Nine studies with a matched control group were included in the review (458 patients with PCOS undergoing 793 cycles and 694 matched control patients undergoing 1,116 cycles). Of these, one was a prospective matched study (84 patients with PCOS undergoing 104 cycles and 84 controls undergoing 116 cycles); the other studies were retrospective.
PCOS was associated with a significantly reduced chance of oocyte retrieval per started cycle (OR reported as 0.5 in the text, 95% CI: 0.2, 1.0; based on 4 studies, n=697), but there was no difference in the chance of embryo transfer per oocyte retrieved compared with patients without PCOS.
PCOS was associated with a significant increase in the number of oocytes per retrieval (random-effects WMD was reported as 3.4 in the text, 95% CI: 1.7, 5.1; based on 5 studies, n=1,020), but significant heterogeneity was found (p=0.005). There was no significant difference in the number of oocytes fertilised compared with patients without PCOS.
There was no significant difference in the clinical pregnancy rate (37.4% versus 32.3%; based on 8 studies, n=1,537).
The incidence of OHSS after oocyte retrieval was rarely clearly reported. One study reported a trend towards an increase in OHSS in patients with PCOS. One study reported that among patients with PCOS, 16.6% developed mild to moderate OHSS and 3.9% developed severe OHSS requiring hospitalisation. One study reported three cases of OHSS among patients with PCOS compared with one case among controls (sample size and reference were not reported so the relative proportions could not be calculated).
There were no significant differences between women with or without PCOS in the clinical pregnancy rate per started cycle, the number of live births per cycle started, the clinical pregnancy rate per oocyte retrieved, or the number of miscarriages.