Understanding stimulation protocols

Stimulation is often the first phase of IVF that feels unmistakably real: needles, monitoring appointments, and a schedule that can change overnight. If the protocol names and medication doses all sound interchangeable, you are not alone.

This guide explains the most common patterns in plain language so you can follow along in the app, ask sharper questions, and worry less about whether you missed something obvious. It is not a substitute for your clinic's instructions — every protocol is individualized.

In a natural cycle, your body typically selects one dominant follicle and releases a single egg at ovulation. IVF needs several eggs maturing at once, because not every egg will fertilize or become a viable embryo.

Ovarian stimulation uses injectable hormones — usually forms of follicle- stimulating hormone (FSH), sometimes with added LH activity — to recruit and grow multiple follicles in the same cycle. Each follicle is a small fluid-filled sac that should contain one egg. The goal is not the highest possible number, but a cohort of mature eggs your clinic can retrieve safely.

Stimulation rarely starts on a random Tuesday. Most cycles begin with baseline testing — a transvaginal ultrasound to count resting follicles and check for cysts, plus bloodwork for hormones like estradiol and sometimes progesterone.