Risk of rapid repeat pregnancy in women with schizophrenia

September 4, 2019

A recent population-based cohort study examined whether women with schizophrenia are at higher risk for rapid repeat pregnancy than their peers without schizophrenia.

A population-based cohort study conducted in Ontario, Canada, has found that women with schizophrenia are at significantly higher risk for rapid repeat pregnancy than their peers without schizophrenia. However, the study in the journal Schizophrenia Research also concluded that the two groups use non-barrier contraception at similar rates.

Data were gleaned from multiple sources, including Toronto-based Institute for Clinical Evaluative Services (ICES), Ontario’s Registered Persons Database (RPDB) and the Ontario Health Insurance Plan (OHIP).

The authors stated that women with schizophrenia are vulnerable to adverse reproductive health outcomes, noting that short interpregnancy interval, or rapid repeat pregnancy, is linked to maternal and infant complications that may be preventable. The study defined rapid repeat pregnancy as pregnancy within 12 months of an index live birth. The cohort consisted of all Ontario women between ages 18 and 49 who had a live birth between April 1, 2001, and March 31, 2013.

Among the 1,565 women with schizophrenia, 6.3% had a rapid repeat pregnancy, compared to 3.9% of the 924,657 women without schizophrenia, for an adjusted relative risk (aRR) of 1.31 and a 95% confidence interval (CI) of 1.07 to 1.59. The schizophrenia group also had more rapid repeat pregnancies resulting in live births (aRR 1.85; 95% CI: 1.26 to 2.72). But there was no difference in either pregnancy losses (aRR 1.50; 95% CI: 0.99 to 2.29) or induced abortions (aRR 1.07; 95% CI: 0.81 to 1.42) between the two groups.

In addition, the risk of rapid repeat pregnancy among primiparous women was greater for women with schizophrenia than those without: 6.1% vs. 3.9% (aRR 1.28; 95% CI: 1.01 to 1.62). In both groups, more than one in five women had a repeat pregnancy within 24 months of the index birth.

Post-delivery, non-barrier contraception (hormonal or surgical) use was comparable between the two groups: 43.7% for schizophrenia vs. 43.6% without schizophrenia (aRR 1.06; 95% CI: 0.93 to 1.20). Furthermore, women with schizophrenia were more likely to use injectable contraception: 14.1% vs. 10.1% (aRR 1.67; 95% CI: 1.35 to 2.07).

In primiparous women, use of hormonal or surgical contraception did not differ between those with and without schizophrenia.

Study findings might be attributed to the fact that women with schizophrenia are at high risk for unplanned pregnancy, due to being socially vulnerable, at increased risk for sexual assault, and having high rates of comorbid substance use disorders. In the current study, fewer than half the women with schizophrenia received any form of hormonal or surgical contraception in the first year after delivery.

Pregnancy complications may also be greater among women with schizophrenia, considering their baseline risk for medical comorbidities; increased rates of smoking, alcohol and substance dependence; and intimate partner violence.

“The postnatal period is an opportune time to initiate targeted interventions designed to optimize planning for any future pregnancies, and contribute to improving maternal and child health in this vulnerable group,” the authors wrote.

The investigators advocate educating women with schizophrenia about the risks of rapid repeat pregnancy as part of their post-delivery reproductive care.