SATURDAY, Nov. 5 (HealthDay News) -- Pregnancy is safe for most women with stable lupus, a new study indicates.

Lupus is a chronic inflammatory disease that can affect many organs of the body and cause arthritis, fatigue and rashes. Lupus has been known to cause complications for pregnant women. The disease occurs mostly in women, often emerging in their 20s and 30s when many women want to have children.

In this study, researchers identified a few predictors of lupus-related pregnancy complications, but also found that most women with stable lupus had successful pregnancies.

The findings were to be presented Nov. 7 at the American College of Rheumatology annual meeting in Chicago.

The study included 333 women with lupus who were followed from their first trimester of pregnancy until three months after they gave birth. On average, the women's lupus was relatively inactive.

Poor outcomes occurred in 63 of the women, including 30 who delivered before 36 weeks or had newborns of small gestational size and 19 who experienced the death of the baby.

Ten percent of the mothers developed preeclampsia, 10 percent experienced mild or moderate flares of lupus at 20 weeks and 8 percent experienced a flare at 32 weeks. Severe lupus flares occurred in under 3 percent of women at 20 and 32 weeks.

The researchers found that the 20 percent of women who experienced pregnancy complications were more likely to have certain risk factors: higher levels of lupus activity; high antibodies that may increase the chances of developing a blood clot; increased lupus activity at 20 or 32 weeks of pregnancy; and poor overall health.

The fact that 80 percent of the women in the study had successful pregnancies should reassure women with lupus who want to have children, the researchers said. They added that their findings suggest these women be advised that the best time to become pregnant is when the lupus is stable and they are not experiencing a flare of the disease.

"This very large study including racial and ethnic minorities, provided evidence that women who conceived while their disease was stable or only mildly active had relatively infrequent flares during their pregnancies and delivered healthy babies," study authors Dr. Jill P. Buyon, a professor of medicine at New York University School of Medicine, and Dr. Jane E. Salmon, of the Hospital for Special Surgery in New York City, said in a college news release.

"This held true regardless of past disease severity or past kidney disease [a frequent consequence of lupus]. These findings inform women with lupus on how to best plan when to conceive to assure the most favorable outcome for themselves and their babies."

Because this study was presented at a medical meeting, the data should be viewed as preliminary until published in a peer-reviewed journal.

More information

The Lupus Foundation of America has more about lupus and pregnancy.