The poor responder in IVF: is the prognosis always poor? A systematic review

BACKGROUND: In IVF treatment a considerable proportion of women are faced with a low number of oocytes retrieved. These poor responders have reduced pregnancy rates compared with normal responders. However, this may not be applicable to all poor responders. This review aims at identifying patient characteristics and ovarian reserve tests (ORT) that will determine prognosis for pregnancy in poor responders. METHODS: A systematic search was conducted in PubMed, Embase, Cochrane and SCOPUS databases in April 2010. Studies regarding patient characteristics or ORT in poor responders and their pregnancy prospects were included. All included papers were summarized in descriptive tables. RESULTS: Nineteen studies were included. Pooled data of six studies comparing poor and normal responders demonstrated clearly lower pregnancy rates in poor responders (14.8 versus 34.5%). Ten studies indicated that older poor responders have a lower range of pregnancy rates compared with younger (1.5-12.7 versus 13.0-35%, respectively). Four studies showed that pregnancy prospects become reduced when fewer oocytes are retrieved (0-7% with 1 oocyte versus 11.5-18.6% with 4 oocytes). Five studies concerning pregnancy rates in subsequent cycles suggested a more favourable outcome in unexpected poor responders, and if >= 2 oocytes were retrieved. CONCLUSIONS: Poor responders are not a homogeneous group of women with regards to pregnancy prospects. Female age and number of oocytes retrieved in particular will modulate the chances for pregnancy in current and subsequent cycles. Applying these criteria will allow the identification of couples with a reasonable prognosis and balanced decision-making on the management of poor responders.