What Is The Difference Between Conventional Egg Freezing and “Minimal Stimulation” Egg Freezing?

Freeze’s “Eggspert” Answers series provides women answers to common, important questions they have when considering to freeze their eggs - answered by world-renowned medical experts. This post is answered by Freeze and Dr. Daniel Kort, Reproductive Endocrinologist at Neway Fertility in NYC.


In any given month, most women grow and develop one egg, contained within a small fluid filled sac known as an ovarian follicle. This one egg is “selected” from a cohort of eggs, resting in a group of small follicles within the ovary. Women undergoing the egg freezing process are stimulated so that more than one egg grows, matures, and can be successfully retrieved and frozen. Such stimulation can be accomplished in different ways.

With minimal stimulation egg freezing, you may not have to give yourself injections at all.

With minimal stimulation egg freezing, you may not have to give yourself injections at all.

Conventional Egg Freezing

Traditionally, women are given relatively high doses of medications called “gonadotropins,” which are actually copies of hormones naturally produced by the pituitary gland. When given at supraphysiologic doses (higher amounts than found naturally), these drugs cause multiple follicles to develop, each containing an egg. For most women freezing their eggs, this conventional method is best, as it produces the most eggs that can be retrieved and frozen. However, conventional stimulation also has the highest chance of significant side effects. While most women tolerate the medications well and have only mild side effects (minimal bloating and discomfort), some women have significant side effects (pain, bloating, dehydration) and cannot tolerate this treatment. Furthermore, although now very rare, some women can develop a condition known as Ovarian Hyperstimulation Syndrome (OHSS), with severe pain and dehydration, sometimes requiring hospital admission.

Women who choose minimal stimulation egg freezing take lower doses of hormone injections compared to conventional egg freezers, or take pills only.

Women who choose minimal stimulation egg freezing take lower doses of hormone injections compared to conventional egg freezers, or take pills only.

Minimal Stimulation Egg Freezing

Alternatively, women can undergo “minimal stimulation” (or “min stim”) by taking pills, such as Clomid or Letrozole, or very low doses of gonadotropins. These medications also cause multiple follicles to develop, yet usually fewer than with conventional stimulation. There are two main groups of patients that should choose this alternative route. First, patients that have previously taken high doses of gonadotropins and experienced severe side effect or OHSS. Using minimal stimulation, the risk of these complications is nearly zero. Second, patients that have taken high doses of gonadotropins and developed only a small number of follicles. These patients typically respond equally well with minimal stimulation as with conventional stimulation, which are expensive and require daily injections.

With minimal stimulation, women may retrieve a lower number of eggs per egg freezing cycle, but they’re at lower risk for side effects.

With minimal stimulation, women may retrieve a lower number of eggs per egg freezing cycle, but they’re at lower risk for side effects.

Weighing Your Options

When deciding on a stimulation strategy for egg freezing, doctors must understand a woman’s history, goals, and priorities. Based on her entire clinical picture, a patient should be given her options, along with a final recommendation. While conventional stimulation is the best option for most, minimal stimulation can also be a great option for the properly selected patient.


Daniel_Kort_MD

Dr. Daniel Kort is double board-certified in Obstetrics and Gynecology as well as Reproductive Endocrinology and Infertility. He is a member of the American Society for Reproductive Medicine (ASRM) and the American Congress of Obstetricians and Gynecologists (ACOG). He has published extensively on reproductive aging, pregnancy in older women, and polycystic ovary syndrome.

Dr. Kort helps women freeze their eggs at Neway Fertility, who is a sponsor of this post. Learn about Neway’s egg freezing practice, including how to book an appointment, here —>