The skin and pregnancy: Physiological changes and dermatoses
The hormonal and physical milieu of pregnancy precipitates many cutaneous skin changes, among them pigmentation and vascularity. All are considered normal during pregnancy and yet evoke significant patient anxiety. Specific puerperal skin conditions represent dermatoses of pregnancy and have variable physical presentations. Here we review both common skin changes and dermatoses of pregnancy.
Physiological skin changes
Case One: A 23-year-old G1 at 27+3 weeks’ gestation with an uncomplicated pregnancy presents for her routine prenatal care appointment complaining of abdominal striae and a darkening linea.
Generalized and localized hyperpigmentation occurs in 90% of pregnant women and is more pronounced in darkly pigmented skin.1 The pigmentary response—which is regarded as endocrine in origin—presents in already pigmented areas such as the linea alba, axilla, navel, vulva, and face2 (Figures 1 and 2).
In some patients, increased facial pigmentation involves the cheeks, forehead, and bridge of the nose, presenting a characteristic picture that has been called the “mask of pregnancy” or chloasma or melasma gravidarum. Chloasma occurs in 3 patterns: centrofacial, malar, and mandibular.3 After delivery, the pigmented areas gradually fade. However, chloasma is persistent in approximately 30% of patients and can be induced by estrogen-containing oral contraceptives (OCs). Chloasma also tends to recur with subsequent pregnancies and appears earlier in gestations with subsequent pregnancies. Patients who suffer from chloasma must be counseled regarding recurrence in the setting of OCs and should be advised to use sunscreen because sun exposure increases hyperpigmentation. Chloasma is more prevalent in patients with Fitzpatrick skin types IV-VI (moderate-brown Mediterranean skin tone to black skin tone). If medication is desired, hydroxyquinone cream can be used in pregnancy.
Striae gravidarum (Stretch marks)
Striae gravidarum or stretch marks of pregnancy occur in most pregnancies during the second or third trimester and have a familial and racial predisposition.4 Fifty percent to 80% of pregnant women experience at least a few striae and they are severe in about 10% of cases, especially in teenagers (Figure 3). Risk factors for more severe striae include maternal family history, young maternal age, non-white race, higher baseline and delivery body mass index (BMI), and increased abdominal and hip girth.5 No evidence exists for the efficacy of anecdotal treatments, but elective laser cosmetic surgery is an option post-partum. Data in the literature are conflicting regarding the effects of tretinoin cream on the appearance of striae, but use of a topical retinoid during pregnancy is contraindicated.6,7