Effect of baseline prolactin levels on the pregnancy outcomes after fresh embryo transfer

There is clinical disagreement on whether to treat hyperprolactinemia with medication before embryo transfer. The aim of this study is to identify the impact of basal prolactin (PRL) levels on pregnancy outcomes in fresh embryo transfer cycles.

This retrospective study involved 2,648 women who underwent basal PRL level testing and fresh embryo transfer between January 2015 and December 2020 at our Hospital's Department of Assisted Reproduction. Basal PRL levels can be classified into three categories: <30 (n = 2339), 30‑60 (n = 255), and ≥60 (n = 54) µg/l. Pregnancy outcome was defined as the primary outcome measure, and the live birth rate was defined as the second outcome measure. Subsequently, univariate and multivariable logistic regression analysis was used to reveal the association between basal PRL levels and pregnancy outcomes after considering several potential confounding factors.

Elevated basal PRL levels were found not a risk factor for pregnancy outcomes in patients receiving good-quality embryo transfer (p > .05). For pregnancy or not, female age (OR: 1.03; 95% CI: 1.01-1.05), embryos transferred (OR: 0.52; 95% CI: 0.41-0.65), and normal fertilization rate (OR: 0.68; 95% CI: 0.48-0.97) were found to be an independent risk factor. For ongoing pregnancy or not, female age (OR: 1.07; 95% CI: 1.03-1.11), embryos transferred (OR: 0.57; 95% CI: 0.37-0.88), and menstrual cycle (OR: 1.76; 95% CI: 1.22-2.54) were also independent risk factors.

There is no adverse impact on pregnancy outcomes during embryo transfer cycles with good-quality embryos when PRL levels are elevated.