Asian ethnicity is an independent determinant of ovarian reserve and response in women undergoing fresh IVF-ET cycles

Abstract

Studies have shown that ethnicity can be an independent determinant of ovarian reserve and response in IVF-embryo transfer (ET) cycles. In this context, we investigate if ovarian reserve and response parameters differ among Asian and Caucasian women. Cross-sectional study. Women <37 years, with baseline follicle stimulating hormone (FSH) <12 mIU/mL, AMH >1 ng/mL and antral follicle count (AFC) >5 undergoing fresh IVF-ET for unexplained infertility during a 5-year period were assessed for inclusion. Women with poor ovarian reserve (defined as AMH<1, FSH >12, or AFC<5), PCOS, or a history of oophorectomy were excluded. Of those included, ovarian reserve and response parameters were compared between Asians and Caucasians. Ovarian reserve was assessed by day 3 FSH, AMH, and AFC. Ovarian response was determined by stimulation duration, total gonadotropins and number of oocytes retrieved, with the primary outcome being the number of mature oocytes retrieved. A multivariate regression model was constructed for the primary outcome to account for potential confounders. 1378 women were included, of which 390 (28.3%) and 988 (71.7%) were Asian and Caucasian, respectively. Asians were slightly older (33.7±2.7 vs. 33.3±2.9 years; P=0.02) with lower BMIs (22.1±4.3 vs. 22.9±5.5 kg/m2; P=0.01). Asians had lower AFCs than Caucasians (13.9±4.4 vs. 14.7±4.3; P=0.01). While still within normal range, Asians had higher day 3 FSH levels (5.5±2.8 vs. 4.8±2.8 mIU/mL; P<0.001). There was no difference in AMH levels between the groups. Despite a comparable stimulation duration and gonadotropin dosage, the total oocyte yield (13.6±6.2 vs. 14.8±7.0; P=0.003) and mature oocyte yield (10.1±6.1 vs. 12.0±5.6; P<0.001) was lower in Asians. Overall, the number of oocytes per unit of AMH was lower in Asians compared to Caucasians (4.3±3.4 vs. 5.3±3.4; P<0.001). Multivariate regression suggested that Asian women yield approximately 3 fewer mature oocytes than Caucasians (co-efficient +2.8; 95% CI 1.68-3.67; P=0.003; R2 0.63). Despite these differences, the live birth rate in Asians (42.6%) was comparable to Caucasians (48.6%). Despite similar ages, AMH levels, ovarian stimulation duration and gonadotropin doses, Asian women have decreased AFCs and a lower yield of total and mature oocytes compared to their Caucasian counterparts. These results suggest a decreased ovarian response in Asian women undergoing IVF-ET.Tabled 1Comparison of baseline demographics, ovarian reserve and ovarian response parameters (n=1378)ParameterAsian (n=390)Caucasian (n=988)PAge (years)33.7 (±2.7)33.3 (±2.9)0.02BMI (kg/m2)22.1 (±4.3)22.9 (±5.5)0.01Baseline FSH (mIU/mL)5.5 (±2.8)4.8 (±2.8)<0.001Baseline AMH (ng/mL)3.2 (±2.6)3.2 (±2.9)NSBaseline AFC13.9 (±4.4)14.7 (±4.3)0.002Total stimulation days9.3 (±1.7)9.5 (±1.8)NSTotal gonadotropins (IU)2460.9 (±1287.6)2358.1 (±1157.4)NSTotal oocytes retrieved13.6 (±6.2)14.8 (±7.0)0.003Mature oocytes retrieved10.1 (±6.1)12.0 (±5.6)<0.001% Mature oocytes74.9 (±27.2)82.0 (±15.8<0.001Mature oocyte retrieved: AMH4.3 (±3.4)5.3 (±3.4)<0.001 Open table in a new tab