Login/ Portal For Embryologists For IVF Clinics Blog Download Contact Archive

Customized IVF Cycles: Mini-STIM, Natural Cycle FET, and Vaginal Progesterone

Natural Cycle FET and Vaginal Progesterone

Once the ovarian follicles have achieved an adequate size and stage of development, a trigger injection is given to induce the final maturation of the eggs. The timing of this injection is very important to the outcomes of your in vitro fertilization (IVF) cycle and needs to be precise. Mini-STIM, Natural Cycle FET, and Vaginal Progesterone. An egg retrieval procedure is then scheduled for 36 hours following this injection.⁠

When the hCG trigger is administered too early or too late, or too low a dosage of hCG is administered the result can be an increase in the percentage of immature (M-I) or mature M-II (but aneuploid), eggs at retrieval. ⁠

Have you discussed alternate IVF treatments with your reproductive endocrinologist? ⁠

Mini-IVF (also known as micro or minimal stimulation IVF) is similar to conventional IVF in the procedures used during treatment, but mini-IVF uses weaker medications or lower doses of medications to produce only a few eggs. It may also be done without any ovarian stimulating drugs.⁠

Because lower amounts of fertility drugs are used, the cost per cycle is lower, and the risk of ovarian hyperstimulation syndrome (OHSS) is reduced.⁠


With frozen embryo transfer, it’s crucial that the timing of transfer occur when a woman’s endometrium is receptive, meaning an embryo can implant. The protocols used to prepare the endometrium for embryo transfer vary more than most of us would imagine — there is truly no standardization, and each clinic you visit might approach this in a different way. Patients undergoing FET may not require hormonal supplementation if normal follicular development and ovulation is observed. ⁠


Mini-STIM, Natural Cycle FET, and Vaginal Progesterone. Doctors usually prescribe progesterone supplementation to start on the day the eggs are harvested. If pregnancy takes place, the doctor may tell you to continue taking progesterone throughout the first trimester. Progesterone can be taken as an intramuscular injection or vaginally (suppositories, gel, or vaginal tablets). There appears to be no difference in the chances of becoming pregnant or continuing a pregnancy if progesterone is given by injection or intravaginally. You should talk to your doctor about which form of progesterone will better fit your needs.⁠