Once you find out you're pregnant, even the serum you use every night starts to look suspicious. Some of what you put on your skin can be absorbed into the body, so the answer comes from medical literature rather than cosmetics rules. This guide sticks to what the American College of Obstetricians and Gynecologists (ACOG), the U.S. Food and Drug Administration (FDA) and peer-reviewed studies agree on. Hydroquinone is a separate case because Korea keeps it out of cosmetics altogether.
One thing to know up front. Most of the ingredients here are not on the list because they were proven to harm people. The advice rests on animal studies, observational research and theoretical risk, and pregnancy data is thin, so the standard move is to hold off on the precautionary principle. The ingredients with a confirmed link to birth defects, such as isotretinoin, are oral medicines and not cosmetics.
The 6 ingredients to avoid
1. Retinoids
Oral isotretinoin, the acne pill, is well known for causing birth defects. Topical retinoids belong to the same family. They absorb in small amounts, but the standard advice is still to save them for after delivery.
How it appears on labels: Retinol, Retinyl Palmitate, Retinyl Acetate, Retinaldehyde, Tretinoin, Adapalene, Tazarotene, Isotretinoin
The birth defects linked to vitamin A come from high-dose oral vitamin A and oral retinoid drugs. Topical products absorb at low rates and have not been shown to cause harm. ACOG still advises skipping them during pregnancy. A 2022 dermatology review in the Journal of the Korean Medical Association lands in the same place: no evidence of more birth defects, but wait until after delivery as a precaution.
A 2026 Nordic study in the British Journal of Dermatology paints the same picture. It looked at about 3.87 million babies across four countries. Among those whose mothers used a prescription topical retinoid in the first trimester, 3.3% had a major birth defect, against 3.0% in unexposed babies. The researchers did not see a higher risk. They still wrote that people who are pregnant or planning to be should avoid topical retinoids because the data has limits. So if you used one before you knew, this is reassuring. Once you know, the advice is to pause.
2. High-strength salicylic acid
Low strengths like a wash-off cleanser are generally considered fine. What to watch is peel-level strength, or use over a wide area for a long stretch.
Salicylic acid is a salicylate, the same family as aspirin. Large amounts reaching the whole body have been linked to fetal complications. That is why topical products at 2% or below are generally treated as safe, while high-strength chemical peels and long-term use are best skipped. The American Academy of Dermatology (AAD) also says topical salicylic acid is generally considered safe when used for a limited time.
Korean cosmetics rarely get near that line anyway. Wash-off cleansing products can contain up to 2% and acne-care functional products up to 0.5%. If strength is the worry, the place to look is a clinic peel rather than your cosmetics shelf.
3. Hydroquinone
Hydroquinone is a topical brightening agent with high skin absorption, around 35 to 45%. Pregnancy safety data is lacking too, so the standard advice is to stop using it.
In Korea hydroquinone is a prohibited cosmetic ingredient under the MFDS Regulation on Cosmetic Safety Standards and is used only as a prescription medicine. You won't find it on Korean cosmetic labels. Products bought from overseas can still contain it, so those are the ones to check.
4. Formaldehyde-releasing preservatives
These preservatives slowly release formaldehyde as they break down. The International Agency for Research on Cancer (IARC) classes formaldehyde as a Group 1 carcinogen, so keeping exposure low in pregnancy is advised.
How they appear on labels: DMDM Hydantoin, Quaternium-15, Imidazolidinyl Urea, Diazolidinyl Urea, Bronopol (2-Bromo-2-Nitropropane-1,3-Diol)
In Korea an MFDS notice bans formaldehyde itself from cosmetics, and the preservatives above have set limits. The bigger exposure is known to come from breathing it in during hair-straightening treatments rather than from skincare. Still, there's no reason to reach for these products during pregnancy when plenty of others exist.
5. Chemical UV filters (oxybenzone and similar)
Oxybenzone (BP-3) is an ingredient the FDA and EU have flagged over concerns that it may affect the endocrine system. Some studies have found it in maternal blood, breast milk and the placenta. That is why a switch to mineral sunscreen is the usual advice.
Recommended to avoid: Oxybenzone (Benzophenone-3), Octinoxate (Ethylhexyl Methoxycinnamate), Homosalate
What to use instead: Zinc Oxide and Titanium Dioxide. They stay on the surface of the skin, so very little is absorbed.
In its 2021 sunscreen review the FDA found enough safety data for both mineral filters. For oxybenzone and octinoxate it asked for more data before making a call. That is a decision on hold, not a finding of harm. Either way, wearing sunscreen matters far more than skipping it, so switch to a mineral formula instead of going without.
If you shop Korean sunscreens, octinoxate is the one to look for first. Across the 2,426 ingredient lists in the Beauty Dupe database (October 2026), not a single product contained oxybenzone, while octinoxate showed up in 68. Korean labels list them as Benzophenone-3 and Ethylhexyl Methoxycinnamate.
6. Phthalates and certain fragrances
Some phthalates such as DEHP and DBP are classed as endocrine disruptors. The catch is that they can hide inside the blend labeled simply as Fragrance or Parfum.
Korea requires the fragrance allergens listed by the MFDS to be named once they pass a set concentration. Everything else can sit under the single word "Fragrance," so the label alone won't tell you what is inside. During pregnancy the simplest route is a fragrance-free product. Essential oils such as clary sage and rosemary are often flagged for early pregnancy, though the evidence behind that advice is thin.
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Retinoids that never say "retinol"
Korean ingredient lists are written in Korean, so memorizing the English names above only gets you so far. ACOG notes that retinoids turn up in over-the-counter products as well as prescriptions, and it tells readers to check labels carefully.
Of the 2,426 ingredient lists in the Beauty Dupe database (October 2026), 121 products contained at least one retinoid. In 34 of them the word "retinol" never appears. Searching a label for "retinol" alone would miss more than one in four.
| Name on the label | Products in the Beauty Dupe database |
|---|---|
| Retinol | 87 |
| Hydroxypinacolone Retinoate | 32 |
| Retinal | 22 |
| Retinyl Palmitate | 15 |
| Retinyl Acetate | 2 |
| Retinyl Propionate | 1 |
Hydroxypinacolone Retinoate is the easiest one to miss because the retinoid part sits in the middle of a long name. Retinal is the other trap. On Korean labels it is usually spelled 레틴알 (20 of the 22 products), which doesn't look like retinol at a glance. Both are retinoids, so the advice is the same. Tretinoin and adapalene are prescription acne medicines, and if you use either one it's worth telling your OB-GYN at your first visit.
