Lack of association between endogenous LH and pregnancy in GnRH antagonist protocols

After the introduction of recombinant FSH preparations for IVF or intracytoplasmic sperm injection (ICSI), it became clear that good pregnancy rates could be achieved with or without any exogenous LH, irrespective of the protocol used. Both recombinant LH- and human chorionic gonadotrophin (HCG)-containing menotrophins are available, so biology and pharmacology could be nicely linked, if the following concept could be documented: subgroups of patients have low circulating LH concentrations, and thus low pregnancy rates, and when such patients were co-treated with recombinant LH, the pregnancy rates would increase. Indeed the two papers commented on clearly show that circulating LH concentrations are not associated with pregnancy rates and the concept of a beneficial effect of adding recombinant LH to subgroups of patients remains to be shown.