Depression during and after pregnancy may be linked to gestational diabetes, a new government study found.

Women in the study who reported feeling depressed early in pregnancy were more likely to develop gestational diabetes later in pregnancy compared with those who did not report depression early in pregnancy, according to the study, from researchers at the National Institute of Child Health and Human Development (NICHD).

The findings suggest that "depression and gestational diabetes may occur together," Stefanie Hinkle, a population health researcher at the NICHD and the lead author of the study, said in a statement. [9 Uncommon Conditions That Pregnancy May Bring]

In addition, the researchers found that having gestational diabetes may increase women's risk for developing depression after pregnancy: Women in the study who had gestational diabetes were more likely to develop postpartum depression compared with those who did not have gestational diabetes, according to the study.

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Gestational diabetes is a type of diabetes that occurs during pregnancy. When a person has diabetes, the body cannot properly control blood-sugar levels. During pregnancy, diabetes can put both the mother and the baby at risk; women can develop a high blood-pressure condition called preeclampsia, which can become life-threatening, and babies can grow too large within the uterus, which can make birth difficult.

In the U.S., 9.2 percent of women develop gestational diabetes, and postpartum depression affects 10 to 15 percent of mothers within a year of giving birth, according to the Centers for Disease Control and Prevention.

In the study, the researchers looked at data from about 2,800 women who were enrolled in the NICHD Fetal Growth Studies-Singleton Cohort, a long-term study that tracked women's health and the health of their babies, during and after pregnancy.

The women in the study filled out questionnaires in the first and second trimesters of pregnancy and at six weeks postpartum, indicating if they had any symptoms of depression. Based on these responses, the researchers calculated each woman's "depression score." In addition, the researchers reviewed the women's medical records to see if they had gestational diabetes.

Results showed that women with the highest depression scores in the first and second trimesters were three times more likely to have gestational diabetes than those women with lower depression scores.

In addition, women who had gestational diabetes were four times more likely to go on to develop postpartum depression compared with women who didn't have gestational diabetes, the researchers found.

The researchers noted that more research is needed to firmly establish the link between depression and gestational diabetes. The findings did not prove cause and effect, Hinkle said. However, previous studies have suggested that depression may have an effect on how the body breaks down sugar, which could lead to higher blood-sugar levels.

Until there's more information, doctors may want to keep an eye out for signs of gestational diabetes in pregnant women who have symptoms of depression, Hinkle said. "They may also want to monitor women who have had gestational diabetes for signs of postpartum depression," she added.

The study was published today (Sept. 19) in the journal Diabetologia.

Originally published on Live Science.