The role of microbiology in infertility

Infertility is characterized by the inability to achieve a successful pregnancy, taking into account the patient's medical, sexual, and reproductive history, age, physical findings, diagnostic tests, or a combination of these factors. Infertility is a multifactorial condition that can be caused by both male and female factors. In many cases, medical intervention is necessary for the couple to achieve pregnancy. One of the potentially treatable causes is female genital tract infections. Several infectious agents are currently known, among which Ureaplasma parvum and Mycoplasma hominis are two agents whose treatment could benefit patients in achieving pregnancy. The objective of this study was to analyze the effect of antibiotic treatment on women seeking pregnancy, and our primary outcome is the achievement of pregnancy.

Data were collected from 334 women seen at the Fertility Clinic of the Gynecology and Obstetrics Service during the period February/2020-March/2024. The variables analyzed were: type of infertility (primary or secondary), previous births, previous abortions, previous ectopic pregnancies, possible causes of infertility, previous use of contraceptives, time since discontinuation of contraceptives, microbiological isolates, antibiotic treatment, and pregnancy achievement.

The median age of the women treated was 34 years (IQR 31, 39 years; minimum 24, maximum 47). In most cases, infertility was primary (74.6%). In 21.8% of cases, no apparent cause of infertility was identified; when one could be identified, the most common causes were male factor (17.7%), chronic anovulation or polycystic ovary syndrome (14.8%), endometriosis (14.0%), and tubal factor (12.15). In 34.2% of cases, multiple causes of infertility were identified. The median time to conception was 17 months (IQR 10, 36 months). Most women had previously used contraceptives (57.1%). Microbiological studies were performed in 89 women (26.6%). The majority of samples analyzed were vaginal swabs (88%), followed by endometrial biopsies (8.6%), endocervical swabs (3.1%), and uterine biopsies (0.3%). Forty-eight point five percent of bacteriological cultures were positive, with the most notable isolation of Ureaplasma urealyticum/parvum (33.9%), Gardnerella vaginalis (17.4%), and Streptococcus agalactiae (16.1%). Mycological cultures were positive in 14.1% of cases, with the most notable isolation of Candida albicans (79.6%). Regarding the STI PCR test, 32.7% had a positive result, with detection of Ureaplasma parvum (76.9%), Mycoplasma hominis (11.5%), and Ureaplasma urealyticum (10.3%). No cases of active Chlamydia trachomatis or Neisseria gonorrhoeae infection were detected. Of the women with a positive microbiological result (56.2%), more than half (54%) received antibiotic treatment, and of these, 40.7% achieved pregnancy. Of the women who did not receive antibiotic treatment (46%), 56.5% achieved pregnancy. On the other hand, of the women without a positive microbiological result (56.2%), 54% received antibiotics, and of these, 40.7% achieved pregnancy. Of the 46% who did not receive antibiotics, 56.5% achieved pregnancy.

Further studies are needed to assess microbiological isolation and antibiotic treatment in infertile women.