A comparison of Doppler measures of ovarian blood flow between women with and without ovarian dysfunction and correlations of Doppler indices with ovarian dysfunction markers: a meta-analysis

BACKGROUND: Doppler ultrasonography is used to study ovarian vascular characteristics. However, the outcomes are reported with a considerable variability in literature. Here we review the differences in Doppler ultrasound-measured ovarian blood flow indices between women with and without ovarian dysfunction and seeks correlations between Doppler measures and ovarian markers. METHODS: A literature search was conducted in electronic databases (Google Scholar, Ovid, PubMed, Science Direct, and Springer) to identify studies that used Doppler for ovarian blood flow examination and reported Doppler measures in women with and without ovarian dysfunction and/or the correlations between wDoppler indices and markers of ovarian dysfunction. After quality assessment of included studies, a meta-analysis of weighted mean differences (WMDs) between women with and without ovarian dysfunction in vascularization index (VI), flow index (FI), vascularization flow index (VFI), pulsatility index (PI) and resistance index (RI) was performed. Correlation coefficients between Doppler indices and markers of ovarian dysfunction were pooled to achieve overall estimates. RESULTS: A total of 27 studies [2,377 women with ovarian dysfunction and 308 controls; age 27.7 years, 95% confidence interval (CI): 26.4 to 29.1] were included. These studies were of moderate quality. The VI (WMD 9.75; P<0.0001), FI (WMD 2.73; P<0.0001), and VFI (WMD 1.29; P<0.0001) were significantly higher whereas PI (WMD −1.08; P=0.001) and RI (WMD −0.26; P<0.0001) were significantly lower in women with polycystic ovarian syndrome (PCOS) than in normal women. In women undergoing in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI), antral follicle count was positively correlated with VI (r=0.24; P=0.001), FI (r=0.42; P<0.0001), and VFI (r=0.25; P=0.002). In women with PCOS, testosterone had statistically non-significant correlations with VI (r=0.40; P=0.081), and VFI (r=0.39; P=0.063) and was inversely correlated with PI (r=−0.30; P<0.0001) and RI (r=−0.48; P<0.0001). In women with PCOS, luteinizing hormone (LH) was inversely correlated with PI (r=−0.26; P=0.086) and RI (r=−0.25; P=0.007). CONCLUSIONS: Doppler indices are found significantly different in women with and without ovarian dysfunction and have significant correlations with markers of ovarian dysfunction. These results support the use of Doppler ultrasound to examine ovarian dysfunction. High statistical heterogeneity observed herein should be studies in future investigations.