The eggs and sperm were combined and placed in incubators, devices that have tightly controlled temperature, oxygen, carbon dioxide and humidity levels to enable fertilisation. After about 18 hours, the eggs were fertilised and left for about 48 hours while cells start to divide.

At the end of two days, the fertility specialist would select "good" embryos for implantation into Patsy's womb.

But the embryos implanted into Patsy's womb failed to develop, and she did not become pregnant. Doctors told the couple the quality of the embryos were poor.

For four years, Patsy endured four egg retrievals and six failed implantations.

According to Dr Milton Leong Ka-hong, founder and reproductive medicine specialist of the IVF Centre at the Hong Kong Sanatorium and Hospital, the standard embryo selection process is relatively archaic. Doctors can only rely on the appearance of the embryos to determine whether or not they are healthy.

"One can only look at the shape and size of the different cells to see if there is any fragmentation, any abnormal particles inside the embryo," says Leong.

This method has been used since IVF was introduced 25 years ago. But judging an embryo based on appearance is like a beauty contest, says Leong. There is no telling what the genetic or functional quality of the embryo is.

Once the embryos are implanted into the womb, communication between the embryos and the mother must be established so that the mother's body will start to nourish the embryo with oxygen and nutrients, as well as take away metabolic waste from the developing embryo. If the embryo does not receive support in six to eight hours, the baby cannot grow, says Leong.

This process is not as smooth as we would like, he adds. A study found that for every woman who becomes pregnant, another would have become pregnant but lose the baby within the two weeks from ovulation to menstruation. "Humans are not very prolific in reproduction," says Leong.

Early this year, Henry and Patsy moved to Hong Kong. After they had settled in, they felt ready to give IVF one more try. They turned to the IVF Centre.

The centre had just acquired a new incubator, which had only recently become commercially available. It was the first in Asia to get one. This device, called an embryoscope, provides the controlled environment of an incubator, but also features a time-lapse camera that captures the development of embryo.

In other words, fertility specialists such as Leong can now observe the division rate of the cells in the embryo. They can see whether the cells are dividing at a normal rate and this provides a crucial edge in the selection of borderline embryos, explains Leong.

With conventional incubation methods, embryos are taken out once a day, at most, for observation under the microscope. That is because the transfer of the embryos from the controlled environment of the incubator to the laboratory environment can unsettle the embryos, says Leong. Sudden shocks are not conducive to the delicate process of embryo development.

So, given Henry and Patsy's lack to success with IVF, it was thought the embryoscope could provide an edge in producing a successful pregnancy. Patsy underwent another egg retrieval. This time, her womb yielded 13 eggs, out of which only eight were mature. This was considered a reasonable response, given her age.

Two of the immature eggs were matured in the laboratory, and eventually, seven eggs were fertilised. However, as was consistent with the couple's past experience, by day three, only four eggs remained viable.

Using the videos provided by the embryoscope, Leong was able to identify two good embryos and one borderline embryo for implantation. This time, Patsy became pregnant.

Leong says IVF produces a pregnancy rate of only 45 to 55 per cent. But as new technology develops, new tools such as the embryoscope can give couples who have experienced multiple failures with IVF an edge in their quest to have a baby.