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Clinical Updates

Sélim Aractingi, MD, PhD

Cutaneous Physiological Signs of Pregnancy

Selim Aractingi

Thursday, October 13, 2011

As multiple signs occur in a large percentage of pregnant women, physiological changes of the skin during gestation are important to recognize and differentiate from diseases in order to reassure women and avoid unnecessary investigations (Table 1).

The three major mechanistic factors that induce the development of these changes are (i) an increase in circulating hormones secreted by the ovaries and/or placenta, including estrogens, progesterone, human placental lactogen and placental-like growth factor (PlGF), (ii) intravascular volume expansion, and (iii) compression from the enlarging uterus.

Estrogens display pleiotropic effects; they stimulate melanogenesis and keratinocyte growth, cause cutaneous vasodilatation, and may enhance angiogenesis. Progesterone acts synergistically with estrogens on melanogenesis; however, it intervenes solely to reduce collagenolytic activity. In addition, an enlargement of the pituitary gland results in increased levels of gonadotrophins, adrenocorticotrophic hormone (ACTH) and melanocytic-stimulating hormone (MSH), which all have a direct effect on the skin.

Therefore, the present article aims to give a view of how the biology - and consequently the histology and physiology - of the skin is influenced by pregnancy.

Pigmentary changes

Non-facial hyperpigmentation
- Areolae, nipples, periumbilical skin, ano-genital region, axillae, thighs
- Recent scars, naevi, freckles
- Linea nigra
- Pigmentary demarcation lines


Vascular changes

Spider telangiectasias

Palmar erythema

Venous hypertension signs
- Varicose veins and venous telangiectasias of the legs
- Hemorrhoids
- Jacquemier sign
- Chadwick sign
- Non-pitting edema
- Purpura

Vasomotor instability
- Episodic pallor, facial flushing, hot and cold sensations, dermographism, cutis marmorata.

Vascular proliferation
- Hemangiomas, glomus tumors, hemangioendotheliomas
- Hyperemia and hyperplasia of the gingival mucosa
- Oral pyogenic granulomas

Structural changes

Striae gravidarum

Molluscum fibrosum gravidarum

Adnexal changes

- Reversible hirsutism, postpartum telogen effluvium, male-pattern alopecia

- Distal onycholysis, transverse grooves, longitudinal melanonychia, subungueal hyperkeratosis

- Eccrine sweat glands: hyperhidrosis, miliara
- Apocrine sweat glands: decreased activity
- Sebaceous glands: increased activity, Montgomery's tubercles

Table 1. Physiologic changes of the skin and the mucosa during pregnancy.

Pigmentary Changes

Hyperpigmentation is the most frequent skin modification found in pregnancy,1 and it takes place, usually, during the first trimester. Its pathogenesis is considered to rely on increased serum levels of MSH, estrogens and, possibly, progesterone that stimulate melanocytic activity.2,3 Changes are more pronounced in women with a dark complexion.

Hyperpigmentation is usually localized, targeting the areolae and/or nipples, which are the most commonly affected sites (40%); it also targets the face, the periumbilical skin, the axillae, and the inner thighs. Recent scars, naevi, and freckles might also darken during gestation. The linea alba becomes hyperpigmented in approximately 75% of pregnant females.1

Melasma, chloasma, or mask of pregnancy usually begins after the third month of gestation and can affect 5% of white females devoid of sun exposure and up to 70% of those with a dark phototype. The most common presentation is centrofacial melasma developing on the forehead, the cheeks, the upper lip, and the chin. Maxillary and mandibulary patterns are less frequent. Wood's light examination helps to differentiate the epidermal (enhanced pigmentation) and dermal (unchanged pigmentation) types.

Pigmentation usually regresses postpartum; however, it might persist in some cases and/or worsen again after sun exposure. Therefore, broad-spectrum sunscreen and sun avoidance are important preventive measures during and after pregnancy.4 Additionally, its recurrence in future pregnancies or with oral contraception is common.

Vascular Changes

Spider telangiectasias - also called spider angiomas or spider nevi - develop in approximately 60% of white pregnant women; however, they are far less common in dark-skinned women.1 Typically, spider nevi appear at the end of the first trimester in the area of skin drained by the superior vena cava, namely the face, neck, arms and hands. Their number increases throughout pregnancy,1 and they often disappear within weeks after delivery; however, persistent lesions may be treated with fine-needle electrocautery, pulsed dye laser, or intense pulse light system. 

Furthermore, palmar eythema appears within the first trimester along with spider telangiectasias. Hyperthyroidism, cirrhosis, lupus, and salbutamol intake are the main differential diagnoses. Palmar erythema in pregnancy is attributed to venous capillary engorgement, and fades within one week postpartum.

