Chances of a premature birth are heightened with mothers who conceive when they are older or use reproductive technology, says Dr Ellis Hon Kam-lun, a professor of paediatrics at Chinese University.
'The more babies are conceived in multiple pregnancies [often the case with fertility treatments], the more likely they will be born premature,' he says. 'Given the limited size of the uterus, a woman might give birth prematurely because of the heavy burden.'
While premature births aren't preventable, women can take steps to reduce risks and complications.
Regular prenatal check-ups are critical, says paediatrician Dr Barbara Lam Cheung-cheung.
'If there's a problem with the cervix, or the mother has a history of miscarriage, there's a high possibility that she will give birth prematurely,' Lam says. Women with medical conditions such as high blood pressure can be treated to minimise the risk of premature birth.'
Medication can be given to the mother 24 to 48 hours before delivery, to minimise damage to the baby, Hon says.
'Steroids can be injected into the mother to boost the baby's lung function. For those who fail to catch the 24-to-48-hour window, we will inject medicine into the baby's lungs after birth. But for those born at 24 weeks, such post-natal treatment might not work as well as steroids injected before delivery. So it's important for a woman to visit a gynaecologist, who can help assess her chance of having a premature birth and take prompt action.'
Hon says expectant women should adopt healthy lifestyles: 'Those who give birth to underweight babies are often smokers, who may develop placental problems that hinder the babies from absorbing enough nutrients.'