Patients with both, migraine and endometriosis, present the case-group, while women with endometriosis without migraine serve as controls. The primary endpoint is endometriosis stage confirmed by laparascopy compared to the control group. Further points to compare between groups are infertility, dysmenorrhea, dyschezia, dyspareunia, number of operations, family history with first-degree relatives, and age of first symptoms for both conditions and age at first operation.

Secondary endpoints to evaluate in percentages within the migraine group are migraine frequency, migraine aura/non-aura, age at migraine start, hormonal migraine, family history, treatment response, response to prophylactic agents, localization, types of aura and triggers. Other medical conditions and comorbidities like depression will be noted as well as response to Dienogest treatment.

In the questionnaire we will ask 62 Questions overall. The Questions for endometriosis are based on a questionnaire from the world endometriosis research foundation and to evaluate the severity of the migraine we will use the MIDAS (Migraine Disability Assessment) questionnaire (8).

Inclusion Criteria:

• Premenopausal women aged 18-55 years, at time of operation
• Endometriosis confirmed with surgery and histologic staging (Report of the surgery available)
• For the cases migraine needs to be confirmed during the interview according to the IHS criteria.

Exclusion Criteria:

• Inability to perform the interview (insufficient knowledge of language, psychological disorder, dementia)

From our database of operated endometriosis patients ranging from 2016-2020 100 women will be identified within the first phone call as cases with endometriosis and migraine and the threefold number (n=300) as control with endometriosis only.