Older first time mothers more prone to develop mental illness

Swedish researchers have revealed that women who have their first baby after age 35 are more likely to develop a mental illness after the birth.

The researchers say older first time mothers have double the risk of suffering from postpartum psychosis, a mental illness involving episodes where the individual is unable to distinguish between reality and their imagination, which requires the use of anti-psychotic drugs.

The researchers at the Karolinska Institute in Stockholm carried out a study of risk factors associated with psychotic illness after childbirth and they say the risk of developing psychosis during the first 90 days after childbirth increases with age and could endanger the newborn child.

The Swedish study which was based on data gathered from all the nearly 750,000 first-time mothers who gave birth in Sweden between 1983 and 2000, shows that when women over 35 gave birth for the first time they were 2.4 times more likely to develop postpartum psychosis than those younger than 19.

The researchers say as many as 80% of new mothers experience some kind of mental disturbance or mild depression, most often these might involve short-lived cases of the "baby blues" in the days after birth, and mild to moderate postnatal depression in the weeks and months that follow, but only about one in 1,000 women suffer from actual psychosis in the first months after giving birth.

Postpartum psychosis is a serious mental disorder, involving delusions, hallucinations, severe eating or sleeping disturbances, suicidal tendencies and can be dangerous for mother and child as there is greater risk of self-harm and suicide and the safety of the newborn baby can be threatened.

The condition requires immediate medical attention including the administration of anti-psychotic drugs and hospitalisation and though the majority of women who suffer from such a psychosis have prior psychotic histories, the Karolinska researchers say almost 50% of the cases appeared in women "without prior psychotic hospitalisation."

The research also established that there was less risk of psychosis with higher infant birth weight and maternal diabetes and other factors, including smoking and not living with the infant's father, had no or limited impact on the risk of psychosis during the postpartum period.

The researchers say their finding highlights the importance of carefully monitoring women in the first month after delivery - exactly why the risk of psychosis is greatest then is unclear but they suggest the profound hormonal fluctuations they experience at this time renders some women more vulnerable.

The research is published by the Public Library of Science medical journal.