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14-06-2010 | Mental health | Article

Schizophrenia shows lowest fertility rate among psychiatric population


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MedWire News: Patients with schizophrenia have a significantly lower level of fertility than those with other psychiatric disorders and mentally healthy controls, show study results.

However, fertility did increase with time since onset of illness in all psychiatric disorders, note researchers Thomas Laursen and Trine Munk-Olsen (Aarhus University, Denmark) in the journal Schizophrenia Research.

Several studies have addressed fertility rates in schizophrenia and other psychiatric populations. However, the researchers argue many of these are flawed since they do not take into account parental status at the time of onset of the disorder, time since onset of the disorder, and the possible effect of termination of pregnancy (TOP).

To address this, the researchers used Danish census data from 1950 onwards and linked this information to the Danish Psychiatric Central Register and Danish National Hospital Register to obtain information about induced TOP.

Compared with the general population, the lowest first-child fertility rate was found among men with schizophrenia with an incidence rate ratio (IRR) of 0.10 followed by women with schizophrenia (IRR=0.18).

By comparison, bipolar male patients had an IRR of 0.32 and female patients an IRR of 0.36, while male unipolar patients had an IRR of 0.46 and female patients an IRR of 0.57. In the group with other psychiatric disorders men had an IRR of 0.51 and women an IRR of 0.70.

However, fertility was modified by the number of previous children: both men and women with schizophrenia who had a least two children had the same incidence rate of having the next child as those with bipolar disorder, and almost the same rate as the general population.

Also time since onset of a psychiatric disorder influenced fertility rates - for example, women with schizophrenia had an IRR of 0.07 in the 9 months after diagnosis rising to 0.27 between 37 and 48 months after diagnosis.

“It seems very likely that symptoms are most severe at the time of the first episode entailing admission, and that they then gradually become less severe, thereby “allowing” the persons to consider having a child,” the authors comment.

Although women with a psychiatric disorder had higher rates of TOP in the current study than the comparison group, their IRR of first reproductive event (first birth or TOP, if any) was only slightly higher than their IRR of first birth.

“To our knowledge, it is the first study to fully describe reproductive patterns (up to four children) in patients with psychiatric disorders,” Laursen and Munk-Olsen comment.

MedWire ( is an independent clinical news service provided by Current Medicine Group, a trading division of Springer Healthcare Limited. © Springer Healthcare Ltd; 2010

By Andrew Czyzewski

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