In this study, a questionnaire survey was conducted to find the relationship between preeclampsia (PE) and incontinentia pigmenti (IP). Using a questionnaire survey of 147 women whose children were diagnosed with IP, this study first investigated their clinical manifestations and complications during pregnancy. The manifestations included high blood pressure, proteinuria and edema after 20?weeks of gestation. Women with and without IP were separated into two groups, then analyzed accordingly. There were 45 mothers with IP in the case group and 102 mothers without IP in the control group. IP mothers who were pregnant with an IP fetus were at higher risk for hypertension, proteinuria, and edema during pregnancy as compared with non-IP mothers that carried an IP fetus. Out of these 147 mothers, 8 mothers with IP and 6 mothers without IP presented with new-onset hypertension during pregnancy (P =?0.024)，7 mothers with IP and 4 mothers without IP presented with new-onset proteinuria during pregnancy (P =?0.013)，and 21 IP mothers and 27 non-IP mothers presented with edema during pregnancy (P =?0.016). Although no statistical difference was observed, mothers in the case group were more likely to develop the above three symptoms concurrently (6.7% vs 2.0%; P =?0.168), and were more likely to be diagnosed with PE (8.9% vs 3.9%; P =?0.249). Our study revealed that the simultaneous occurrence of IP in the mother and fetus increased the likelihood of clinical manifestations associated with PE during pregnancy. ? 2019 Japan Society of Obstetrics and Gynecology.