How to combat hyperpigmentation during pregnancy?

The pigment responsible for skin pigmentation is melanin. Produced by melanocytes and transferred to the surface of the epidermis, it provides a certain level of protection to the skin against the sun and gives it its natural colour. However, during pregnancy, the body undergoes several hormonal variations, including an increase in the production of oestrogen and progesterone.

According to several studies, these steroidal hormones are capable of stimulating the expression of type I melanocortin receptors (MCIR), playing a role in the melanin synthesis pathway. This overproduction of pigments is the cause of the appearance of brown spots on the face or body of pregnant women, also referred to as "pregnancy mask".

It is also worth noting that hyperpigmentation predominantly affects individuals with darker skin, specifically those within phototypes III to VI in the FITZPATRICK classification. Indeed, darker skin contains more melanin than lighter skin, and more specifically eumelanin, a darker form, which provides better protection against UV rays.

Once established, it should be noted that hyperpigmentation spots take quite a long time to fade naturally. They generally take a year to diminish and, in some cases, are permanent. Thus, the prevention remains the best option. For this, apply a broad-spectrum sunscreen daily to combat the effects of UVA and UVB rays, and limit the appearance of new pigmentation spots.

There are, however, certain actions that can help to diminish the appearance of pigmentation spots. Indeed, there are treatments specifically designed for this purpose. It is even recommended to use them before the spots appear, as a preventative measure. They are often rich in depigmenting agents, such as kojic acid or tranexamic acid and exfoliants, such as glycolic acid, lactic acid or gluconolactone.

In terms of their mode of action, depigmenting ingredients work by inhibiting tyrosinase, the enzyme that allows the conversion of tyrosine into melanin. This effectively blocks its production and reduces hyperpigmentation. Other active ingredients are capable of preventing the transfer of melanin from melanocytes to keratinocytes.

Exfoliating ingredients, on the other hand, are capable of targeting the corneocytes of the stratum corneum and trigger their degradation, which induces skin peeling. By breaking the bonds between dead cells, it allows for a smoother and more radiant complexion. Indeed, this gradually eliminates the pigmented cells located on the surface of the epidermis. In addition to depigmenting creams, it is beneficial to perform one to two exfoliations per week. These promote cellular renewal and the surfacing of less pigmented cells on the epidermis.

A recommendation?

At Typology, we have developed a serum suitable for pregnant women and capable of diminishing hyperpigmentation marks. Enriched with 5% tranexamic acid, it targets hyperpigmentation at its source by limiting the synthesis of melanin and blocking the interaction between skin cells and melanocytes. This serum also contains tetrapeptides, which further inhibit certain reactions in the melanogenesis process, thereby reducing pigmentation spots. Moreover, these active ingredients possess a strong antioxidant power that ensures the skin's protection against free radicals and revives its natural glow.

Thehydroquinone is a molecule frequently used in depigmenting creams, due to its effectiveness in inhibiting tyrosinase and reducing hyperpigmentation. Studies have also highlighted hydroquinone's ability to decrease the number of melanocytes in the epidermis.

However, it should be noted that the use of hydroquinone has been banned in cosmetic products in Europe since 2000. This substance is considered a drug and is therefore regulated by the National Agency for the Safety of Medicines and Health Products (ANSM).

Its use is, however, strongly discouraged for pregnant women. Indeed, the Food and Drug Administration (FDA), the US equivalent of the ANSM, has classified hydroquinone as a category C substance during pregnancy. This means that reproductive studies conducted on animals have shown undesirable side effects on the foetus, but there is a lack of controlled studies in the human population.

It appears that once in the epidermis, hydroquinone is capable of being absorbed by the blood vessels and subsequently found in the bloodstream. As previously stated, there are not enough scientific studies to assert that hydroquinone can then be transmitted to the baby during pregnancy, but its molecular weight is theoretically low enough for it to cross the placental barrier.

• MIOT H. & al. Melasma: a clinical and epidemiological review. Anais Brasileiros de Dermatologia (2014).

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

• EMER J. & al. Melasma and Post Inflammatory Hyperpigmentation: Management Update and Expert Opinion. Skin therapy letter (2016).