Every lunchtime during the week Wu Xiaoling has to rush home, pedaling her bicycle madly for 15 minutes, so she can feed her 9-month-old son. That done, she cycles back to work and has no time even for that Chinese specialty the quick desktop nap.

She is delighted that her second child is also a boy, which means her 6-year-old son's clothes and toys can be handed down to his brother.

During her latest pregnancy, Wu says, she underwent more medical examinations than she did during her first pregnancy, anxious about herself and her son, and felt much more tired in the first month of confinement after giving birth to the second son.

Wu, 36, who works in a government institution in Beijing, says: "It's much more stressful physically and mentally looking after kids than it was 20 or 30 years ago. For safety's sake you really do have to watch them around the clock. For example, there are many more electrical appliances and power points around the home than there used to be."

She recalls that when she was 5 or so she would play with other children in the neighborhood, but she is worried about letting her son have the free rein she did because these days there are far more cars and a lot more strangers about.

In all, raising a baby is more complicated and time-consuming than it used to be, and the duties involved in that huge task need to be delegated out to members of the family, she says.

Her mother and mother-in-law take turns staying at her place looking after the children and cooking. She buys all the ingredients for cooking on her way home and then plays with her sons. Her husband does household chores such as washing dishes and doing the laundry, and takes the elder son to piano and fencing lessons three or four times a week.

Grandparents who take care of two children during the winter holidays face an onerous task, especially because two boys are more difficult to handle than two girls, she says. The older boy makes a lot of noise when he is at home, so the baby can barely sleep. Concerns about electricity are overlaid with concerns that at any minute the baby could grab and swallow a Lego block that the older son may have inadvertently left lying around.

Wu says that since the most recent birth she has had no time for leisure and going out with friends. The elder son likes to play with her when she gets off work. She hardly ever gets enough sleep, she says, because she has to get up several times during the night to feed the baby. But things will be a lot better in three months when she stops breast-feeding, she says.

"I bought an English learning book and had planned to study it when I was on maternity leave, but I never had the time to even glance at it."

The family now spends double what it used to on food, about 4,000 yuan ($580) a month because of the extra food for the baby and nutritional food for the mother in the lactation period.

For those with two children who live in big cities, the financial pressure does not stop there.

Wu and her family live in an 80-square-meter two-bedroom apartment, and in the area where they live residential space sells at an average of 100,000 yuan a square meter.

If Wu and her husband wanted to employ a nanny they would be unable to house her because they have no spare room, she says, and they are reconciled to having to find a bigger place sooner or later. Another option is to rent or buy another small house nearby. But their parents would have to sell their homes in Beijing for the deposit and her husband would have to find a much more higher paying job.

Wu says many of her friends' children are studying abroad or have done so, and she expects the same for her sons when they grow up but worries about the expense.

"They may not need so much money for overseas education, but as a mother I have to set aside money for the future. With two sons, the pressure is great."

Having two children has had at least one other positive side-effect on the family, Wu says: she and her husband quarrel less than they used to. That is because they are simply too busy looking after their boys to be concerned with trifling matters.

After painful recovery from two caesarean births, Wu says, she has become more straightforward and open-minded.

"There is no difficulty that I can't overcome."