The use of β-Blocker
in pregnancy does not increase the risk of fetal congenital cardiac anomalies after
adjusting for maternal co-morbidities says the results of a large population basedcohort study conducted by department of research and evaluation at Kaiser
Permanente Southern California.
The study
was reported as a research letter online April 17, 2017 in JAMA Internal
Medicine.
Lewei Duan and
colleagues from Kaiser Permanente, California note, “Beta-blockers are the most
commonly used class of medication for treating cardiac conditions in pregnant
women. Despite the common use of this class of medication, data that support
its safety are limited.”
“A recent
meta-analysis reported an association between beta-blocker exposure and fetal
congenital cardiovascular defects, raising a concern regarding potential
teratogenic effects of this class of medication.”
The authors identified
379,238 women through birth records who delivered at Kaiser Permanente, Southern
California through a period of 11 years (2003-2014). Of these, 4847 women
(1.3%) received β-Blocker during pregnancy as identified by pharmacy dispensing
records.
And, 2,628 (0.7%)
were exposed during the first trimester of pregnancy.
Most common beta-blockers were labetalol (n = 3357), atenolol
(n = 638), propranolol (n = 489) and metoprolol (n = 324). The most common
indication for prescribing beta-blockers was hypertension.
Data analysis revealed that women on beta-blockers were older
and had higher body mass index(BMI). They also had higher prevalence of chronic
comorbidities like hyperlipidemia, diabetes, hypertension, heart failure, a
history of arrhythmia and pregnancy complications like preeclampsia and eclampsia.
They also delivered about a week early than those not taking beta-blockers
(mean 37.4 weeks vs. 38.9 weeks).
In unadjusted analyses, women on beta-blockers were significantly
more likely to have a baby with congenital cardiac malformation as compared to
those not taking the drug (P < 0.001).
When after taking into account the confounders like maternal
age, BMI, and comorbidities and gestational age at delivery, there was no
longer any association between the exposure and the outcome (P = 0.32).
This suggests that the association seen in unadjusted analyses
was caused by maternal demographics and other chronic co-morbidities and not
due to beta-blockers.
“The previously reported association between beta-blocker use
and fetal cardiac anomalies in other studies may be attributed to confounding,”
Duan and colleagues concluded. “While these findings do not definitively rule
out the possibility of fetal congenital defects in association with
beta-blocker use, these results do provide reassurance regarding the use of
this class of medication for the treatment of cardiac conditions in pregnant
women.”
Access the Abstract here
Primary
source: Duan L, Ng
A, Chen W, Spencer HT, Nguyen J, Shen AY, Lee M. β-Blocker Exposure in
Pregnancy and Risk of Fetal Cardiac Anomalies. JAMA Intern Med.
2017;177(6):885-887. doi:10.1001/jamainternmed.2017.0608
