Toronto, Jan 30 (Inditop) Mothers with diabetes and hypertension are much more likely to deliver pre-term babies, says a Canadian study.

According to the study, mothers over 35 are much more likely to give pre-term births.

The study by the Canadian Institute of Health Information says one in seven children – of the total 54,000 – born in 2006-2007 was delivered pre-term or small for their gestational age (SGA).

In a release Thursday, the institute said more women were delivering pre-term babies because of various genetic and social factors today than previously.

It said the Canadian pre-term birth rate (born before 37 weeks of gestation) has risen 8.1 percent from 6.6 percent the early 1990s.

On the positive side, the study said, the rate of SGA births (babies born with a weight below that for their gestational age and sex) was 8.3 percent, down from 11 percent in the early 1990s.

Institute vice president Jean-Marie Berthelot said: “Factors such as delayed child bearing and use of reproductive technologies are likely contributing to a greater number of multiple births and pre-term deliveries; while a lower smoking rate, for instance, may be contributing to a decline in babies born underweight for their age.”

The study found while biological factors played a role in pre-term births, social factors were dominant in SGA births.

The study found that “mothers who were diagnosed with hypertension and/or diabetes were up to six times more likely to deliver a pre-term baby compared to women without those conditions”.

It also found that mothers aged 35 and above had a pre-term birth rate of nearly 10 percent, compared to eight percent for those aged 20 to 34.

“We have known for some time that conditions such as hypertension and diabetes increased a woman’s chance of delivering pre-term, but it was difficult to quantify just how big a role these risks played,” said pre-term baby care expert and Calgary University paediatrician Reg Sauve.

“With the understanding that chronic conditions can increase the chances of having a pre-term birth sixfold, additional management of these conditions throughout a pregnancy becomes a vital step in limiting the instances of pre-term births,” he said.