Fertility Treatment Monitoring

Follicle and blood monitoring is an essential part of fertility treatment — for example, in IVF (in-vitro fertilization) and IUI (intrauterine insemination).

During follicle monitoring, ultrasound is used to track how the follicles in the ovaries are developing, and alongside it a blood test checks hormone levels — estrogen, progesterone, and LH. This lets the doctor gauge how the ovaries are responding to hormonal treatment and follow the follicles’ development, in order to pin down the right time for the ovulation-trigger injection (hCG) and for egg retrieval (in IVF), or to time intercourse or insemination.

How monitoring works

• Starting the monitoring — it usually begins on the second or third day of your period, to confirm you’re at the start of the cycle.
• Periodic ultrasound scans — several ultrasounds are done through the cycle to measure the size of the follicles and make sure they’re developing properly, in line with the treatment.
• Hormonal blood tests — alongside the ultrasound, blood is drawn to measure hormone levels (estradiol, LH, progesterone), to assess the ovaries’ response and confirm the follicles are developing normally.
• Deciding on the hCG injection — when a follicle (or several) reaches a suitable size (usually 18–20 mm), you’re given an hCG injection to trigger ovulation. Sometimes, in treatments other than IVF, the injection can be skipped and natural ovulation tracked instead.
• Egg retrieval, or insemination / timed intercourse — after the hCG injection or once natural ovulation is detected, the egg retrieval is carried out in IVF, or intrauterine insemination / timed intercourse takes place, depending on the treatment plan.

Why monitoring matters

• Precise timing — closely tracking follicle development allows accurate timing of the hCG injection and of retrieval or insemination/intercourse, which raises the treatment’s chances of success.
• Preventing complications — monitoring makes it possible to catch ovarian overresponse (hyperstimulation) early, which can prevent complications and lead to adjusting the treatment plan.
• Assessing follicle quality — it provides information on the quality and development of the follicles, which can shape clinical decisions during treatment..

Accurate, professional follicle monitoring is critical to the success of fertility treatment and to giving each patient the best possible chance.