Asian women tend to seek fertility treatments at a later age after having tried on their own for a longer time- and this is what leads to them having a lower pregnancy rate compared with Caucasian women.

An Australian 10-year cohort study, published in the Journal of Obstetrics and Gynaecology Research in 2014, noted that "it is not Asian ethnicity but age and duration of infertility that explain the apparent difference in pregnancy rate" between Asian and Caucasian women.

In what is possibly the largest study of its kind, more than 2,500 patients who had their first fresh in-vitro fertilisation (IVF) or intracytoplasmic sperm injection (ICSI) cycle between 2001 and 2010 were looked at.

With IVF, the mother's egg and father's sperm are placed in a dish and they are allowed to fertilise naturally. ICSI involves manually injecting a single sperm into an egg.

All 522 Asian and 2,072 Caucasian women were managed by a single doctor in a private reproductive medicine clinic in Sydney, Australia.

On average, Asian women were older by two years, had endured a longer period of infertility prior to IVF or ICSI treatment and required higher total dosage of gonadotropin- medicine to stimulate the development of multiple follicles in the ovaries.

Asian women in the study produced fewer harvestable eggs and had a smaller number of embryos.

One of the five study authors, Australian fertility specialist Andrew Kan, said this showed that Asian and Caucasian women in the same age group react differently to the same amount of stimulating drugs.

He believes this is why Asian women had a higher number of embryos transferred to the womb to improve their conception rate.

In the study, 22.2 per cent of Asian women became pregnant after IVF or ICSI, compared with 30.6 per cent for Caucasian women.

About 15 per cent of Asian women successfully gave birth after each treatment cycle compared with 22.5 per cent for Caucasian women.

Singaporean Stefanie Koh, 41, sought medical help after trying for a baby for a year.

Still, it took her five years before she had her twin boys, now 21/2 years old, after her fourth IVF cycle.

She recalled being terribly frustrated then and had seriously considered adopting a child.

Her advice to other struggling couples is to seek fertility treatment as a means to becoming a parent.

"Focus on your goal," she said.