Professional and Linguistic Assessments Board (PLAB) Practice Exam

How is ovulation typically investigated?

1. Counting days from the menstrual cycle

2. Subtracting 7 from the cycle length

3. Measuring follicle size

4. Using a luteinizing hormone (LH) test

The correct answer is: Subtracting 7 from the cycle length

In investigating ovulation, using a luteinizing hormone (LH) test is a highly effective method. The LH surge plays a crucial role in triggering ovulation; it typically occurs 24 to 36 hours prior to the release of the egg from the ovary. By measuring LH levels through urine or blood tests, healthcare providers can ascertain when ovulation is likely to happen, which is particularly useful for individuals trying to conceive or monitoring their menstrual cycles for fertility awareness. Counting days from the menstrual cycle can provide a general guideline for when ovulation might occur, especially with regular cycles, but it lacks the specificity offered by hormonal testing. Subtracting 7 from the cycle length assumes a constant luteal phase, which may not be accurate for every individual. Measuring follicle size through ultrasound helps assess ovarian function and follicular development but is not as directly indicative of the timing of ovulation as the LH test. Therefore, while all options can contribute to understanding ovulation, the LH test is the most reliable and immediate method for determining the actual time of ovulation.