The Non-linear Association Between Serum Level of Anti-Mullerian Hormone and in vitro Fertilisation Outcome

Aim of the study was to analyse the relationship between Anti-Mullerian Hormone (AMH) serum level and in vitro fertilisation (IVF) with and without intra-cytoplasmic sperm injection (ICSI) outcome. We performed a retrospective study which included 1073 patients (mean age 34.68 +/- 4.28 years, mean body mass index 22.7 +/- 15.65 kg/m(2)) who performed IVF or IVF/ICSI between January 2013 and December 2016. We found that AMH serum level was age-independent positively related with oocytes (beta=0.329, p< 0.0001) and zygotes number (beta=0.248, p< 0.0001) and negatively correlated with fertilization rate (beta=-0.108, p=0.001). In multivariate regression, after adjustment for confounders, only oocytes number, but not AMH serum level, was associated with zygotes number (beta=0.814, p< 0.0001) and fertilisation rate (beta=0.133, p=0.001). Patients with AMH in the range 1.1-5 ng/mL had significantly higher biochemical (65.3% versus 56.6%, p=0.009) and clinical pregnancy rates (57.7% versus 49.2%, p=0.014) in comparison with patients with AMH below 1.1 ng/mL and higher clinical pregnancy rates in comparison with patients with AMH above 7 ng/mL (57.7% versus 44%, p=0.011). Logistic regression analysis showed that AMH was positively associated with biochemical (OR 1.19, p=0.003) and clinical pregnancy (OR 1.16, p=0.009) independently of age and number of good embryos transferred in patients with AMH below 5 ng/mL. In turn, when only patients with normal ovarian reserve were analysed (AMH above 1.1 ng/mL), we found an age-independent negative association between AMH and clinical pregnancy (OR 0.93, p=0.014). AMH serum level is associated with both quantitative response (oocytes number) and qualitative parameters (pregnancy rate) during IVF/ICSI. We also found a bimodal relationship between AMH and pregnancy rates, which were positively associated in patients with AMH below 5 ng/mL, although higher AMH values seem to have a negative impact on pregnancy chances.