Oxymetazoline and Fetal Heart Defects
There is no established evidence that oxymetazoline causes congenital heart defects in fetuses. A controlled study specifically examining oxymetazoline's effects on fetal circulation found no significant acute changes in maternal or fetal blood flow after intranasal administration 1.
Evidence for Safety
A prospective study of 12 pregnant women in the third trimester (27-39 weeks) who received a single dose of intranasal oxymetazoline demonstrated no significant changes in fetal aortic or umbilical artery blood flow velocities, and no worrisome elevations in systolic/diastolic ratios 1.
The same study found no significant changes in maternal blood pressure or pulse rates following oxymetazoline administration, suggesting the alpha-adrenergic vasoconstrictor effects do not acutely compromise uteroplacental or fetal circulation 1.
Context on Congenital Heart Disease
Congenital heart disease affects approximately 0.9% of infants and comprises one-third of all major birth defects, but the vast majority of cardiac malformations cannot be attributed to maternal drug exposure during pregnancy 2.
The established maternal drugs with evidence for increasing congenital heart disease risk include ethanol, anticonvulsants, lithium, and exogenous female hormones—not sympathomimetic decongestants like oxymetazoline 2.
Important Caveats
The available evidence on oxymetazoline is limited to acute exposure studies in the third trimester, not first-trimester exposure during the critical period of cardiac organogenesis (which occurs before 12 weeks gestation) 3.
If a fetal cardiac defect is identified on prenatal ultrasound, the most common structural abnormalities associated with nonimmune hydrops fetalis are right heart defects, which carry a combined fetal and infant mortality of 92% 3. However, these are not linked to oxymetazoline exposure.
Fetal echocardiography between 19-22 weeks of pregnancy is recommended for all women with congenital heart disease to screen for inherited cardiac defects (risk 5% if mother affected, 2% if father affected), not for medication-related defects 3.