Comparison of intravaginal progesterone gel and intramuscular 17-α-hydroxyprogesterone caproate in luteal phase support

The main objective of this study was to compare the pregnancy rates of intramuscular (IM) 17-α-hydroxyprogesterone caproate (17-HPC) and intravaginal (IV) progesterone gel administration in in vitro fertilization-embryo transfer (IVF-ET) cycles. The IM 17-HPC and IV progesterone groups included 632 (66.4%) and 320 (33.6%) women undergoing the first cycles of IVF-ET treatment, respectively. Multivariate analyses annotated for all potential confounders showed that the use of IV progesterone retained a predictive value for the total β-human chorionic gonadotropin (hCG) positivity and clinical pregnancy rates [adjusted odds ratio (OR), 1.97; 95% confidence interval (CI), 1.28–3.03; P=0.002; and OR, 1.66; 95% CI, 1.07–2.60; P=0.03, respectively]. However, biochemical and on-going pregnancy rates did not differ significantly between the groups (OR, 1.85; 95% CI, 1.00–3.41; P=0.05; and OR, 1.43, 95% CI, 0.89–2.30; P=0.14, respectively). Luteal phase support (LPS) with IV progesterone gel in comparison with IM 17-HPC appears to be associated with higher clinical pregnancy rates in IVF-ET cycles. However, this benefit is clinically irrelevant in terms of on-going pregnancy outcomes.