Smiling, Dr Charl Verwey appeases her. "She is negative" he says, pushing the results across the table, delivering the good news that successful prevention of mother-to-child transmission (PMTCT) has made possible.
"Oh thank God," the 25-year-old sighs as the relief shudders through her, her hands clasped in prayer position.
Back in the waiting room, another 30 mothers sit tense as their babies wail in staccato. It is their first chance to test their baby after receiving the life-saving drugs to prevent them from passing on AIDS to their children.
While transmission of HIV from mother-to-child in the developed world has largely been eliminated through the use of anti-retrovirals, thousands of children in countries like South Africa are still born infected.
Getting treatment to pregnant mothers has been one of the biggest battles in South Africa, publicly lambasted at the World AIDS Conference in Toronto two years ago for its approach to treating the pandemic.
After refusing to provide pregnant mothers with nevirapine until a court order in 2002, South Africa took two years to implement a World Health Organisation recommendation and provide improved dual therapy -- the drug AZT in addition to nevirapine -- to pregnant mothers.
"You can see the difference between the old treatment and the new treatment," says Verwey, who is fortunate enough to deliver mostly good news to the mothers in his waiting room at Johannesburg's Coronation hospital.
The hospital, the only mother and child facility in the Gauteng province, delivers 10,000 babies a year. A sample 45 mothers whose children tested shortly after the new guidelines were rolled out, showed only two were positive.
"It is the one area in HIV where we could see the immediate product of HIV prevention. Where we can give more good news than bad news," says paediatrician Ashraf Coovadia.
The new PMTCT guidelines were adopted in February after much pressure from AIDS activists, another victory in recent years for a country whose government was accused in Toronto of being "obtuse, dilatory and negligent about rolling out treatment."
The then UN special envoy for AIDS in Africa Stephen Lewis told the conference the government would never achieve redemption for theories were "more worthy of a lunatic fringe than a concerned and compassionate state."
Controversial Health Minister Manto Tshabalala-Msimang, known as Dr Beetroot for her championing of a diet of vegetables to combat the disease, was widely condemned after opening the South African stall displaying a selection of beetroot, garlic and vegetables.
However heading to Mexico, for the 17th International Conference, South Africa is in a much different place as the criticism spurred it to launch a new national AIDS plan and national AIDS council.
"Certainly garlic and beetroot are not part of the National Strategic Plan," said Coovadia, referring to what he called a "major embarrassment."
The NSP aims to reduce transmission from mother and child, which varies from eight percent in the Western Cape to 22 percent in Kwazulu-Natal, to five percent nationwide and cut all new infections in half by 2011.
However Treatment Action Campaign spokesman and deputy head of the South African National AIDS Council Mark Heywood says meeting treatment targets, and improved prevention, are still far off.
"We don't know how many people are on treatment, and that is a disaster in itself, government only knows how many people have been started on treatment, which was about 480,000 in June," he told AFP.
"But there are certainly well over a million people in need of treatment."
South Africa has the world's highest rate of HIV with some 5.5 million of the 47 million population affected by the virus.
"Compared to Toronto we are in a completely different political environment around AIDS," said Heywood.
"I don't think there is going to be any repeat in Mexico of the kind of anger seen in Toronto."