Objective: To determine the incidence of spontaneous pregnancy in women who were not actively undergoing therapy after a successful attempt at IVF/intracytoplasmic sperm injection and to characterize its pattern of occurrence.
Design: Retrospective postal questionnaire.
Setting: An assisted reproduction unit at a university-based teaching hospital.
Patient(s): Five hundred thirteen replies were received from 530 questionnaires mailed.
Intervention(s): None.
Main outcome measure(s): Spontaneous pregnancy. Women who did and did not conceive spontaneously after successful IVF treatment were compared in terms of their age, duration of infertility, previous reproductive history, and indication for treatment at the time of assisted reproduction.
Result(s): The rate of spontaneous conception among the survey respondents was 20.7%. Younger women (</=34 years of age) had a higher rate of spontaneous conception, as did those with a shorter duration of infertility. Women with unexplained infertility and endometriosis also were more likely to conceive. Few of those who had undergone intracytoplasmic sperm injection conceived, whereas 21.6% of those whose partners had had sperm quality sufficient for IVF later conceived spontaneously.
Conclusion(s): The chances of spontaneous conception after successful ART therapy are significant in some groups of patients. This has implications for the practice of assisted reproduction and the obstetric care of patients who conceive with treatment. Contraceptive advice may need to be provided to couples who undergo IVF/intracytoplasmic sperm injection.