Tens of thousands of pregnant mainlanders come to Hong Kong to give birth every year, taking up limited beds in maternity wards and pushing up delivery costs.
The problem is expected to peak in the Year of the Dragon, which comes every 12 years in Chinese astrology and usually results in a baby boom.
"We didn't plan for a Dragon baby," says 38-year-old Michele Lee, who is expecting her second child, a girl, in April.
"It was exciting when we first found out the news but very soon that excitement turned into worry about whether we'll get a place in hospital."
Hong Kong women have recently taken to the streets in protest over the influx of mainland Chinese mothers to the semi-autonomous former British colony.
Having their babies in the glitzy -- and relatively free -- southern city entitles the child to rights of abode and education, while providing a loophole the size of Victoria Harbour to China's one-child policy.
Lee says she tried to book a maternity bed at her gynaecologist's hospital soon after she found out she was pregnant, but it was already too late.
"I couldn't get my preferred private hospital to deliver even though I'm willing to pay and both me and my husband are Hong Kong residents," she says.
"Some friends told me I should start registering my Dragon baby girl for kindergarten -- it's like a fight for hospitals, a fight for schools. I have to remind myself to take it easy."
Mainland mothers accounted for 38,043 out of 80,131 births in Hong Kong last year. In the last Year of the Dragon in 2000, the number of births jumped 5.6 percent from the previous year, according to official data.
In anticipation of a baby boom the government has tightened entry rules, stepped up border controls and capped hospital places for mainland mothers.
Mainland women have reportedly taken to smuggling their precious cargoes into the territory under baggy clothes, or renting Hong Kong apartments in the early stages of pregnancy to avoid detection.
Some desperate women have even resorted to waiting until the last minute to force their way into Hong Kong emergency wards. Hospital authorities say emergency births tripled last year.
"The issue is far more complicated than we imagine," says Cheung Tak Hong, head of the obstetrics department at Hong Kong's Prince of Wales Hospital, a government hospital near the Chinese border.
"The system just cannot cope. The increase in the manpower and facilities just cannot catch up with the demand from China. There are far too many pregnant women from China coming to give birth in Hong Kong."
The doctor, who is a spokesman for the Hong Kong Obstetrics Concern Group, says mainland women are putting the lives of themselves and their babies at risk.
"They have no bookings, we don't have their records, we don't know them beforehand and all of a sudden they come here in advanced labour. That puts a lot of pressure on our staff," he says.
"I have no negative viewpoint about them because many years ago Hong Kong people were doing the same thing," he adds, referring to the number of local women who went abroad to have children before the city's 1997 handover to China.
"We hoped to give our children a better future, better opportunities," Hong says.
"That's why I understand why mainland women come to Hong Kong. That's why I am not saying it's wrong, it's just that we cannot cope with this number."
Public hospitals have seen a spike of about 15 percent in bookings for maternity beds this year, and total deliveries in all hospitals are likely to surge to 100,000, he predicts.