Polyhydroxy Acids (PHAs) are chemical exfoliants commonly found in skincare products, often marketed as a gentler alternative to other exfoliating acids. During pregnancy, many individuals adjust their routines due to concerns about topical ingredients and their potential effects on a developing fetus. The primary worry centers on whether active components can be absorbed through the skin and enter the maternal bloodstream. Understanding the unique structure of PHAs is key to determining their safety profile.
Understanding PHAs and Their Mechanism
PHAs, which include Gluconolactone and Lactobionic Acid, function similarly to Alpha Hydroxy Acids (AHAs) by promoting the shedding of dead skin cells. They are considered a second-generation of AHAs, offering moisturizing and antioxidant benefits in addition to exfoliation. The fundamental difference is their significantly larger molecular structure.
This increased size prevents the acid from penetrating deeply into the skin’s layers, meaning the exfoliation remains superficial and occurs mostly on the surface. This gentle action results in less potential for irritation compared to smaller-molecule acids like Glycolic Acid. Because PHAs work primarily at the skin’s surface, they provide a smoother texture and brighter appearance without compromising the skin barrier function.
Systemic Absorption and Pregnancy Risk
The safety of any topical ingredient during pregnancy depends largely on the amount absorbed through the skin and subsequently entering the systemic circulation—a process known as systemic absorption. Since PHAs have a large molecular weight, their penetration into the deeper layers of the epidermis and dermis is significantly limited. This restricted penetration means the amount of PHA that could potentially be absorbed into the bloodstream is considered negligible by dermatologists. This characteristic is the main reason why PHAs are widely regarded as a low-risk option during pregnancy.
This contrasts with ingredients where systemic absorption is a known concern, such as prescription-strength topical Retinoids (Vitamin A derivatives). Oral Retinoids are classified as a Class X drug and are strictly prohibited, and topical versions are generally avoided due to potential systemic effects.
Another common exfoliant, Salicylic Acid (a Beta Hydroxy Acid or BHA), is sometimes advised to be used sparingly. Higher concentrations or application over a large body surface area carry a theoretical risk of systemic absorption, leading to caution among healthcare providers. PHAs bypass this concern because their physical size inherently limits their absorption, providing a safer alternative for chemical exfoliation.
How to Incorporate PHAs Safely
For individuals who wish to incorporate PHAs into their pregnancy skincare routine, a measured and cautious approach is recommended. Before applying any new active product, a patch test is recommended by applying a small amount to an inconspicuous area, like behind the ear or on the inner arm, to check for a reaction. Start with a product that has a lower concentration and use it only a few times per week to allow the skin to adjust.
If the skin tolerates the PHA well, the frequency of use can be gradually increased. It is recommended to consult a healthcare provider or board-certified dermatologist before introducing any new active ingredients during pregnancy.
For those who prefer to avoid all active exfoliating acids entirely, alternatives like Azelaic Acid are frequently recommended by dermatologists for managing pregnancy-related skin concerns, such as acne and hyperpigmentation. Azelaic Acid is classified as a Category B drug by the FDA, indicating it is largely considered safe for use during pregnancy.