The terms "planned", "unplanned", "intended", "unintended", "wanted" and "unwanted" are often used in relation to pregnancy in health policy, health services and health research. This paper describes the findings relating to women's understanding of these terms from the qualitative stage of a British study. We found that when discussing the circumstances of their pregnancies, women tended not to use the above terms spontaneously. When asked to explain the terms, women were able to do so but there was considerable variation in understanding. Most, but not all, were able to apply the terms. Women applied the term "planned" only if they had met four key criteria. Intending to become pregnant and stopping contraception were not sufficient criteria, in themselves, to apply the term; partner agreement and reaching the right time in terms of lifestyle/life stage were also necessary. In contrast, "unplanned" was a widely applied term and covered a variety of circumstances of pregnancy. The other terms were less favoured, "unwanted" being positively disliked. We recommend that survey questions eliciting information on women's circumstances of pregnancy do not rely on the above terms in isolation and, further, that a more circumspect use of the terms in policy and clinical settings is required.