Читать книгу Assisted Reproduction Techniques - Группа авторов - Страница 211

Cervical stenosis is a rare problem, occurring in about 1% of women presenting for embryo transfer (ET) [1]. It has been defined as an external cervical opening of less than 2.5 mm [2], but clinically it manifests as the inability to pass instruments such as dilators and hysterosalpingography (HSG) or ET catheters easily through the cervical canal [3]. Some women with cervical stenosis may have associated dysmenorrhea or even amenorrhea, but most are asymptomatic, so presumably the cervical canal is adequate for the passage of menstrual blood but not instruments [4–7]. Also, it is not just the diameter of the cervical opening but also the tortuosity of the canal as well as the degree of uterine flexion or version that determine the difficulty in inserting instruments [3].

Cervical stenosis could be congenital or acquired. Congenital cases could result from diethylstilbestrol (DES) exposure in utero, while acquired cases could be caused by previous cervical surgery such as cone biopsy, loop excision or trachelectomy [3]. However, many women with cervical stenosis have no such history.

Cervical stenosis is associated with difficult ET [4–7], which in turn is associated with a significantly lower pregnancy rate when compared with easy transfers [8,9].