Which sunscreen is suitable for a pregnant woman?

During pregnancy, significant hormonal fluctuations occur. Among these, there is a marked increase in the levels of oestrogen and progesterone, which are steroidal hormones. These hormones stimulate the process of melanogenesis, that is, the synthesis of melanin, the pigment responsible for skin colouration. Therefore, when exposed without sun protection, pregnant women are more prone to hyperpigmentation, resulting in the appearance of the "pregnancy mask". These brown spots typically appear from the fourth month of pregnancy and predominantly affect individuals with darker skin, from phototypes III to VI in the FITZPATRICK classification. Indeed, darker skin contains more melanin than lighter skin, and specifically more eumelanin, a darker form, which provides better protection against UV rays.

Furthermore, it is not uncommon for some pregnant women to experience tightness and feelings of dryness on their skin, due to the hormonal and structural changes their bodies undergo during pregnancy. As a result of weight gain, the cells of the stratum corneum are stretched and their barrier function is weakened. Ceramides, which play a role in intercellular junctions, then allow more water to escape, increasing the risk of skin dehydration. This can be exacerbated by exposure to the sun, whose UV rays are drying to the skin as they weaken the hydrolipidic film present on its surface.

Finally, the blood circulation intensifies in a woman's body from the fourth week of pregnancy, a period corresponding to the beginning of blood exchanges between the mother and the embryo. This then causes an increase in body temperature. This increase is heightened when exposed to the sun, where the solar UV rays heat the epidermis and have a vasodilatory action.

It is crucial toapply a broad-spectrum sunscreen daily to exposed areas during pregnancy, regardless of one's skin type. For optimal protection and a minimal risk of developing "melasma", it is recommended to choose a sunscreen with an SPF of 50 or higher. The SPF is calculated based on the protection the product provides against UVB rays. For the product to also protect against UVA rays, the term "broad-spectrum protection" must be indicated. As a reminder, an SPF 30 product allows approximately 3% (≈ 1/30th) of UVB rays to penetrate, while an SPF 50 product only allows 2% (= 1/50th) to get through. The difference may seem minimal, but it is actually significant.

At Typology, we offer a complete range of sun care products (SPF 30 and SPF 50), suitable for pregnant women, providing protection and hydration to the skin, thanks to their richness in aloe vera (INCI: Aloe Barbadensis Leaf Juice Powder), in hyaluronic acid (INCI: Hydrolyzed Hyaluronic Acid) and in karanja oil (INCI: Pongamia Glabra Seed Oil) for facial sun creams. These treatments are hypoallergenic and do not contain any allergenic ingredients.

Sunscreen filters are fundamental to the operation of sun creams. Incorporated into a sun cream, they protect the skin from UVA and UVB rays. There are two types of sunscreen filters : organic filters and mineral filters. The organic filters often get a bad press, as some are suspected to be endocrine disruptors. This is particularly the case for octocrylene, octinoxate and oxybenzone. Some preservatives such as BHT are also criticised.

Regarding oxybenzone, studies in vitro and theoretical data suggest that it could cause a congenital malformation (Hirschsprung's disease) or lead to uterine enlargement, but this has not been proven in vivo. This molecule has also been found in breast milk, although this has not been shown to have negative effects on babies. However, as a precaution, it is better to avoid sun creams that contain it.

The same applies to BHT, a study on mice has shown that it causes decidualisation of the endometrium at the beginning of pregnancy, meaning it disrupts the process by which endometrial cells undergo changes to accommodate the embryo. This increases the risk of miscarriage.

This is why it is generally recommended for pregnant women to opt for mineral filter sun creams. In terms of effectiveness, both types of sun filters are equivalent. However, it's worth noting that it's not necessary to avoid all sun creams containing organic filters during pregnancy. Indeed, not all are suspected to be endocrine disruptors and most are risk-free.

To protect your skin during pregnancy, opting for sun creams formulated for children may seem like a viable option at first glance. This type of care is often considered gentler and suitable for sensitive skin. In reality, the "for children" labels are not monitored for sun creams and some contain allergenic ingredients or are not suitable for sensitive skin. It is therefore better to pay attention to the INCI list, which details which molecules can be found in the product. We also recommend being cautious if you choose a sun protection in spray form. When spraying on the face, it is important to not inhale or ingest any product.

Important : Although the application of sunscreen provides the skin with protection against UV rays, it is preferable to limit exposure time, especially between 12pm and 4pm. Indeed, it is during this period of the day that the rays are most intense. Furthermore, it is recommended to favour covering clothing and to wear a hat and sunglasses.

• TYLER K. H. Physiological skin changes during pregnancy. Journal of Clinical Gynecology and Obstetrics (2015).

• CAMELI N. & al. Melasma: How hormones can modulate skin pigmentation. Journal of Cosmetic Dermatology (2019).

• DOWNS C. & al. Can oxybenzone cause Hirschsprung's disease? Reproductive Toxicology (2019).

• SIRITHANABADEEKUL P. & al. Ultraviolet filters in sunscreen products labeled for use in children and for sensitive skin. Pediatric Dermatology (2020).

• HE J. Exposure to butylated hydroxytoluene compromises endometrial decidualization during early pregnancy. Environmental Science and Pollution Research International (2021).