Losing a pregnancy is always tragic.

It may be even more poignant when stillbirth occurs just a few weeks before the baby is due.

In economically advanced nations, this occurs in about three of every 1,000 pregnancies.

Now, a small study published in the British Medical Journal suggests that pregnant women could reduce this risk with a very simple step — sleeping on their left sides.

The study involved interviews with more than 150 women who lost apparently healthy pregnancies after 28 weeks of gestation or more.

The scientists also questioned more than 3,000 women with ongoing pregnancies. All the women were asked about their sleeping habits.

The results indicate that women who sleep on their left sides suffer about half the number of late stillbirths compared with women who sleep on their right sides or on their backs.

The scientists aren’t exactly sure why sleeping position would be such an important factor. But unrelated studies have suggested that lying on the left side provides better blood flow to the uterus, meaning more oxygen for the baby.

But there are no definitive answers yet. The researchers cautioned that their findings could be subject to error. For one thing, the women weren’t monitored as they slept, so they could have changed position without realizing it.

Nonetheless, the researchers say follow-up studies are urgently needed.

People spend about one-third of their lives asleep. This means that a fetus will stay in the same spot for a long time while its mother rests, that’s bad news for baby if sleeping position plays as significant a role as researchers think.

Obstetric science may never eliminate stillbirths completely, but this looks like one area where aggressive research might pay big dividends — healthy babies, and happy families.