LONDON (AP) — British Prime Minister David Cameron is calling for an urgent review of how pregnant women are handled by prisons in light of figures showing 100 babies spent time in prison last year.

He said Sunday it is "absolutely terrible" for the infants to spend time behind prison walls and suggested the government look at alternative approaches.

Pregnant women who give birth while incarcerated are typically placed in a mother and baby unit inside the prison for up to 18 months.

Cameron says some prison staff workers are able to make these environments pleasant but that better alternatives should be studied.

"Think of the damage done to the life chances of these children," Cameron said.

He plans a speech on prison policy Monday.