The pin-hole cervical os; a small fertility problem

24 women with a so-called pin-hole cervical os during the pre-ovulatory phase of the menstrual cycle were detected in a group of 850 infertile couples. This cervical condition is rarely seen and is often combined with extreme oligomucorrhea and poor cervical mucus qualities. Sperm quality was so poor in four couples that they were excluded. Nine women were likely to have been exposed to diethylstilbestrol (DES) in utero. The pregnancy rate in this group was poor, only two pregnancies by coitus and none by intra-uterine AIH. In the other eleven women there was a strong correlation between a good result of the post-coital test (PCT) and the chance to achieve pregnancy. Four of the eight women with a good result of the PCT became pregnant by coitus. The three women with a poor result of the PCT became pregnant by intra-uterine AIH. It is possible that the fertility prognosis of a woman with a pin-hole cervical os during the pre-ovulatory phase of the menstrual cycle is unfavourably influenced by DES exposure in utero. A pin-hole cervical os in the pre-ovulatory phase of the menstrual cycle, without DES exposure, has probably no influence on fertility.