You are not permitted to download, save or email this image. Visit image gallery to purchase the image.
NSW's controversial "Zoe's law" bill will open the door to women being prosecuted for smoking or drinking during pregnancy, protesters fear.
The legislative changes currently before the state's upper house would make it a criminal offence to destroy or harm a foetus after it reaches 20 weeks or 400 grams.
The bill was named in honour of the unborn child of Brodie Donegan, who was hit by a drug-affected driver on Christmas Day in 2009
Zoe was stillborn.
But Ms Donegan was the only victim recognised under current NSW law, which does not grant a foetus personhood.
About 200 people gathered in Sydney's Martin Place on Sunday were urged to write to members of the NSW Legislative Council before the bill is voted on in the upper house by the end of March.
A Sydney University obstetrics expert, Kirsten Black, told protesters she was concerned a mother-to-be who refused to undergo a procedure - for instance, a woman whose baby was presenting in the breech position but did not want to undergo a caesarean section - would be open to prosecution.
"This is not far-fetched. A Utah woman was charged with murder when she refused to undergo a caesarean section for her twins, and one died at birth," Dr Black said.
And she feared the proposed bill would pave the way for prosecutions aimed at woman who failed to follow medical advice throughout their pregnancy.
"I worry that this bill could open up the possibility of women being prosecuted for drinking, smoking and taking drugs during their pregnancy," Dr Black said.
"Whilst medical practitioners would urge women to make informed choices during pregnancy in the best interests of both their own health and that of their offspring, few if any would support a legal compulsion to follow medical advice."
The bill includes provisions designed to protect pregnant women, medical practitioners from prosecution and preserve abortion access.
But Julie Hamblin, a lawyer who specialises in health, told the crowd she was not convinced these provisions would be effective.
"The people who support Zoe's Law will say, correctly, that the bill has an exemption for medical procedures and it has an exemption for things done by or with the consent of the woman - so they argue that doesn't affect abortion," she said.
"As a lawyer, I simply don't believe that's true."