BEIJING - At 60, Ms Sheng Hailin took on a challenge few people have faced. She had twin girls in 2010, which makes her the oldest person in China to give birth.

Now 64 and the mother of two four-year-olds, it is not an achievement of which she is proud. She chose in-vitro fertilisation (IVF) after her only child Tingting and Tingting's husband, died in 2009 of gas poisoning. Tingting was 29.

Her death left Ms Sheng and her husband as one pair among more than a million "orphan parents", in a country where parents traditionally rely on their children to take care of them when they get old, Global Times reported.

Almost unable to bear life without her daughter, Ms Sheng decided to have another baby in her old age.

"The newborn could carry on the life that my daughter left," Ms Sheng told the Beijing News.

It is estimated that 76,000 single-child families lose their child annually, according to the Ministry of Health. China's family planning policy, introduced in the late 1970s but relaxed last year, restricted most families to one child.

Traditionally children are considered the most important thing in the Chinese family. The loss of a child has put many orphan parents in a dilemma: to have another child in their old age or continue a painfully childless life.

Ms Sheng, originally from Anhui Province, gave birth to her first daughter at 31.

After seeing her beloved daughter marry, Ms Sheng thought she could live happily after her retirement as administrative chief of a local hospital. Her daughter's death broke the whole family, Global Times reported.

"We gave her the best, we gave her everything we had. I didn't know how to live without her," she said.

Ms Sheng said she was so overwhelmed she wanted to kill herself.

She bought a tomb next to her daughter so that she and her husband could be buried close to her. Her relatives talked her out of it.

Then she thought about adoption or using a surrogate mother, but neither choice seemed right for her. Eventually, she decided to take the risk and have another baby herself.

Having a child at 60 is risky, both to the mother and to the children, more at risk of birth defects as a result.

A Spanish woman named Maria del Carmen Bousada Lara, who had twin boys at 66 in 2006, is the oldest woman ever to have given birth. She died of cancer three years later, leaving her children orphans.

Ms Sheng and her husband consulted gynecologists, and they all told her to give up due to her age. It wasn't until July 2009 when they were accepted at the No. 105 Hospital of the People's Liberation Army that she started to have hope.

While undergoing IVF therapy, Ms Sheng had to go through rounds of treatments that made her constantly feel sick and tired. After three months of treatments, Ms Sheng started to menstruate again.

"I was under great pressure, and whenever I bought a sanitary pad I would cry like a baby," she said.

Soon she found out she was pregnant again. "The first time I was told I was going to have a baby, I was full of joy. This time, I was full of sadness.

"I cried constantly. I felt so sorry for myself. I shouldn't be living like this," she said.

In May 2010, she gave birth to Zhizhi, who weighed 1.85 kg, and Huihui, 1.45 kg. Both names mean "wisdom" in Chinese.

New children brought hope and happiness to the broken family. Ms Sheng said she felt she was ready to be a mother again.

"I've been through a lot. I am a more experienced mother now."

Ms Sheng's story made headlines in the media. She said her case cannot be easily copied.

"Many women who also lost their child came to ask me for advice, but reality scared them away."

By reality, she means the amount of quality time they could spend with their children, and the problems of finance and education.

Up to 50 percent of orphan parents are living at the minimum poverty level of 1,200 yuan (S$25) a month, and 60 percent suffer depression, according to a study by the Chinese Academy of Social Sciences.

"I hope these mothers can be stronger. It is easier to kill yourself than to have another baby," she said. "If they don't have money and energy to take care of the baby, they'd better not do it."

Ms Sheng returned to work 100 days after her babies were born. She has been travelling around the country giving health lectures.

At 64, Ms Sheng said she is no longer able to take care of two babies by herself. She hired a nanny at 10,000 yuan a month. She said she feels guilty not spending time with her babies, but she has to face reality.

The government has issued financial support for these families. Urban women older than 49 get 340 yuan a month, while rural women get 170 yuan. That is far from enough. Many orphan parents call for more compensation.

Ms Sheng does not know how much longer she can continue working. She plans to write a book when she is too old to work.

The family also faces prejudice and misunderstanding. When they take the children out in public, people think they are the grandparents.

"I prepared myself for this day. I learned I was pregnant. I am not ashamed of my choice," she said.