The main sunscreen ingredient to avoid during pregnancy is oxybenzone, a chemical UV filter found in roughly 70% of sunscreen products. It’s a recognized endocrine disruptor that crosses both the skin barrier and the placenta, reaching the fetus at levels high enough to potentially interfere with embryonic development. Beyond oxybenzone, a few other ingredients deserve caution. The good news: mineral sunscreens based on zinc oxide or titanium dioxide offer strong protection without the same concerns.
Why Oxybenzone Is the Biggest Concern
Oxybenzone is the most studied chemical sunscreen ingredient in pregnancy, and the findings are not reassuring. It’s a small molecule that absorbs through the skin easily, and studies have detected it in the urine, blood, and umbilical cord blood of pregnant women. The European Commission estimates that about 3.7% of the oxybenzone applied to skin gets absorbed into the bloodstream, with some estimates ranging as high as 13.7% depending on the formulation. For a typical daily application, that could mean anywhere from 3.5 to 480 milligrams entering a woman’s body in a single day.
Once in the bloodstream, oxybenzone crosses the placenta and reaches the fetus. Research published in peer-reviewed journals has linked medium to high urinary levels of oxybenzone in pregnant women to an increased risk of Hirschsprung’s disease in newborns, a condition where nerve cells fail to develop properly in part of the intestine. Lab testing on human cell lines confirmed that even low concentrations of oxybenzone can disrupt the migration of neural crest cells, which are critical during early embryonic development. Oxybenzone also acts as an endocrine disruptor, meaning it can mimic or interfere with hormones at a stage when hormonal signaling guides fetal growth.
Other Chemical Filters Worth Avoiding
Oxybenzone gets the most attention, but it isn’t the only chemical UV filter that enters the bloodstream. Octinoxate (also listed as octyl methoxycinnamate) is another common chemical filter that absorbs through the skin. While the pregnancy-specific data on octinoxate is thinner than for oxybenzone, it has shown hormonal activity in animal studies, and many dermatologists recommend pregnant women steer clear of it as a precaution.
Homosalate, avobenzone, and octocrylene are additional chemical filters that the FDA has flagged for further safety testing because they exceed the threshold of toxicological concern when absorbed. None of these have the same volume of pregnancy-specific research as oxybenzone, but given that safer alternatives exist, many experts suggest avoiding the entire category of chemical absorbers during pregnancy.
Skip Sunscreens With Retinyl Palmitate
Some sunscreens, particularly those marketed as “anti-aging” or combined with skincare benefits, contain retinyl palmitate, a form of vitamin A. Retinoids are well established as a concern in pregnancy. While topical absorption is low, there are published case reports of birth defects consistent with retinoid embryopathy associated with topical tretinoin use. The consensus from dermatology and obstetric guidelines is straightforward: women should not use topical retinoids during pregnancy, and that includes sunscreens that sneak them in as an added ingredient. Check the label for retinyl palmitate, retinol, or any ingredient with “retin” in the name.
What Makes Mineral Sunscreen Safer
Mineral sunscreens use zinc oxide or titanium dioxide as their active ingredients. Instead of absorbing into your skin and filtering UV rays chemically, these minerals sit on top of the skin and physically block the rays from reaching it. Because they aren’t absorbed through the skin, they don’t enter the bloodstream and don’t reach the fetus. This is why organizations like MotherToBaby, a leading resource on exposures during pregnancy, specifically recommend mineral sunscreens as a preferred option.
Between the two minerals, zinc oxide offers broader protection. Both block UVB rays (the kind that cause sunburn), but zinc oxide is more effective at blocking UVA rays, which penetrate deeper into the skin and drive premature aging and pigmentation changes. For pregnancy, when hormonal shifts already make your skin more prone to dark patches, that broader UVA coverage matters.
The Nanoparticle Question
Many modern mineral sunscreens use nanoparticle-sized zinc oxide or titanium dioxide to reduce the white cast that older formulations left on the skin. This raises a reasonable question: can those tiny particles get absorbed?
Research from Rutgers University found that inhaled titanium dioxide nanoparticles can cross the placental barrier in rats, reaching fetal tissues. The placenta did not filter them out. However, this involved inhalation, not skin application. When applied as a lotion or cream, mineral sunscreen particles sit on the skin’s surface and don’t penetrate into the bloodstream, even in nanoparticle form. The key distinction is the route of exposure: rubbed on the skin, they stay put; inhaled as an aerosol, they can travel through the lungs and into the blood.
This is why spray sunscreens, even mineral ones, deserve caution during pregnancy. If you use a zinc oxide or titanium dioxide product, choose a lotion, cream, or stick rather than a spray to avoid inhaling the particles.
Why Sunscreen Still Matters During Pregnancy
Avoiding certain ingredients doesn’t mean skipping sunscreen altogether. Pregnancy hormones make your skin significantly more vulnerable to UV-triggered pigmentation changes, commonly called melasma or “the mask of pregnancy.” Sun exposure is the primary driver, and the hormonal changes of pregnancy make it worse. One study found that using a broad-spectrum physical sunscreen starting in the first trimester reduced the incidence of melasma by more than 90%.
Melasma can take months or years to fade after delivery, and in some cases it becomes permanent. Using a mineral sunscreen with a high SPF from early pregnancy is the single most effective preventive measure, since the genetic and hormonal factors behind melasma aren’t something you can control.
How to Choose the Right Product
When shopping for sunscreen during pregnancy, flip the bottle and check the active ingredients. Here’s what to look for and what to avoid:
- Use: Zinc oxide, titanium dioxide, or both. These are the only two active ingredients in mineral sunscreens.
- Avoid: Oxybenzone, octinoxate, homosalate, octocrylene, avobenzone. These are chemical UV filters that absorb into the bloodstream.
- Avoid: Retinyl palmitate or any retinoid listed among inactive ingredients.
- Choose: Lotion, cream, or stick formulations over sprays to prevent inhaling mineral particles.
- Choose: Broad-spectrum coverage (blocks both UVA and UVB) with SPF 30 or higher.
Tinted mineral sunscreens offer an added benefit: the iron oxides used for tinting also block visible light, which contributes to melasma. If you’re prone to dark spots or have noticed pigmentation changes, a tinted formula provides an extra layer of protection that untinted sunscreens don’t.
Labels like “reef-safe” or “clean” aren’t regulated terms and don’t guarantee a product is free of chemical filters. Always verify by reading the active ingredients list rather than relying on marketing claims on the front of the bottle.