BACKGROUND: Borderline personality disorder (BPD) is a severe mental disorder characterised by emotional instability, impaired interpersonal functioning and an increased risk of suicide. There is no clear evidence about how best to help women with BPD during the perinatal period. Perinatal Emotional Skills Groups (ESGs) consist of 12 group sessions, focussing on core skills in emotion regulation, interpersonal effectiveness, distress tolerance and mindfulness and how these skills can best be utilised during the perinatal period. Prior observational research has shown that perinatal ESGs may help women with BPD. We set out to test the feasibility of conducting a randomised controlled trial to investigate the clinical effectiveness of perinatal ESGs.

METHODS: A two-arm, parallel-group, feasibility randomised controlled trial of Perinatal ESGs in addition to Treatment as Usual (TAU) versus TAU for women aged over 18 years, who are likely to have a diagnosis of BPD and are either pregnant or are within 12 months of having a live birth. We will exclude women who have a co-existing organic, psychotic mental disorder or substance use dependence syndrome; those with cognitive or language difficulties that would preclude them from consenting or participating in study procedures; those judged to pose an acute risk to their baby and those requiring admission to a mother and baby unit. After consenting to participation and completing screening assessments, eligible individuals will be randomly allocated, on a 1:1 ratio, to either ESGs + TAU or to TAU. Randomisation will be stratified according to recruitment centre. Feasibility outcomes will be the proportion of participants: (1) consenting; (2) completing baseline measures and randomised; (3) completing the intervention and (4) completing follow-up assessments. All study participants will complete a battery of self-report measures at 2 and 4 months post-randomisation. A nested qualitative study will examine participants' and therapists' experiences of the trial and the intervention.

DISCUSSION: Evidence is lacking about how to help women with BPD during the perinatal period. Perinatal ESGs are a promising intervention and if they prove to be an effective adjunct to usual care, a large population of vulnerable women and their children could experience substantial health gains.

TRIAL REGISTRATION: ISRCTN80470632.