Spontaneous pregnancies among couples previously treated by in vitro fertilization

Objective: To determine the frequency of live births following spontaneous pregnancy (BSP) and to examine their associated factors among couples who have unsuccessfully or successfully experienced fertility treatments.

Design: Retrospective cohort.

Setting: Eight IVF centers.

Patient(s): A total of 2,134 couples who began IVF treatment in the centers in 2000-2002 and were followed up by a postal questionnaire sent 7-9 years after they started treatment in the inclusion center.

Intervention(s): None.

Main outcome measure(s): Rates of BSP and factors associated with BSP. Univariate and multivariate analyses were conducted using logistic regression.

Result(s): The BSP rate was 17% (218/1,320) among couples who had previously had a child through medical treatment and 24% (193/814) among couples who had remained childless after treatment. In both groups, the probability of BSP was higher among younger women and increased with a smaller number of IVF attempts. Probability was also higher when the cause of infertility was unexplained.

Conclusion(s): Our results should give hope to couples who have been unsuccessfully treated by IVF, especially young couples with unexplained infertility. Nonetheless, it should be remembered that the BSP rates are cumulative rates observed over a long period of time and that these couples have a very low monthly probability of conceiving.