Doxycycline treatment and human infertility.

The role of mycoplasmas in infertility was studied in 120 couples. During the twelve months of the study 27 couples (22-5%) conceived. T mycoplasmas were isolated from 63% of these couples, and Mycoplasma hominis from 18%, compared with 56% and 13%, respectively, in those who did not conceive. 88, with primary infertility of unascertained cause, took part in a controlled trial with doxycycline. The couples in the trial were allocated randomly to three groups: 30 received doxycycline, 28 received a placebo, and 30 couples were untreated. Although a twenty-eight-day course of doxycycline eradicated M. hominis and T-strain mycoplasmas from 27 (96%) of the 28 couples harbouring them, the rate of conception was no higher in those treated with the drug than in control groups. It is concluded that mycoplasmas are not associated with primary infertility and that, although doxycycline eradicates them, this drug is of no benefit in the treatment of primary infertility of unascertained cause.