How Much Time to Conceive?

This morning my wife presented me with a rather interesting statistic: a healthy couple has a 25% chance of conception every month [1], and that this should result in a 75% to 85% chance of conception after a year. This sounded rather interesting and it occurred to me that it really can’t be that simple. There are surely a lot of variables which influence this probability. Certainly age should be a factor and, after a short search, I found some more age-specific information which indicated that for a woman in her thirties, the probability is only around 15% [2,3].

I suspect that one of the most important questions that people ask when they make the decision to have a child is: how long is it going to take us to get pregnant? The probabilities mentioned above should provide an answer to this question. But these probabilities are estimates at best (albeit, no doubt, educated estimates!) and are associated with some not insignificant uncertainties. So, how important is the value of the monthly probability in determining the time to conception? […]