Secretion of pregnancy-related hormones induces and increases the fragility of the elastic fibers in vessel walls.5,6 In addition, the enlarging uterus compresses the pelvic and abdominal vessels, thus increasing venous pressure. These, as well as prolonged standing, lead to saphenous, vulvar, and anal (hemorrhoidal) varicosities that appear in 40% of women. Varicosities usually regress postpartum. Use of elastic stockings and elevation of the legs are, therefore, recommended to prevent these phenomena. Prevention of constipation might also help to prevent their exacerbation.

Likewise, the increased hydrostatic venous pressure detailed above might also lead to fluid leakage in the extracellular milieu, which results in non-pitting edema that mainly affects the legs, but also possibly the face and the eyelids. It is more pronounced in the morning and is observed in almost half of all pregnant women during the last months of pregnancy.

However, one has to keep in mind that edema of the face and hands might be indicative of pre-eclampsia. Purpura is caused by the excessive fragility and permeability of capillaries, and is common on the legs during the second half of pregnancy; although it spontaneously regresses postpartum, it requires the elimination of other causes of purpura.

Vascular Proliferation

Superficial or subcutaneous hemangiomas, beginning on the third month of gestation, are reported in 5% of pregnant women and affect the hands and neck particularly. More rarely, glomangiomas and/or hemangioendotheliomas might develop around the eyes, the breasts, and the umbilical skin.

Hyperemia and hyperplasia of the gingival mucosa is seen in pregnant women, and develops in the third trimester of pregnancy and progressively resolves postpartum. The interdental papillae are the most affected site. Pre-existing periodontal disease, poor dental hygiene, nutritional deficiencies, and local irritative factors are co-stimulatory events. 

Similarly, pyogenic granulomas seem relatively frequent during pregnancy after the second trimester. The lesions correspond to benign hyperplasia of mucosal capillaries and fibroblasts that arises in reaction to triggers such as physical trauma or irritations. Pyogenic granulomas are painless, but they might bleed. Spontaneous regression is observed in the months after postpartum; however, their recurrence is possible in later pregnancies. Unless bleeding necessitates excision, surgery should be avoided.

Structural Changes

Striae distensae (striae gravidarum) occur in 60-90% of white women; however, they are less common in black or Asian women.1 The most significant risk factors for striae in primiparous women include young maternal age, an elevated maternal body mass index, as well as important maternal weight gain and baby weight. Additionally, women with a history of breast or thigh striae or a family history of striae gravidarum are at higher risk.7

The mechanisms of their appearance remain poorly known, but rely on physical trauma such as stretching of the skin and hormonal mediation through steroids, estrogens and relaxin, which leads to a reduction in the elastic fiber network.8

Furthermore, preventive measures have no proven beneficial effect. Treatment of recent purplish striae with a pulsed dye laser or 0.1% tretinoin cream might partially improve their appearance; however, it should, of course, be given only after delivery.9

Molluscum fibrosum gravidarum corresponds to the skin tags, or acrochordons, that grow during pregnancy, which appear as small cutaneous pedonculated, lightly pigmented polyps located on the skin folds. 

Adnexal Changes

The hair cycle changes during pregnancy, which results in less anagen hair follicles entering the telogen phase and leads to the thickening and brightening of hairs. In addition to the thickening of scalp hair, body hair follicles increase in size and number, especially on the face, but less often on the arms, legs, and back. This kind of hirsutism is reversible within 6 months postpartum.

Postpartum, scalp hair enters a prolonged telogen phase, causing increased shedding (telogen effluvium), which might begin 4-12 weeks after delivery and last 3-4 months. After this period, hair grows again within 6-15 months. An evaluation of the possibility of an iron deficiency should be made.

Acne will not be discussed in detail here; however, it is a well known phenomenon that acne can develop de novo or worsen during pregnancy. The difficulty lies in choosing an allowed treatment because most of them are forbidden during pregnancy.

In approximately half of pregnant women, the sebaceous glands on the areolae enlarge and appear as multiple elevated brown papules called Montgomery's glands or tubercles. They are visible from the sixth week of gestation, representing an early sign of pregnancy. Regression is classical after delivery.

In conclusion, this short review summarizes the diversity of the interactions between pregnancy and a vast and complex organ such as the skin - there is nearly a target receptor for any of the pregnancy hormones on one or more cutaneous cell types. Therefore, pregnancy can induce a wide range of changes, ranging from pronounced physiological changes to more significant disorders. Clinicians need to understand the molecular basis of these changes and be able to interact with obstetricians in order to provide the best treatment for pregnant women.


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