Impact of pregnancy on the skin

More than 90% of all pregnant women experience a range of pregnancy-related changes:

• hormonal,
• immunological,
• metabolic and vascular,

which can lead to significant skin modifications, whose occurrence may greatly impact their quality of life.¹

Some of these modifications are physiological and due to hormonal changes, but the course of pre-existing skin conditions may also be impacted, either improving or worsening. There is also a heterogeneous group of specific conditions, known as dermatoses of pregnancy, that only appear during pregnancy or the post-partum period.¹

A more detailed overview

Immunological changes during pregnancy¹

The mother’s immune response is considerably diminished during pregnancy, to avoid rejection of the foetus.
The gestational cytokine profile reflects immune tolerance, marked by increased Th2 (IL-4, IL-5, IL-10, IL-13) expression. In contrast, the post-partum period is characterised by elevated Th1 (IL-2, TNF-a, IFN-c) levels.

Hormonal changes contribute to this unique cytokine profile in the following ways:

• Estradiol inhibits IL-2 production.
• Progesterone stimulates IL-4, IL-5 and IL-10 production. It also inhibits TNF-a secretion. Glucocorticoid levels rise, inhibiting the production of IL-1, IL-2, TNF-a and IFN-c, and stimulating the synthesis of IL-10, IL-4 and IL-13.

Pigmentary disorders, the condition most commonly experienced¹

These disorders generally begin to appear during the 1^st trimester of pregnancy.²

The prevention of pigmentary disorders involves:

• Avoiding sun exposure
• Using high-factor UVA/UVB-blocking sunscreens (SPF 50 or higher).³

Stretch marks, a genuine aesthetic concern

Between 50%-90% of women develop stretch marks during the 6th and 7th months of pregnancy, mostly on the abdomen, thighs, hips and breasts, where most stretching occurs.^1,2,4-7

When they first appear, they are either red or purple, and sometimes oedematous, slowly fading in colour but never disappearing.^5,6,8

In the most severe cases, they cause itching and discomfort and may disturb sleep, thus negatively affecting quality of life.^5-7

Stretch marks are the result of weakened elastin and collagen fibres, and their unsightliness is often a cause of distress for women. Their development may have a genetic component since they are rare among certain ethnic groups.²

These marks seem to be an effect of damage to fibroblasts, inhibition of the synthesis of macromolecules, and lower levels of mRNA coding for collagens I and III and fibronectins.

They are apparently the consequence of the degeneration of collagen and the microfibril structures of elastic fibres, especially fibrillin.^4,8

Since emollients moisturise the skin and increase its elasticity, they may be used to prevent stretch marks. To date, no treatment has been proven effective as a cure for stretch marks.^5,7,8

Pruritus, not to be overlooked

Further information

Dermatoses of pregnancy

Polymorphic eruption of pregnancy is among the most common (0.6%). It occurs at the end of pregnancy^{.9 ,10}
It begins on the abdomen, lasts 6 weeks on average, and spontaneously clears up a few days after childbirth.¹⁰ This benign inflammatory disorder takes the form of urticarial papules that may converge into plaques.
In 40%-70% of all cases, blisters may be seen covering stretch marks.
The proposed physiopathological hypothesis is that the stretching of abdominal skin damages underlying conjunctive tissue, thus triggering an inflammatory reaction.¹¹

Intrahepatic cholestasis of pregnancy is more frequently observed in Scandinavia and in the Amerindian populations of Chile and Bolivia.
It is also more common among older women, after multiple pregnancies, when there is a history of cholestasis during oral contraceptive use, and in the winter.^9,10
This condition begins during the 2nd or 3rd trimester of pregnancy, with intense pruritus affecting the palms and soles—in the absence of pre-existing skin lesions—before spreading. Itching is more severe during the night and may disturb sleep.⁹
Intrahepatic cholestasis of pregnancy is the result of the intrahepatic obstruction of bile flow, in the absence of hepatitis.¹¹

Pemphigoid gestationis is an autoimmune disease that develops during the 2nd trimester and is characterised by pruritic urticarial papules, plaques and blisters in the umbilical region.
It disappears a few weeks or months after childbirth.¹¹

Atopic eruption of pregnancy: Lesions develop during the 1st or 2nd trimester, on the face, neck, chest and in skin folds.^9,11
In most cases (80%), subjects have never before presented symptoms of atopy, or have undergone a very long period of remission following a previous episode of atopy.⁹

Other notable modifications of the skin and skin appendages

• Slight to moderate hirsutism as well as hypertrichosis, most often disappearing after childbirth and due to estrogenic and androgenic stimulation during the 2^nd half of pregnancy.¹
• Nails commonly become brittle.¹
• Spider veins (i.e. nevi or telangiectasia) are believed to be present in nearly half of all pregnant women.²
• Palmar erythema is believed to affect two-thirds of Caucasian women and one-third of black women.¹
• Approximately 5% of pregnant women exhibit capillary haemangioma, usually on the head and neck.¹
• Gingival neoplasms of pregnancy (granuloma gravidarum) arise at the gingival papillae and usually clear up spontaneously after childbirth.¹