We have become aware of a number of pregnancies which have occurred in women with chronic psychotic illnesses whose medication has been changed from traditional oral or depot antipsychotics to atypical drugs. This can be explained by the loss of the contraceptive side-effects produced by drug-induced hyperprolactinaemia in these women. Most atypical antipsychotic drugs (e.g. olanzapine, quetiapine, clozapine) have a negligible effect on prolactin levels, whereas older drugs such as chlorpromazine and haloperidol, as well as sulpiride, amisulpride and risperidone, can cause significant hyperprolactinaemia in some women. Although these should not be considered as contraceptives, there is undeniably a contraceptive effect.

We have documented four patients in our local services who have recently had unplanned pregnancies in association with this change in medication. All four women had their medication changed from older, typical antipsychotics in an effort to improve their symptoms and reduce side-effects. Three were known to have a partner at this time. Two were also known to have hyperprolactinaemia, presumably as a result of taking typical antipsychotics. All four women had an unplanned pregnancy following the change in medication and all but one then had their atypical antipsychotic medication stopped. All four of these women decided to proceed with their pregnancies. Two women became acutely ill during their pregnancies and were admitted to psychiatric hospital. All four were admitted postnatally to a mother and baby psychiatric unit, three with acute psychotic symptoms and one with less severe symptoms but with concerns about her ability to parent her child. All four women required very high levels of input from mental health and social services; despite this, only one has been able to continue to provide care for her child.

Unwanted and unplanned pregnancies are clearly undesirable and a doctor could be deemed negligent if a pregnancy results from prescribing without appropriate advice on risk and contraception, for example, in the case of antibiotics given to women on the pill. Unwanted pregnancies are of particular concern in women with chronic psychotic illnesses. Not only does the mother have a substantially increased risk of acute relapse following childbirth, but there is also clear evidence that children of parents with mental illness suffer greater social disadvantage, increased psychological and psychiatric disturbance and higher rates of emotional, sexual and physical abuse (Reference Gregoire and GregoireGregoire, 2000).

There is relatively little information available on the sexuality, contraceptive habits, fertility or beliefs and wishes about reproduction in people with severe mental health problems. It has been suggested that fertility among people with severe mental illness is similar to that of the general population (Reference Lane, Mulvany and KinsellaLane et al, 1992) and there can be little doubt among clinicians that the changing patterns of care from hospital to living in the community are likely to have altered behaviour and expectations of sexuality and reproduction. Advice to people with severe mental illness about contraception is likely to be poor and they are more likely to have unplanned and unwanted pregnancies (Reference Miller and FinnertyMiller & Finnerty, 1996). Sexuality is an area of patients' lives that psychiatrists tend to neglect even though they and their patients acknowledge its importance (Reference Pinderhughes, Barrabee and RaynaPinderhughes et al, 1972).

The cases we have been involved with illustrate what we believe to be an increased risk of pregnancy in women changing from conventional to atypical antipsychotics. The potential risks to mother and child associated with such pregnancies are clear and the lack of attention generally paid to sexuality and contraception by those caring for people with mental illnesses must therefore be a cause for concern. On the basis of current knowledge, we should assume that our patients are sexually active and need advice and assistance with contraception. We recommend that the potential effect on fertility be discussed with all patients changing from a traditional to an atypical antipsychotic and that mental health professionals be active in promoting effective contraception.