Reproductive behaviour in modern western society has changed dramatically in the last two decades. Parenthood is now well planned. If planned pregnancies do not occur as expected, early infertility care is often demanded with the risk of over-treatment. Live birth rates in untreated subfertile couples reach nearly 55% in 36 months. During this period, self-monitoring with natural family planning (NFP) methods may be all that is necessary, especially in couples with unexplained infertility.