To explore the relationship between the menstrual cycle and mental health-related symptoms in women admitted as psychiatric inpatients. To explore the acceptability and feasibility of enquiry. Background: Despite the increasing global burden of mental disorder among women* of reproductive age, there has been little focus in research or clinical practice on the role of reproductive hormones in the pathogenesis, maintenance and treatment of mental disorder in women. Yet a significant proportion of women are vulnerable to fluctuations in sex hormones (for example in the premenstrual or perimenopausal periods).

1. 1. 21 patients were asked a series of questions about their menstrual cycle by ward doctors, during their inpatient admission. Descriptive statistics were generated. Data from free text questions were analysed using thematic analysis.

2. 2. A focus group was facilitated by the ward occupational therapist on 1st November 2021, involving seven patients.

The project ran between November 2021 and February 2022. Mean age of respondents was 38 years and 57% (n = 12) were of Black ethnicity. 76% (n = 16) reported having a period in the last 12 months. Of these, 10 women felt their mental health changed throughout the month in relation to their menstrual cycle. Themes elicited from free text questions related to symptoms experienced during the pre-menstrual phase and included increased suicidality, anger, low mood and unusual experiences. Of the seven women who had not had a period in the last 12 months, over half (n = 4) reported menopausal symptoms. During the focus group those women who had gone through the menopause noted they had limited knowledge about it and how it may affect their mental health.

With regards to feasibility of enquiry, the focus group indicated that women would like to discuss their menstrual cycle, how it can affect their mood and additional support available. However, they would prefer this took place in a one-to-one setting outside of ward round, ideally with a female doctor.

A number of female psychiatric inpatients likely experience an increase in mental health-related symptoms pre-menstrually. Enquiry about menstruation is likely to be feasible in the inpatient setting, given it is done sensitively. Such enquiry could provide opportunities to discuss areas of concern to the patient and discuss specific issues such as menopause and pre-menstrual dysphoric disorder. It could also provide data for future research and guide the development of clinical practices that recognise the relationship between the menstrual cycle and women's mental health.