(HealthDay News) – A new mathematical model can help predict the chances that a couple will conceive based on how many months they have been trying to conceive.

Peter D. Sozou, PhD, and Geraldine M. Hartshorne, PhD, from the University of Warwick in Coventry, UK, developed a general numerical computational model to examine what can be concluded about a couple’s future chances of pregnancy based on the number of menstrual cycles over which they have been trying to conceive. They applied their methods to model the impact of female reproductive aging on the chances of conception.

The researchers found that the commonly-used standard of 12 cycles of non-conception as indicative of subfertility was fairly robust. Depending on the population from which a couple was drawn and the precise subfertility metric that was most relevant, a smaller or larger number of cycles may be more appropriate. Based on this model, for women >35 years, investigation and treatment of infertility may be started sooner than for younger women. Ignoring reproductive decline during the attempted conception period correlated with a two-cycle increase in the number of cycles before reaching a subfertility metric.

“The methods described in this study may be helpful for the further development of decision support systems in fertility assessment, with potential benefits to patients and clinicians, and to health service funders who must allocate resources through decisions that affect large numbers of patients,” the authors write.

Full Text (subscription or payment may be required)