Early follicular progesterone concentrations and in vitro fertilization pregnancy outcomes

In IVF cycles using a GnRH agonist down-regulation short protocol, when the concentration of P on day 4 of stimulation was >3 ng/mL, patients experienced a significantly reduced implantation rate (14.1%), pregnancy rate (24.6%), and ongoing pregnancy rate (20.0%), with an elevated early miscarriage rate (18.8%).