A new research has suggested that "boring and repetitive" household chores increases the odds of giving birth untimely.

Regular work out, however, is good for both mother and unborn child.

According to reports, the research involved facts amassed from around 12,000 new mothers about how much they had worked out during gestation comprising daily chores.

The results showed that mentally unstimulating work, comprising doing jobs around the house day-in day-out, raised the risks of giving birth at least three weeks early by around 25%.

Although it isn't clear why, scientists think that it may be that boring tasks increase levels of stress hormones involved in triggering labour.

The research, released in the journal Perinatal Epidemiology, also threw up some other interesting results.

Again it isn't clear why, but may simply be that those who work through pregnancy are healthier in general.

The research also disclosed that sedentary lifestyles increased the chances of having an underweight baby, whereas light and appropriate exercise routines did no harm to either mother or unborn baby.

Researcher Hajo Wildschut, of Erasmus University in Rotterdam stated, "Pregnancy is not a disease. In fact, most women who are pregnant are healthy and most of them are being delivered of perfectly healthy babies. Women who are healthy and do not have pregnancy complications should not restrict their activities in order to achieve a better pregnancy outcome."

Specialists said that in the majority of cases, work out during pregnancy is safe, however, mothers-to-be are advised to avoid sports which needs physical exertion.

Patrick O'Brien, a consultant obstetrician at the Royal College of Obstetricians and Gynaecologists. Stated, “Exercise is good in pregnancy, it keeps you aerobically fit, it keeps your weight under control, it probably reduces the chances of difficulties and it makes it easier to deal with the birth and after wards.” (With Inputs from Agencies)