New moms are in the greatest danger of developing psychotic illness in the first month after they give birth, a new study in hundreds of thousands of women shows.
This was true both for women who had been hospitalised for psychiatric illness in the past and for those who had not, Dr Christina Hultman of the Karolinska Institutet in Stockholm and her colleagues found.
Only about 1 in 1 000 women will develop postpartum psychosis, but the consequences can be grave for both mother and child, the researchers point out. Mothers who lose touch with reality may harm themselves or their infant, and also run the risk of future episodes of psychosis.
"Most women have only one episode and a short period of confusion and psychotic symptoms, but about 20% to 30% will have similar symptoms in their second pregnancy," Hultman said.
How the study was done
To investigate when postpartum psychosis risk is greatest, and also look for factors that could help identify at-risk women, Hultman and her team examined population registers for 745 596 Swedish women who gave birth for the first time between 1983 and 2000.
There were 892 women, or 1.2 per 1 000 births, hospitalised for psychosis within 90 days of delivery, the researchers found. Nearly one-third of the women were hospitalised within a week of having their child, while 59% were hospitalized within two weeks of delivery.
Almost half had never been hospitalised for psychiatric problems before. For these women, the risk of being hospitalized for a psychotic episode within the first month after giving birth was 10 times greater than it was after their baby was three months old.
These women were also at increased risk if they were 35 or older; having a high birth weight baby or having diabetes seemed to be protective. This may be because women with diabetes are more closely monitored while pregnant, Hultman and her team suggest.
Pregnancy may be trigger
It's still not clear, they say, why postpartum psychosis occurs, although there's evidence that the huge drop-off in estrogen levels that occurs after delivery could be a factor. "The most plausible explanation is that the pregnancy biologically and maybe also psychologically triggers a psychotic episode," Hultman said.
There are no "clear warning signs" during pregnancy a woman will develop postpartum psychosis, she added, although risk may be greater for a woman who suffers trauma or other complications during delivery, as well as for women who have low birth weight babies. Not surprisingly, risk also seems to be higher for women whose babies die soon after birth.
"A supportive network and good contact with your doctor during pregnancy is always important for the expecting woman," Hultman said. "It is good for all women to know more about the condition and that it could happen even if it is rare. I would also recommend discussing the issue of psychological reactions post-partum with your obstetrician if you are worried.
"Post-partum depression is fairly common and you are more vulnerable when giving birth due to all your emotions and feelings." – (Reuters health, February 2009)