Endometrial nerve fibre density in patients undergoing IVF: a pilot study

The presence of nerve fibres in the functional layer of the endometrium has been strongly associated with endometriosis. Presence of nerve fibres in the endometrium of women undergoing IVF has not been previously assessed. This prospective pilot study assessed the presence of nerve fibres in endometrium of women undergoing IVF due to various causes and examined the correlation between the presence of nerve fibres and IVF success. A total of 32 IVF patients underwent endometrial biopsy during days 21–23 of the menstrual cycle. Nerve fibres were identified by immunohistochemical staining. Correlations between the presence and density of nerve fibres and aetiology of infertility and IVF success were measured. Nerve fibres were identified in the endometrium of 10/31 (32.3%) women with a satisfactory biopsy. Presence of nerve fibres was not correlated with cause of infertility. Clinical pregnancy was achieved in 12/32 (37.5%) patients, without correlation to presence of nerve fibres in the endometrium. Nerve fibres were identified in a substantial percentage of women undergoing IVF, possibly reflecting underdiagnosis of endometriosis in this population. The presence of nerve fibres does not appear to interfere with implantation. The significance of nerve fibres in the endometrium of IVF patients warrants further research.The presence of nerve fibres in the functional layer of the endometrium has been strongly associated with endometriosis. The presence of nerve fibres in the endometrium of women undergoing IVF has not been previously assessed. Our aim was to assess the presence of nerve fibres in endometrium of women with various causes of infertility undergoing IVF and to examine the association between the presence of nerve fibres in the endometrium and IVF success. In a prospective study, 32 IVF patients underwent endometrial biopsy during days 21–23 of the menstrual cycle. Nerve fibres were identified by immunohistochemical staining. Associations between the presence and density of nerve fibres and the aetiology of infertility and IVF success were measured. Nerve fibres were identified in the endometrium of 10/31 (32.3%) women with a satisfactory biopsy. No association was found between the presence of nerve fibres and the cause of infertility. Clinical pregnancy was achieved in 12/32 (37.5%) patients, without association with the presence of nerve fibres in the endometrium. Nerve fibres can be identified in a substantial percentage of women undergoing IVF, possibly reflecting underdiagnosis of endometriosis in this population. Their presence does not interfere with embryo implantation. The significance of nerve fibres in the endometrium of IVF patients warrants further research.