Pregnancy And Cutaneous Changes

HORMONAL CHANGES IN PREGNANCY

Pregnancy is a time of significant and complex physiologic changes. Some of these changes are due to the de novo production of a variety of protein and steroid hormones by the fetoplacental unit as well as to the increased activity of the maternal pituitary, thyroid, and adrenal glands. The currently recognized hormones produced by the placenta include the protein hormones human chorionic gonadotropin (HCG), human placental lactogen (HPL) or human somatomammotropin, human chorionic thyrotropin, and human chorionic corticotropin, as well as the steroid hormones progesterone and estrogen. A description of the chemistry, function, and metabolism of these hormones is beyond the scope of this chapter, but it should be kept in mind that the production and the serum levels of these hormones are dynamic. For instance, HCG levels peak between the tenth and twelfth weeks of gestation, although they remain elevated throughout pregnancy. The levels of progesterone and estrogen rise throughout the first and second trimesters of pregnancy and plateau during the third trimester. The levels of these hormones are of diagnostic significance in certain obstetric conditions and complications, but their exact impact on cutaneous physiology, as well as their influence on the immunology of the skin and the inflammatory response, is essentially unknown.

CUTANEOUS CHANGES COMMONLY ASSOCIATED WITH PREGNANCY

Although the influences that the individual hormones have on the skin are incompletely understood, it is thought that they are responsible, either primarily or secondarily, for many of the cutaneous changes that normally occur during pregnancy.

Pigmentation

The nipples, areolae, and external genitalia become hyperpigmented during pregnancy. The linea alba becomes the linea nigra. Occasionally, hyperpigmentation is noted in the axillae and the proximal medial portions of the thighs. The most noticeable pigmentary change during pregnancy is the development of a masklike hyperpigmentation of the face, known as chloasma or melasma, in more than 50 percent of women.

This tendency is exacerbated by sun exposure in susceptible individuals and also may be exacerbated by birth control pills in nonpregnant women. Additionally, preexisting nevi or ephelides frequently darken during pregnancy. The degree of hyperpigmentation tends to be related to the skin type of the individual, with lightly complected individuals developing less intense pigmentation. In all these instances, partial or, at times, complete regression of the hyperpigmentation usually occurs gradually after termination of pregnancy. The physiology of the hyperpigmentation appears to be related to the increased production of estrogens and perhaps to increased levels of progesterone or melanocyte-stimulating hormone.

Hair

Mild to moderate hirsutism is seen frequently during pregnancy. The hirsutism tends to resolve shortly after delivery or in some instances in the third trimester. After delivery, the resulting telogen effluvium may be severe, resulting in significant hair loss from 1 to 5 months postpartum. In these instances, regrowth, usually within 1 year, is the rule.

Connective Tissue

The most common change in connective tissue is the development of striae distensae over the abdomen, hips, buttocks, and sometimes the breasts .

Striae distensae occur in up to 90 percent of pregnant women. The exact cause of striae is unknown, although a combination of hormonal factors (e.g., adrenocortical hormones, estrogen, relaxin) associated with increased lateral stress on the connective tissue due to increased size of the various portions of the body is thought to be important. Striae distensae initially appear as pink to purple atrophic bands .

sometimes associated with mild pruritus. After delivery, they become pale and less apparent. Skin tags, also known as molluscum fibrosum gravidarum, often appear on the lateral portions of the neck and axillae during pregnancy and may persist after delivery.

Vascular

Hyperemia is physiologic during pregnancy. This, combined with a tendency toward vascular proliferation, results in a number of common cutaneous changes during pregnancy. Up to two-thirds of women develop palmar erythema and/or spider angiomas during pregnancy.

Vascular distention resulting in part from increased intraabdominal pressure is thought to be responsible for the edema and venous varicosities that commonly occur on the legs and feet. Hemorrhoids also occur for the same reasons. Vascular tumors such as glomus tumors or hemangiomas may appear or enlarge during pregnancy. The pregnancy tumor of the gingiva (i.e., the granuloma gravidarum or pregnancy epulis) is a pyogenic granuloma that may appear in the second or third trimester and resolves shortly after delivery.