Introduction Surveillance data from Confidential Enquiries shows that women who become pregnant with pre-existing health conditions are at risk of poor outcomes, and those that have multiple medical problems are at greatest risk. Our understanding of the socio-demographic characteristics, associated medical and obstetric morbidity and pregnancy outcomes for this group is limited at present. Objective To describe the socio-demographic, medical and pregnancy characteristics of all women with multiple medical problems giving birth at a tertiary hospital in 2016, and to compare their outcomes with all women giving birth in the same period. Methods A comprehensive search of the Electronic Patient Record system was conducted to identify all women giving birth in 2016 at a tertiary hospital. The prevalence of multiple medical problems in pregnant women, defined as two or more known pre-existing conditions, was estimated with 95% confidence intervals, and, their sociodemographic, medical and pregnancy characteristics and outcomes compared with all other women in the cohort. Factors associated with poor outcomes were explored using logistic regression. Results 2004 women with multiple medical problems were identified amongst a cohort of 8121 women giving birth (prevalence of 25%, 95% CI 24–26%). Women with multiple medical problems had a median age of 35 years (IQR = 27–35 years) and nearly three quarters were multiparous (73%). Women with multiple medical problems gave birth at a median gestation of 39 + 5 weeks (IQR = 38 + 5 − 40 + 5 weeks). Data collection is ongoing, but will be complete by the time of presentation. Discussion These data from a tertiary obstetric unit highlight the high prevalence of multiple medical problems amongst women giving birth. Further research is needed to understand how maternity care can be best structured and delivered, taking into account the varying severity and impact of these conditions, to optimise maternal and neonatal outcomes.