Rennie Gibbs, a 15-year-old from Mississippi, faces life in prison for having a miscarriage, resulting in the death of her unborn child. Gibbs lost her baby in December 2006 in a stillbirth when she was 36 weeks into the pregnancy.

Prosecutors noted her cocaine addiction as the driving force behind the case, even though there was no evidence to link the miscarriage with drugs.

Gibbs is the first woman in Mississippi to be charged with murder relating to the loss of her unborn baby. But her case is by no means isolated. Across the US more and more prosecutions are being brought that seek to turn pregnant women into criminals.

"Women are being stripped of their constitutional personhood and subjected to truly cruel laws," said Lynn Paltrow of the campaign National Advocates for Pregnant Women (NAPW). "It's turning pregnant women into a different class of person and removing them of their rights."

Bei Bei Shuai, 34, has spent the past three months in a prison cell in Indianapolis charged with murdering her baby. On 23 December she tried to commit suicide by taking rat poison after her boyfriend abandoned her.

Shuai was rushed to hospital and survived, but she was 33 weeks pregnant and her baby, to whom she gave birth a week after the suicide attempt and whom she called Angel, died after four days. In March Shuai was charged with murder and attempted foeticide and she has been in custody since without the offer of bail.

In Alabama at least 40 cases have been brought under the state's "chemical endangerment" law. Introduced in 2006, the statute was designed to protect children whose parents were cooking methamphetamine in the home and thus putting their children at risk from inhaling the fumes.