What initial investigations should I perform for a couple presenting with infertility after one year of unprotected intercourse?

Initial investigations for a couple presenting with infertility after one year of unprotected intercourse should include simultaneous assessment of both partners.

For the male partner, a semen analysis is the first-line investigation. The sample should be collected by masturbation into a clean, non-toxic container after 2 to 7 days of sexual abstinence, ideally near the laboratory to avoid temperature fluctuations and delays. If the first semen analysis is abnormal, a repeat test should be performed ideally 3 months later, or sooner if there is severe sperm deficiency. Men with two abnormal semen results should be referred for further assessment. Screening for chlamydia is also recommended in men.

For the female partner, initial investigations include measurement of mid-luteal phase serum progesterone (around day 21 of a 28-day cycle) to confirm ovulation, even if menstrual cycles are regular. Women with irregular or prolonged cycles may require repeated progesterone measurements and gonadotrophin (FSH and LH) levels to identify ovulation disorders. Thyroid function tests and prolactin measurement should be reserved for women with symptoms suggestive of thyroid disease or ovulatory disorders, respectively.

Screening for Chlamydia trachomatis should be offered before any uterine instrumentation. Women without known comorbidities (such as pelvic inflammatory disease, endometriosis, or previous ectopic pregnancy) should be offered hysterosalpingography (HSG) or hysterosalpingo-contrast ultrasonography to assess tubal patency. Women with suspected comorbidities should be offered diagnostic laparoscopy with dye to assess tubal and pelvic pathology.

Routine use of postcoital testing, basal body temperature charts, endometrial biopsy, and screening for antisperm antibodies is not recommended.