Impact of 'LH activity' supplementation on serum progesterone levels during controlled ovarian stimulation: a systematic review

BACKGROUND: The influence of LH on serum progesterone rise during gonadotrophin stimulation is a matter of debate. The purpose of this analysis was to assess the impact of supplementation with 'LH activity' products on serum progesterone changes before hCG administration in GnRH analog-treated women. METHODS: A computerized literature search was performed to identify studies comparing FSH treatment alone to those that provided supplementation with 'LH activity' using hMG, recombinant (r)LH (rLH) or hCG in GnRH analog protocols. Data regarding stimulation regimens were extracted from those that reported serum progesterone levels at the time of hCG in order to assess the specific role of LH activity products. RESULTS: Serum progesterone determination at the time of hCG administration was performed in 34 out of 108 studies comparing the effects of FSH alone or in combination with LH activity products. In a vast majority, no significant difference in serum progesterone could be found between stimulation regimens. However, in four studies where LH activity (three hMG and one rLH) was administered from the beginning of ovarian stimulation, serum P-values were significantly decreased. In contrast, in two studies where LH activity (hCG) was provided during the late follicular phase, serum P-values were significantly increased. Analysis of confounding factors showed that the intensity of ovarian stimulation is the most important determining factor to explain serum progesterone elevation at the time of hCG administration, CONCLUSIONS: This systematic review shows that providing LH activity supplementation in combination with FSH during ovarian stimulation does not have a consistent effect on serum progesterone concentrations at the time of hCG administration. However, these data also suggest that, in accordance with physiological concept, the timing of LH activity administration could influence the impact on serum progesterone changes.