A 26 year old woman with regular menses and her 28 year old partner comes to the GP surgery complaining of primary infertility. She and her husband have been trying to achieve pregnancy for more than 2 years and have been unsuccessful. She has a regular 28 day menstrual cycle. Her BMI is 23. What is the SINGLE most appropriate investigation to determine if she is ovulating?
A. Basal body temperature charts
B. Cervical smear
C. Day 2 follicular stimulating hormone (FSH) and luteinizing hormone (LH)
D. Day 21 progesterone
E. Endometrial biopsy
Day 21 progesterone which is the mid-luteal progesterone level is used to assess ovulation. If this is low, it may need repeating, as ovulation does not occur every month.
FSH and LH should be measured if there is menstrual irregularity: High levels may suggest poor ovarian function. A comparatively high LH level relative to FSH level can occur in PCOS. In reality, we would obtain FSH, LH and mid-luteal progesterone levels. But for the purpose of examination, always pick mid-luteal progesterone levels as the answer when it comes to infertility investigations.
Basal body temperature charts are not recommended to predict ovulation, as they are unreliable.
Causes of female infertility • Unexplained • Ovulation failure • Tubal damage • Note that a history of pelvic inflammatory disease is highly suggestive of damage to tubes
Basic investigations • Serum progesterone 7 days prior to expected next period. Meaning day 21 of a 28 day cycle. However, this day will need to be adjusted for different lengths of cycle • This is also termed “Mid-luteal progesterone level “ • It is done to assess ovulation: • If low, it may need repeating, as ovulation does not occur every month