The potential effects on pregnancy outcome are “significantly bad” in the sense that untreated depression even in the absence of diabetes “increases low birth weight in offspring, increases the risk of premature birth, increases rates of pre-eclampsia, and increases neonatal irritability,” Dr. Miller said.

“Even in the absence of other confounding factors, if you compare newborns just a few hours after birth, born to mothers with untreated depression during their pregnancy as opposed to other newborns, you'll find excessive crying, difficulty with sleep, fussiness, and difficulty being soothed.”

Some of the ill effects of depression on diabetes could be related to the diabetes disease process itself, Dr. Miller said. For example, elevated cortisol is relatively common in depression and can affect blood glucose levels. Even so, she maintained that most of the effects of depression in women with diabetes appear to be due to decrements in diabetes self-care. “That's on every level: less adherence to diet and as a result, higher body mass index, less physical activity, more smoking, less self-monitoring of blood sugar levels, and less adherence to diabetic medication,” she said.

Dr. Miller discussed the telltale signs of untreated clinical depression and how those symptoms could influence diabetes outcomes:

**** Enduring depressed mood or anhedonic state. A woman with diabetes who is anhedonic “will have a difficult time caring about themselves to follow through with self-care for diabetes,” Dr. Miller said.
**** Changes in appetite and weight. This could involve increased or decreased appetite “and often an appetite for different kinds of foods—often very sugary foods—and changes in sleep that, in turn, affect changes in appetite and weight,” she said. “This could directly influence blood glucose control in diabetes.”
**** Psychomotor retardation. The resulting sense of fatigue or feeling of less energy brought on by this symptom could influence a person's metabolic rate and exercise level.
**** Feelings of guilt or worthlessness. “Some people just don't feel that they're worth the bother of diabetes self-care,” she observed.
**** Impaired concentration. This may result in the woman's inability to remember whether she took her insulin or oral hypoglycemic “and taking too much or too little as a result.”
**** Thoughts of death, including suicidal thoughts. Dr. Miller said it is not uncommon for people with diabetes to use insulin in a suicide attempt.

“Looking at all of those symptoms, it shouldn't surprise us that studies almost consistently find strong links between depression and diabetes,” she said. “Women who are depressed are more likely to develop diabetes as well as the converse. People with pre-existing diabetes are also more likely to develop depression.”