Cumulative pregnancy probabilities among couples with subfertility: effects of varying treatments

To model the cumulative probability of pregnancy among couples with subfertility without a definitive diagnosis, according to different treatment strategies.

A beta distribution of fecundity was fitted that reproduced the cumulative probability of pregnancy in prospective studies of natural fertility, and this distribution was applied to simulated cohorts starting with one million couples each. Probabilities of pregnancy were generated for each cycle of each couple.

Simulation study. PATIENT(S): Hypothetic subfertile population. INTERVENTION(S): After 2 or 4 years of attempting pregnancy and diagnostic evaluation to exclude anovulation, tubal obstruction, and severe male factor, simulated treatments were applied to the remaining nonpregnant couples, with treatment effects based on published literature. MAIN OUTCOME MEASURE(S): Simulated cumulative probability of pregnancy. RESULT(S): Initially, the cumulative probability of pregnancy was highest for early treatment with IVF, but over time, conservative treatment or frequent intercourse approached the same cumulative probability. CONCLUSION(S): In couples without clear indications for IVF, the main benefit of early IVF may be to shorten time to pregnancy, a benefit that must be weighed against costs and potential adverse outcomes. Couples should be encouraged to maintain regular intercourse to maximize chances of pregnancy, even after unsuccessful treatment attempts.