Figures obtained by the Liberal Democrats show that since 2013 there have been 104 pregnant women in prison.
Of these, 37 were given sentences of less than 12 months and 31 gave birth while in prison.
The party’s justice spokesman, Liam McArthur, urged the Scottish government to press ahead with its plan to introduce a presumption against prison sentences of less than 12 months.
He said: “The fact that 37 expectant mothers have been given destructive short-term sentences in recent years should have alarm bells ringing.
“All the evidence shows that short-term sentences don’t work and are less effective than robust community-based disposals in reducing reoffending.
“Rates of reoffending among those who have served short stints in prison are sky high.
“That is why Scottish Liberal Democrats have consistently urged the Scottish government to introduce a presumption against sentences of less than 12 months, something ministers now accept would be a positive step.
“If, in the process, it means more pregnant women pay for any crime they have committed through robust means short of prison then that has to be in everyone’s interests.”
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A Scottish government spokesman said: “Reducing the use of ineffective short-term imprisonment and increasing the use of robust community sentences, is part of our smarter approach to tackling offending.
“That is why we have announced our intention to extend the presumption against short custodial sentences from three months to 12 months or less.
“Our new female custodial estate is designed to support family contact. Dedicated mother and baby facilities will be provided in the national facility, HMP Grampian and both community custodial units for those women who need them.”