Striae gravidarum (SG), commonly known as “stretch marks,” are a common cosmetic concern for many parturients. Usually developing after 24 weeks’ gestation, they consist of erythematous or violaceous bands on the abdomen, breasts, buttocks, hips, and thighs that eventually fade to skin-colored or hypopigmented lines. Because the cause of SG remains unknown, risk factors were sought in a cross-sectional study of 110 primiparous women who delivered their infants at a private teaching hospital during a 6-month period of 2005. The presence and severity of SG on the abdomen, thighs, and breasts were determined in the postpartum period by one of three researchers using a scale developed by the research team. SG involving less than 25%, 25% to 50%, and more than 50% of the affected part of the body were rated, respectively, as mild, moderate, and severe.
SG developed in 67 the 110 women studied (61%). The abdomen was affected in nearly half the women studied, and the breasts and thighs in about one-fourth each. The three grades of severity were about equally represented in women with abdominal striae, whereas more than two-thirds of striae on the breasts and thighs were rated as mild. Women who developed SG were significantly younger than those who did not, and they had gained significantly more weight during pregnancy. Both body weight and gestational age at delivery correlated strongly with the risk of developing moderate or severe SG. The risk of SG was not influenced by Fitzpatrick skin type (based on the cutaneous response to solar exposure), socioeconomic status, smoking status, fetal gender, family history, or the use during pregnancy of creams or lotions intended to prevent SG. A family history of SG did predict moderate to severe SG in affected women.
While some of the risk factors for SG are not modifiable, others - such as weight gain during pregnancy - are potentially controllable. Future research on preventing SG should look closely at the prophylactic use of creams and lotions.