Pregnant women who regularly have milk or yogurt with "good" bacteria may be less likely to suffer the late-pregnancy complication known as pre-eclampsia, a new study finds.

Pre-eclampsia occurs when a woman has a sudden increase in blood pressure after the 20th week of pregnancy. Other signs include protein in the urine and swelling in the face and hands.

The disorder, which affects about 5 percent of all pregnant women, can be dangerous if unrecognized: It may progress to the rare condition eclampsia, which can cause the mother to have seizures or fall into a coma.

In the new study, researchers found that of more than 33,000 Norwegian women who gave birth over six years, those who consumed probiotic milk or yogurt every day during pregnancy were less likely to develop pre-eclampsia.

Of those women, 4.1 percent developed pre-eclampsia, compared with 5.6 percent of women who did not consume probiotic food.