Salma (not her real name) was racked with guilt, self-loathing and anxiety about her four children's well-being while she was in jail.
She was incarcerated for close to five years for drug trafficking in 2010.
After she and her husband were arrested for drug offences, her children were split up and cared for by two different relatives.
The children were then between 20 months and 10 years old.
Salma, who was released last year, said: "I was a horrible mother as I caused my children to suffer. I had no news of them and I thought of them every day (when I was in jail)."
CAUSE FOR CHANGE
We thought if we could help to heal strained ties between mother and child, this would help the women to change for the better and stay out of trouble.
MS SALEEMAH ISMAIL, who co-founded the charity New Life Stories in 2014.
The 51-year-old housewife saw them only thrice in the first four years of her sentence - her second for drug offences.
Her children were too young to visit her on their own and volunteers took them to the Changi Women's Prison on Mother's Day.
It meant the world to her when volunteers from New Life Stories - a charity that helps incarcerated mothers and their children - visited her in jail regularly, encouraged her and updated her with news about her children.
They also taught her to read children's stories, taped her reading and passed the voice recordings to her children so they could hear her voice and know that she loves them.
Ms Saleemah Ismail, who co-founded the charity in 2014, said the biggest source of anguish for incarcerated mothers was being separated from their children.
"Some had no news of their children at all, while others said their children rejected them as they felt abandoned by their mums," she said.
"We thought if we could help to heal strained ties between mother and child, this would help the women to change for the better and stay out of trouble."
Ms Saleemah also realised that many of the inmates' children could not speak or read English when they started school, putting them at a serious disadvantage as they struggled with subjects taught in English.
So on top of getting the mothers to read to their children, volunteers visited thekids twice a week for two and a half years to read storybooks with them to help them learn English and pick up values the stories in the books impart, such as courage and perserverance.
She said: "We don't want these kids to be left behind in the educational system because of their mothers' incarceration."
Since the charity started its Early Reader programme in 2014, 37 women and 69 children have been on it.
Most of these women are divorced, unmarried or have had no contact with their children's fathers. Some also have husbands in jail. They have an average of four children each.
Many are behind bars for drug offences, said Ms Saleemah, and often, grandparents have to step in to look after the children.
She told The Sunday Times the charity plans to expand the programme next year but declined to share more information. Its other co-founder is Ms Melissa Kwee, chief executive of the National Volunteer and Philanthropy Centre. Ms Kwee co-founded New Life Stories in her personal capacity.
Ms Saleemah said the results of the Early Reader programme have been promising, with the children showing "considerable" improvement in their ability to read.
For example, Salma's 10-year-old daughter, Zizi (not her real name) used to struggle as she could not understand what her teachers were teaching but with the Early Reader volunteers' guidance, her English has improved significantly.
She told The Sunday Times she scored 46 out of 50 for a recent English test. Zizi, who lived with her aunt when her parents were incarcerated, said she was thrilled to hear her mother reading stories to her.
She said of her mother: "I missed her. At times, I forgot what she looked like so I imagined (her appearance). My younger sister always asked me, where's mother? I explained to her that she's in prison but she did not understand."
Another beneficiary Sue, 45, said she was surprised and proud to find that her two children, aged eight and nine, could speak and read English proficiently when she was released from jail last year after three years behind bars. It was her fourth jail term for drug offences.
She said she was overjoyed when her son, the eight-year-old, was awarded a good progress award in school recently.
When she and her husband, who was also caught for drug offences, were in jail, her parents took care of her children. Early Reader volunteers visited and read to her children every week.
Sue, who declined to give her full name as she told her children she was seriously ill in hospital to hide the fact of her imprisonment, said: "In the past, I never think about my children as I was addicted (to heroin). When I was in jail and with all that counselling, I missed my children so much and I told myself that I have to change and be a good and responsible mother."