By Vaudine England
BBC News, Hong Kong
The Hong Kong government has announced new rules to try to limit the number of pregnant women from mainland China coming to give birth in Hong Kong.
In mainland China, mothers must abide by the one-child rule
The women are tempted by Hong Kong residency rights, the chance to dodge China's one-child policy, and higher standards of medical care.
But Hong Kong mothers say the influx has strained medical facilities.
In future, any pregnant woman coming from China without a hospital booking will be turned back at the border.
The rules are due to take effect on 1 February.
Hospitals in Hong Kong are setting up a centralised booking system to give priority to local women, and impose a quota on the number of mainland mothers allowed in.
Charges for mainland women to give birth in Hong Kong will also be raised.
The territory's medical facilities have been greatly strained by the growing numbers of women arriving - often at the last minute - to give birth in Hong Kong.
More than 12,000 mainland women did so last year.
Chinese people born in Hong Kong automatically gain local residency rights, including to health and education.
Mainland mothers giving birth in the territory also avoid the restrictions of China's one-child policy, and believe Hong Kong's medical care is better.
Many of them have said higher prices and an extra trip to get a booking will not deter them.
Hong Kong mothers hope the new rules will prevent non-taxpayers from jumping the queue, but feel the only real solution is to change residency laws.
That, however, would require politically sensitive negotiations with China, to redefine the "one country, two systems" slogan governing Hong Kong's ties with the mainland.