Safety of Zinc Oxide 8.5% and Benzalkonium Chloride 0.1% Ointment During Pregnancy
This ointment formulation appears safe for topical use during pregnancy, as zinc oxide is well-established as safe and the benzalkonium chloride concentration (0.1%) falls within accepted safety limits for topical antimicrobial use.
Evidence Supporting Safety
Zinc Oxide Component (8.5%)
Zinc oxide is recommended for use during pregnancy across multiple dermatologic conditions, with the American Academy of Dermatology supporting its application as a protective barrier agent 1
The Journal of the American Academy of Dermatology specifically recommends zinc pyrithione (a zinc compound) for pregnant patients with hidradenitis suppurativa, noting it is "unlikely to be associated with increased risks in pregnancy based on its mechanism of action" 2
Oral zinc supplementation receives a strong recommendation with moderate quality evidence for safety in pregnancy, indicating the systemic absorption from topical zinc oxide poses minimal concern 2
Zinc oxide functions as a protective barrier on skin, with immune-modulating properties that are beneficial rather than harmful 3
Benzalkonium Chloride Component (0.1%)
The concentration of 0.1% BAC in this formulation matches the maximum concentration deemed safe by the American College of Toxicology for antimicrobial use 4
This exact concentration (0.1%) is found in DermolÒ cream, which is listed as an acceptable emollient option in dermatologic guidelines for general use 2
While BAC can exert toxic effects at higher concentrations or with systemic exposure, topical application at 0.1% in an ointment base results in minimal systemic absorption 5, 4
The Journal of the American Academy of Dermatology recommends chlorhexidine and bleach baths as antiseptic washes during pregnancy, suggesting topical antiseptics are generally acceptable when benefits outweigh theoretical risks 2
Mechanism of Safety
Zinc oxide remains primarily on the skin surface as a physical barrier rather than being absorbed systemically, which is why it's recommended for sun protection and skin protection during pregnancy 6
The ointment vehicle (oil-based) further limits systemic absorption of both active ingredients 7
Neither ingredient crosses the placenta in clinically significant amounts when used topically at these concentrations 1, 4
Clinical Application Guidelines
Apply to affected areas as needed, typically 2-3 times daily after gentle cleansing 3
Use on intact or mildly inflamed skin; avoid application to large open wounds or extensively denuded areas to minimize any theoretical systemic absorption 3
For diaper dermatitis, perineal irritation, or minor skin inflammation during pregnancy, this formulation provides both barrier protection (zinc oxide) and antimicrobial activity (BAC) 7, 8
Continue regular emollient use between applications to maintain skin barrier function 1
Important Caveats
Avoid prolonged continuous use over large body surface areas (>20% BSA) as a precautionary measure, though no specific toxicity data suggests harm 2
If signs of contact dermatitis develop (increased redness, itching, or irritation), discontinue use and consider zinc oxide alone without the BAC component 2
The antimicrobial benefit of BAC may be reduced in the presence of high salt concentrations or certain other ingredients, but this doesn't affect safety 7
While BAC at 0.1% has been used safely in intranasal products for extended periods, topical dermal use poses even less risk due to the skin's barrier function 4
Comparison to Pregnancy-Rated Alternatives
This formulation is safer than many pregnancy category C topical agents like topical dapsone, tacrolimus, or pimecrolimus that are sometimes used for inflammatory skin conditions 2
It avoids the concerns associated with topical retinoids (teratogenic), salicylic acid in large amounts (systemic absorption risk), or potent corticosteroids (potential fetal effects with prolonged use) 2
The combination provides antimicrobial coverage similar to topical clindamycin (pregnancy category B) but without antibiotic resistance concerns 2