Pigmentary demarcation lines associated with pregnancy.

We report three cases of pigmentary demarcation lines associated with pregnancy. In addition, we reviewed 19 cases including our 3 cases, which were reported in Japan. Most cases occurred during the latter period of pregnancy (after the seventh month), and the pigmentation faded spontaneously or disappeared a few months after delivery in all cases except one. Pigmentary demarcation lines are classified into five groups (types A-E). Of the 19 cases we reviewed, 2 cases showed lines of both types A and B, whereas all the other cases showed type B lines. Although there have only been 29 cases of pigmentary demarcation lines associated with pregnancy reported to date, before ours, we experienced 3 cases within 3 months, therefore it is possible that many such cases are overlooked. Pigmentary demarcation lines are mainly a cosmetic problem. Two of our three cases presented to obstetricians initially. We suggest that dermatologists should be aware that pigmentary demarcation lines may be associated with pregnancy.