Women who sleep on their left side the night before giving birth reduce their risks of a late stillbirth, research shows.
The study by bmj found that women who do not sleep on this side on the last night of their pregnancy double the risk of complications.
But the increased risk of suffering a late stillbirth is still small, the authors stressed.
Women who sleep on their left side put their absolute risk of late stillbirth at 1.96 per 1,000.
Those who sleep in other positions, such as on the right or on their back, may see a slight increase to 3.93.
They added that if this was confirmed in other studies it could be beneficial at a population level.
The research also revealed that women who sleep throughout the day during the last month or use the toilet once or less the night before could be more likely to have a stillbirth.
According to the report authors there has been little change in the stillbirth rate over the past 20 years.
The research, led by PhD student from the University of Auckland, Tomasina Stacey, said that the issue is still too common and is an important health issue.
Daghni Rajasingam, spokesperson for the Royal College of Obstetricians and Gynaecologists, said: "This small scale study looks at another possible factor, however, more research is needed into sleep patterns before any firm conclusions over sleeping positions can be made.
"In the meantime, women should speak to their midwives if they are concerned.
"All new research into the causes of stillbirth are encouraging and are a step forward in understanding why they happen and improving stillbirth rates in the future."
"One would assume if its published in the BMJ it is a solid piece of work. It does give you food for thought, especially as there has been little change in terms of still birth figures for quite some time" - John Kelley
"I found myself checking the calender to see if it was April 1st. Awwww c'mon - how did they research this? You wouldn't know if it was the night before you gave birth - until you'd given birth, and then who can remember what position they slept in the night before. Does anyone know what position they sleep in? You're asleep at the time, so how would you know?" - Pat Allen, Cardiff