Spontaneous live birth after in vitro fertilisation treatment: frequency and associated factors

International audienceINTRODUCTION. Spontaneous live births (SLB) after in vitro fertilisation (IVF) treatment are not unusual, but reported SLB rates vary widely and little is known of their associated factors. Our objective was to examine the frequency of SLB and their associated factors among couples who had had IVF, successfully or unsuccessfully.METHODS. A retrospective cohort of couples was recruited in eight French IVF centers. The couples had begun IVF treatment in the participating centers between 2000 and 2002, and were followed-up by postal questionnaire between 2008 and 2010. Analysis was carried out on 2134 couples who were still together at the time of the postal survey. Separate analyses were conducted according to theoutcome of medical treatment: live birth (n¼1320) or no (n¼814). Multivariate analysis that included socio-demographic and medicalcharacteristics was conducted using logistic regression.RESULTS. The SLB rate was 17% among couples who had had a first live birth through medical treatment and 24% among couples whohad unsuccessful treatment. In both groups, SLB was associated with younger age of the women, fewer IVF attempts and the originof infertility. In couples who had not been successful with IVF, SLB was also associated with a shorter duration of infertility.CONCLUSION. Even in a population which had had IVF because of a very low monthly probability of conception, SLB is still possible,especially among couples who did not succeed in having a child through fertility treatment. Occurrence of SLB was mainly related to a better initial fertility prognosis