Is chromosome analysis mandatory in the initial investigation of normovulatory women seeking infertility treatment?

BACKGROUND

There is no agreement about the frequency of chromosomal abnormalities (CAs) in the female partner of an infertile couple and therefore there is no evidence base for determining whether karyotype analysis is mandatory before the initiation of infertility treatment. The aim of this prospective study was to estimate the prevalence of karyotype abnormalities in normovulatory women attending an infertility clinic and compare it to that known to be present in the newborn female population.

METHODS

Cytogenetic testing was performed in 1206 women with normal ovulatory cycle seeking infertility treatment. At least 15 GTG-banded metaphases were analysed in each case. In the case of a structural abnormality, fluorescent in situ hybridization (FISH) analysis and high resolution banding (HRB) were performed on a new blood sample to elucidate the aberration. When mosaicism was suspected, the number of analysed metaphases was increased to a total of 115 and an additional analysis of 200 metaphases was done on a second blood sample.

RESULTS

A chromosomal abnormality was demonstrated in 0.58% (95% CI: 0.28-1.19) of cases which did not differ significantly from that reported in female newborns (0.79%; 95% CI: 0.68-0.94). Balanced reciprocal translocation was observed in 0.4% of patients (n = 5), paracentric inversion of chromosome X in 0.08% (n = 1) and gonosomal mosaicism in 0.08% (n = 1). However, chromosomal aberrations were less common among females with primary infertility compared to those with secondary infertility (0.25 versus 1.25%, P = 0.04).

CONCLUSIONS

The present study suggests that routine cytogenetic analysis cannot be advocated in normovulatory infertile women. Nevertheless, the relatively higher frequency of abnormal karyotypes in women with secondary infertility indicates that this subgroup of patients might benefit from a routine karyotype analysis.