Women with a history of severe bipolar disorder have a much higher chance of giving birth to their children prematurely, a new study finds. People with bipolar disorder are affected by one of several conditions that produce episodes of mood variations that swing from a manic state to a depressed state. Premature childbirth is a term used to describe childbirth that occurs before a woman reaches the end of her 37th week of pregnancy. In a study published in late 2014 in the American Journal of Obstetrics and Gynecology, a team of Canadian researchers sought to determine if pregnant women with a history of severe bipolar disorder have increased chances of delivering a child prematurely. Bipolar Disorder Most adults are aware of bipolar I disorder, a condition known informally as manic depression. People affected by this mood disorder typically experience episodes of an overexcited, extreme state known as mania, as well as separate episodes of depression symptoms similar or identical to those associated with major depression (major depressive disorder). However, bipolar I disorder is just one form of bipolar illness. Other recognized conditions include bipolar II disorder, which produces episodes of depression and episodes of a less severe form of mania called hypomania; cyclothymic disorder, which produces episodes of relatively minor depression and episodes of hypomania; and an illness called substance\/medication-induced bipolar and related disorder. Another highly damaging bipolar illness, known as rapid-cycling bipolar disorder, produces a minimum of four manic and\/or depressed episodes a year. Once it arises, a bipolar illness typically remains an issue for the rest of a person\u2019s life. However, he or she often experiences no adverse effects while not in the midst of an episode of mania or depression. Population groups with increased odds of developing a bipolar disorder include people in their first years of adulthood and people in their last years of adolescence. Premature Childbirth Premature childbirth is dangerous because many key organ systems only reach their full functionality when a developing child goes through the final phases of normal gestation. Specific health problems associated with being born prematurely include impaired hearing and\/or vision, problems with the mother\/child feeding process, impaired breathing, cerebral palsy and altered post-natal development. A number of factors can increase a woman\u2019s chances of experiencing premature childbirth, including drinking or smoking while pregnant, abusing drugs or medications while pregnant, being a teenager or older woman, developing high blood pressure while pregnant, having an African American racial\/ethnic background, carrying multiple developing children and having a past experience with premature childbirth. Figures compiled by the federal Centers for Disease Control and Prevention indicate that roughly 11 percent of American infants are born prematurely. Bipolar Disorder Increases the Risks In the study published in the American Journal of Obstetrics and Gynecology, researchers from the University of Toronto, Sunnybrook Health Sciences Centre and several other Canadian institutions used data gathered from more than 430,000 women pregnant with a single child to explore the impact that a personal history of bipolar disorder has on a woman\u2019s chances of giving birth prematurely. A total of 1,859 of these women had a history of bipolar disorder severe enough to require some form of hospitalization. The researchers compared the rate of premature childbirth among these women to the rate among women unaffected by bipolar disorder. They also looked at the size of the premature infants born to women with a history of the illness. The researchers concluded that women with a history of severe bipolar disorder have a significantly increased chance of giving birth to their children prematurely. They also concluded that the premature children of women with such a history are often unusually large for their gestational age. In addition, the researchers concluded that women previously affected by a severe bipolar illness have increased chances of giving birth to children with birth defects, as well as increased chances of experiencing stillbirth (death of a child in the womb after 20 weeks of pregnancy). Overall, the study\u2019s authors concluded that pregnant women with a history of hospitalization for bipolar illness have increased risks for premature childbirth that roughly equal the risks associated with a past history of hospitalization for major depression. They believe that doctors must pay special attention to pregnant women previously affected by any type of severe mood disorder. They also believe that elimination of other known risks for premature childbirth may lower the susceptibility of pregnant women with a history of one of these conditions.