Altered kinetics of pituitary response to gonadotropin-releasing hormone in women with variant luteinizing hormone: correlation with ovulatory disorders

A common polymorphic allele of the LH beta-subunit gene is associated with higher exogenous FSH consumption during controlled ovarian stimulation for assisted reproductive technology

BACKGROUND

V-betaLH is a common genetic variant of LH caused by two polymorphic base changes in the beta subunit gene, altering the amino acid sequence (Trp8Arg and Ile15Thr). In a previous-preliminary trial performed in women undergoing IVF, it was demonstrated that carriers of v-betaLH show sub-optimal ovarian response to a standard long GnRH-agonist down -regulation protocol when stimulated with pure recombinant FSH (r-hFSH). The aim of this study was to confirm the hypothesis that women with v-betaLH display hypo-sensitivity to exogenous FSH in a larger IVF population and to explore the frequency of this variant in a Danish female population.

METHODS

In the present study, the effect of v-betaLH was retrospectively investigated in a larger series of women undergoing controlled ovarian stimulation (COS) and, for the first time, in a Danish IVF population. A total of 220 normogonadotrophic women following a long GnRH-agonist down-regulation protocol received an individualized dose of r-hFSH (100 IU and 375 IU s.c. daily) according to antral follicle count, baseline FSH, body mass index and age. The LH genotype was assessed in all patients by immunofluorometric assay.

RESULTS

V-betaLH was present in 11% of patients, whereas the allelic frequency was 12%. The study population was divided into two groups according to their LH genotype. Group A consisted of 196 wt/wt women. Group B included 24 individuals with v-betaLH (21 heterozygous and 3 homozygous). No statistically significant differences in the mean number of oocytes retrieved, fertilization rate and pregnancy rate per cycle were observed between groups. However, Group B received a significantly higher cumulative-dose of r-hFSH than Group A (2435.86 +/- 932.8 IU versus 1959.8 +/- 736.45 p = 0.048). When one-way ANOVA in a within design was applied, the LH genotype had a statistically significant effect (p < 0.01) on the cumulative dose of r-hFSH, showing a progressive increase from wt/wt (1959.8 +/- 736.45 IU) to v-betaLH hetero- (2267.5 +/- 824.3) and homozygotic women (3558.3 +/- 970.9).

CONCLUSIONS

These results confirm that carriers exhibit hypo-sensitivity to exogenous FSH during COS, documenting that the frequency of v-betaLH in Denmark is similar to a number of European countries.

Recombinant human LH supplementation versus supplementation with urinary hCG-based LH activity during controlled ovarian stimulation in the long GnRH-agonist protocol: a matched case-control study

An observational, matched, case-control study was carried out to compare the efficacy of recombinant human luteinizing hormone (r-hLH) supplementation with that of urinary human menopausal gonadotrophin (u-hMG)-based LH activity during controlled ovarian stimulation (COS) for assisted reproductive technology (ART) using a long gonadotrophin-releasing hormone (GnRH)-agonist protocol. A total of 4719 women, 1573 per group, matched by age, body mass index, indication and number of previous ART cycles, were treated with either recombinant human follicle-stimulating hormone (r-hFSH) and r-hLH in a fixed 2:1 ratio or u-hMG, either alone or in combination with r-hFSH, after down-regulation in a long GnRH-agonist protocol. Compared with the two u-hMG groups (u-hMG alone or in combination with r-hFSH, respectively), r-hFSH consumption was significantly lower (p < 0.001; p < 0.001), and pregnancy rates per cycle (p = 0.006; p = 0.022) and per embryo transfer (p = 0.025; p = 0.008), and implantation rate per embryo transferred (p < 0.001; p < 0.001) were significantly higher in the group treated with the fixed combination of r-hFSH and r-hLH. In COS protocols with r-hFSH, supplementation with r-hLH appears to be more effective than supplementation with u-hMG using the long GnRH-agonist protocol for ART.

Suboptimal response to GnRHa long protocol is associated with a common LH polymorphism

The aim of this observational preliminary trial was to estimate the association between the most common polymorphism of LH (LH-β variant: v-βLH), with different profiles of ovarian response to recombinant human FSH (rhFSH). A total of 60 normogonadotrophic patients undergoing a gonadotrophin-releasing hormone analogue long down-regulation protocol followed by stimulation with recombinant human FSH (rhFSH) for IVF/intracytoplasmic sperm injection, and in whom at least five oocytes were retrieved were retrospectively included. On the basis of the total rhFSH consumption, patients were divided into three groups: Group A: 22 women requiring a cumulative dose of rhFSH >3500 IU; Group B: 15 patients requiring 2000-3500 IU; Group C (control): 23 women requiring <2000 IU. The presence of v-βLH was evaluated using specific immunoassays. Peak oestradiol concentrations were significantly lower in Group A when compared with both groups B (P < 0.05) and C (P < 0.001). Group A had a significantly lower (P < 0.05) number of oocytes retrieved (7.3 ± 1.5, 11.7 ± 2.4 and 14.7 ± 4.1 in the three groups, respectively). Seven carriers (31.8%) of v-βLH were found in Group A, whereas only one variant (6.7%) was observed in Group B; no variant was detected in Group C. These preliminary results suggest that v-βLH is more frequent in women with ovarian resistance to rhFSH.