Date Time Study challenges recommended wait time between pregnancies New Curtin University-led research has called into question existing health advice that mothers wait a minimum of two years after giving birth to become pregnant again, in order to reduce the risk of adverse pregnancy outcomes, such as preterm and small-for-gestational age births. The research found that a World Health Organization (WHO) recommendation to wait at least 24 months to conceive after a previous birth may be unnecessarily long for mothers in high-income countries such as Australia, Finland, Norway and the United States. Lead researcher Dr Gizachew Tessema from the Curtin School of Population Health said because the WHO advice was based on limited evidence from resource-limited countries, it was necessary to investigate whether the 15-year-old recommendation was relevant for higher-income settings.