T.V star Louis Theroux has spent time in a Croydon hospital, filming a documentary following four mothers suffering mental illness following the birth of their children.

Filmed at Bethlem Royal Hospital's Mother and Baby Unit, the documentary explores what lies behind mothers' recent crises and discovered how staff on the unit care for them.

Mothers are admitted with their babies and supported by a range of professionals including psychiatrists, psychologists, mental health nurses, nursery nurses, midwives and other professionals.

Treatment can include a range of therapies such as psychotherapy, as well as medication.

Dr Gertrude Seneviratne, Lead of the Perinatal Mental Health Services at South London and Maudsley NHS Foundation Trust, said: “I want to say thank you to the women and their families who have taken part in the documentary, their contribution helps to shed light on these important issues and reduce stigma around perinatal mental health.

“The arrival of a baby should be the happiest time in a woman’s life, but for some women this is not the case - our research shows that one in four women experience mental health problems during pregnancy or shortly after the baby is born.”

Titled 'Louis Theroux: Mothers On The Edge', the documentary airs on BBC Two at 9pm May 12.

Deborah Griffin, Clinical Service Lead on the Mother and Baby Unit said: “The crew were with us through some very challenging times and were extremely supportive to the team and the mums on the ward.

“The documentary is sensitively made and gives a rare, compassionate but enquiring insight into the world of perinatal mental health, the complexity of the difficulties that the women admitted to us are experiencing and highlights the impact of social media on the pressure women experience to be the perfect mother when they are struggling to manage.

“It also gives a message of hope, as we see our mums get better and return home with their babies.”