Evers JL. Female subfertility. Lancet 2002;360:151–9.
With an average monthly fecundity rate of only 20%, human beings are not fertile mammals. 10-15% of couples have difficulties conceiving, or conceiving the number of children they want, and seek specialist fertility care at least once during their reproductive lifetime. Dependent on the two main factors that determine subfertility, duration of childlessness and age of the woman, three questions need to be addressed before treatment is offered. Is it time to start the routine fertility investigation?--ie, has sufficient exposure to the chance of conception taken place? Are cost-effective, safe, and reliable treatments available for the disorder diagnosed? And, should the couple be referred straightaway for assisted reproduction?