Charting the Menstrual Cycle
The initial examinations of the woman include charting the menstrual cycle. The purpose of this examination is to determine whether there are any abnormalities in the ovarian function, whether ovulation occurs, and whether the function of the corpus luteum is sufficient for pregnancy. These will be determined by means of blood samples collected at different stages of the menstrual cycle.
In the early stages of the cycle (usually 2 to 5 days into the cycle), blood samples are collected for determining the levels of hormones which control ovarian function (such as the follicle-stimulating hormone (FSH), the luteinizing hormone (LH), and prolactin, or the milk producing hormone). The sample will also be analyzed for the thyroid-stimulating hormone (TSH).
Since the rate of prolactin secretion varies over the course of 24 hours, the sample will be collected in the morning between 10.00 am and 12.00 noon. Physical exercise and intercourse the previous night should be avoided before sampling.
Approximately seven days after a positive ovulation test, a blood sample will be collected for determining the level of progesterone (PROG).