart Disease Subtypes

Background: Previous studies have yielded inconsistent results for the effects of periconceptional multivitamins containing folic acid and of folic acid food fortification on congenital heart defects (CHDs). Methods: We carried out a population-based cohort study (N=5 901 701) of all live births and stillbirths (including late-pregnancy terminations) delivered at ≥20 weeks’ gestation in Canada (except Québec and Manitoba) from 1990 to 2011. CHD cases were diagnosed at birth and in infancy (n=72 591). We compared prevalence rates and temporal trends in CHD subtypes before and after 1998 (the year that fortification was mandated). An ecological study based on 22 calendar years, 14 geographic areas, and Poisson regression analysis was used to quantify the effect of folic acid food fortification on nonchromosomal CHD subtypes (n=66 980) after controlling for changes in maternal age, prepregnancy diabetes mellitus, preterm preeclampsia, multiple birth, and termination of pregnancy. Results: The overall birth prevalence rate of CHDs was 12.3 per 1000 total births. Rates of most CHD subtypes decreased between 1990 and 2011 except for atrial septal defects, which increased significantly. Folic acid food fortification was associated with lower rates of conotruncal defects (adjusted rate ratio [aRR], 0.73, 95% confidence interval [CI], 0.62–0.85), coarctation of the aorta (aRR, 0.77; 95% CI, 0.61–0.96), ventricular septal defects (aRR, 0.85; 95% CI, 0.75–0.96), and atrial septal defects (aRR, 0.82; 95% CI, 0.69–0.95) but not severe nonconotruncal heart defects (aRR, 0.81; 95% CI, 0.65–1.03) and other heart or circulatory system abnormalities (aRR, 0.98; 95% CI, 0.89–1.11). ConclusionS: The association between food fortification with folic acid and a reduction in the birth prevalence of specific CHDs provides modest evidence for additional benefit from this intervention.

Fetal Sex Determination and Disclosure

The Supreme Court of Canada (McInerney v. MacDonald 1992) concluded that a patient is entitled to examine and copy from his or her medical record all information the physician considered in administering advice or treatment.2 The physician must justify denying access to that record on the basis that doing so would not be in the patient’s best interest. On the basis of this ruling, it is legally difficult to defend nondisclosure. Disclosure of fetal sex upon request respects a woman’s rightful autonomy over personal health information. Those who oppose fetal sex determination and disclosure have concerns about risk for error, the time involved in making a determination of fetal sex, and that the information may lead women to abort pregnancies when the fetus is not the wanted sex. The risk for error is estimated to be less than 3%, but prospective parents should be made aware of this possibility with disclosure.3 There is no evidence that fetal sex determination during a complete obstetric ultrasound will extend the examination time.3 A small number of pregnant women may consider abortion when the fetus is the unwanted sex; however, this is best addressed by the health professionals who are providing care for these women. Diagnostic imaging units that prefer to maintain a policy of nondisclosure of fetal sex should include the information in their reports. This would allow the referring physicians or midwives to disclose the fetal sex at their patients’ request. In summary, SOGC recommends that fetal genitalia be examined as a part of the routine second trimester obstetric ultrasound and that this examination not be prolonged or repeated if no abnormalities are seen but sex determination is inconclusive. If fetal sex has been determined, a patient’s request for disclosure should be respected, either directly or in a report to the referring health professional.

Utilisation non médicale de l’échographie fœtale

La présente déclaration de principe commune a été rédigée par le comité d’imagerie diagnostique de la Société des obstétriciens et gynécologues du Canada, et le Groupe de travail sur l’échographie au point de service de l’Association canadienne des radiologistes, et approuvée par le comité exécutif et le Conseil de la Société des obstétriciens et gynécologues du Canada, et le conseil d’administration de l’Association canadienne des radiologistes.