Written by: Heather Helmendach, Legal Assistant
Law Offices of Thomas J. Lamb, P.A
On April 3, 2017, updated results from the National Birth Defects Prevention Study (NBDPS) were released and published in the article "Maternal Antihypertensive Medication Use and Congenital Heart Defects" (Abstract only).
This study found that there was a statistically significant association between β-blocker use in pregnant women and fetal congenital heart defects.
The most commonly used β-blockers in the study were Trandate (labetalol), Tenormin (atenolol), Hemangeol / Inderal / Innopran (propranolol), and Lopressor / Toprol (metoprolol).
The researcher's findings and specific odds ratios pertaining to an increased risk of congenital heart defects are described in the excerpt from the Abstract, below:
We observed increased risk of 4 CHD phenotypes, regardless of antihypertensive medication class reported: coarctation of the aorta (2.50 [1.52–4.11]), pulmonary valve stenosis (2.19 [1.44–3.34]), perimembranous ventricular septal defect (1.90 [1.09–3.31]), and secundum atrial septal defect (1.94 [1.36–2.79]).
Furthermore, researchers stated, "We calculated adjusted odds ratios [95% confidence intervals] to estimate the risk of specific CHDs associated with antihypertensive use during the month before conception through the third month of pregnancy, controlling for maternal age, race/ethnicity, body mass index, first trimester cigarette smoking, and NBDPS site" (emphasis added).
However, a recent JAMA Research Letter casts doubt on the sufficiency of these controls, claiming that statistic significance no longer exists "after adjusting for maternal age, maternal body mass index, and maternal comorbidities" (emphasis added).
While the authors of the letter acknowledge that "maternal β-blocker exposure was associated with significantly increased odds of fetal congenital cardiac anomalies," they attribute the association to possible confounding, stating "β-blocker exposure was not associated with increased risks of fetal congenital cardiac anomalies after adjustment for maternal comorbidities."
Of note, the research letter does point out that "these findings do not definitively rule out the possibility of fetal congenital defects in association with β-blocker use." More expansive research is needed before it can be definitively determined whether β-blockers are associated with fetal congenital heart defects when used by pregnant mothers.
We will continue to monitor the medical literature concerning the association with β-blockers and fetal congenital heart defects. Updated information will be added to this post as it becomes available.
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