Technique gives hope to infertile

THE birth of more than 100 Hong Kong babies has been made possible by the assisted human reproduction unit at the Prince of Wales Hospital and some of the latest technology is allowing even more couples to realise their dream.

The first local baby to be born using a new method of injecting a sperm into an egg was delivered two weeks ago and doctors believe at least 60 couples a year could benefit from the technique.

It is far more precise than other methods of assisted human reproduction and gives hope to couples who have given up trying to have a baby using in vitro fertilisation (IVF) - mixing the sperm and eggs together outside the body.

The four-kilogram bouncing baby boy was the result of just one visit by the parents to the unit.

It was also only the eighth attempt at using the micro-manipulation method known as sub-zonal insemination (SUZI) at the unit.

Holding the egg still by suction, a $300,000 device pierces the embryo wall with a sharp needle and gently injects sperm into its fluid, making it easier for the sperm to reach the egg cell.

But the doctor who engineered the territory's first ''sperm injection'' baby will next month learn how to take the technique a stage further and perhaps increase its success rate.

Dr Tony Chiu Tak-yu will go to Australia to learn intra-cytoplasmic sperm injection (ICSI) in which the sperm is injected directly into the mother's egg.

The use of SUZI and ICSI is part of the unit's on-going attempt to refine and improve the precision of various assisted-conception procedures.

Since its own birth at the Lee Hysan clinical research laboratories at the Prince of Wales Hospital in May 1985, the unit has made significant progress in helping couples who fail to conceive by natural means.

The unit now treats more than 200 couples a year.

And, last November, the unit held a party to celebrate the 100 births conceived by assisted human reproduction technologies since its inception.

IVF technology has been developed jointly by the departments of obstetrics and gynaecology and of anatomy, with support from the chemical pathology department.

The unit has facilities for semen preparation, embryo culture, freezing and thawing of embryos, the transfer of embryos from in vitro culture to the patient, and the preparation of culture medium.

IVF and embryo transfer involves ovarian stimulation, retrieval of an egg, insemination and fertilisation of the egg, and replacing not more than four embryos in the uterus to avoid multiple births.

The first baby resulting from IVF at the Prince of Wales Hospital was born in August 1987 - a three-kilogram boy.

Three months later, the first baby resulting from gamete intra-fallopian transfer (GIFT) in Hong Kong, a boy weighing 2.7 kg, was born at the hospital.

GIFT involves the placement of sperm and egg into one or both fallopian tubes with fertilisation and embryonic development occurring naturally.

The technique provides an alternative to IVF in patients with normal fallopian tubes and has generally a higher pregnancy rate compared with IVF.

Ovarian stimulation, egg recovery and semen preparation in this technique are essentially the same as for IVF.

In 1988, the unit began to cryo-preserve, or deep freeze, human embryos and, in May 1990, the first set of twins derived from cryo-preserved or frozen embryos were born in Hong Kong.

The boy and girl, weighing 1.8 kg and 2.05 kg respectively, were six weeks premature but both were healthy and well.

Human embryos not needed for transfer during the IVF treatment cycle can be cryo-preserved at the unit and later thawed and transferred to the uterus during a natural menstrual cycle.

In February 1991, the first set of twins resulting from pronuclear stage tubal transfer (PROST) at the hospital were born.

The technique involves fertilising eggs outside the body followed by transfer of the pronuclear eggs into the fallopian tubes.

Meanwhile, the unit continues to make use of some the newest technology in the field of assisted human reproduction in a bid to help infertile couples who desperately want a baby.