Compared with women who had given birth 11 to 12 months earlier, first-time mothers were found to have seven times the risk of psychiatric-related hospital admissions during the first 10 to 19 days of their baby's life.
The increase in risk remained throughout the first three months after childbirth, regardless of the age of the mother. Postpartum risk appeared to decrease with subsequent pregnancies, researcher Trine Munk-Olsen, MSc, tells WebMD.
Munk-Olsen and colleagues analyzed the medical histories of close to 2.4 million Danish citizens registered in a national health database.
Their findings are published in the Dec. 6 issue of The Journal of the American Medical Association.
"This study confirms that the timing of postpartum risk is very precise," she says. "The first month after giving birth is definitely the most dangerous time for postpartum mental disorders, but the risk remains for several months after."
Dads Weren't Depressed
Between 1973 and 2005, just over 630,000 women and 547,000 men in Denmark became parents for the first time. During the same period a total of 1,171 women ad 658 men were admitted to psychiatric hospitals during their first year of parenthood.
Several smaller studies have suggested that postpartum depression occurs among new dads, as well as new moms. But the Danish findings do not support this.
Within the first three month after becoming parents, roughly 1 in 1,000 women and 1 in 3,000 men in the Danish population studied experienced severe mental disorders that required hospitalization or outpatient psychiatric treatment.
"Unlike motherhood, fatherhood was not associated with any increased risk of hospital admission or outpatient [psychiatric] contact," the researchers note.
Routine Screening Needed
As many as one in seven new mothers in the U.S. experience some degree of postpartum depression, according to government figures.
Though earlier studies also suggested that first-time moms have the highest risk for mental health problems, the Danish population study is by far the largest to examine the issue and the first large-scale postpartum depression trial to be conducted in two decades.
The findings should serve as a wake-up call to public health officials in the U.S. who have largely ignored postpartum depression in the past, says a University of Pittsburgh postpartum researcher who co-wrote an editorial accompanying the study.
"Knowing what we do about the risks of postpartum depression, we must recognize our responsibility to address this illness through improved research and greater access to care and services," Katherine L. Wisner, MD, MS, says in a news release from the University of Pittsburgh.
Wisner and colleagues Dorothy K.Y. Sit, MD, and Christina Chambers PhD, MPH, called for the implementation of universal postpartum mental health screening, to be conducted between two and 12 weeks after childbirth.
They also called for the rapid treatment of women with postpartum depression, which can benefit the new mom, her baby, and the entire family.
"Any form of screening program has to be combined with effective treatments," Sit tells WebMD. "Physicians, providers, and patients need to be informed about the different treatment options and the importance of providing treatment quickly."
Mothers-to-be should be made aware of the risks and the symptoms of postpartum depression, Sit says. Some symptoms -- such as poor concentration, extreme tiredness, sleep disturbances, and changes in appetite -- are common among new parents, even if they aren't depressed.
But other symptoms -- such as persistent anxiety or irrational fears, recurrent thoughts of dying or preoccupation with death, and thoughts of harming yourself or your baby -- should never be ignored.
"Maternal depression exacts a heavy toll on women and the health and well-being of their children," Sits and colleagues wrote.