Minimal and Natural In Vitro Fertilization (IVF)


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Minimal and Natural In Vitro Fertilization (IVF)


Several years ago, a couple of centers reported that if a woman had a follicle stimulating hormone (FSH) level over 15, her success rate with IVF was essentially zero. Since then, most physicians held strongly to this belief when advising women as to their best options for having children. Over the ensuing years, throughout the world, many groups challenged this hypothesis, based on the belief that nature provides a mechanism for selecting good eggs that is over-ridden by the strong stimulation protocols used in conventional in-vitro fertilization (IVF). The concept of “minimal” and natural IVF has developed as a result of this work, and indeed, it has been shown that women with poor prognoses, such as those with high FSH levels can conceive viable pregnancies.

Physiology of Ovulation

The accepted belief is that women are born with a given number of eggs and follicles.  Some of these will ultimately grow into a mature egg that can be released from the ovarian follicle and be fertilized by a sperm.  As time goes on, the number of follicles and early eggs slowly decrease each month.  When a female reaches puberty, the cyclic release of FSH and other hormones from the brain (or the pituitary gland) help to stimulate the growth and selection of a single ‘dominant’ follicle that is most efficient at using FSH while the other smaller follicles undergo a process of dying called atresia. In-vitro fertilization (IVF) stimulation protocols use high doses of FSH to salvage these follicles destined to die. That is why the majority of eggs obtained in an IVF cycle do not produce high quality embryos or viable babies. Still, for women who respond well to these drugs, conventional IVF still offers the best chance for success in a single attempt. Furthermore, the frozen embryos that result from many of these cycles increase the efficiency of the process if pregnancy does not occur or the couple desires a sibling later on.

For women with elevated FSH levels, previously poor responses, and recurring poor embryo quality, the cost and side effects of high-dose protocols may not be worthwhile. While controversial, some physicians believe that these protocols may lower egg vitality or decrease uterine receptivity, making this approach even less desirable for these poor prognosis patients.

Philisophical Approach

The keys to success with minimal or natural IVF are individualization of treatment and patience. Each woman’s situation must be considered separately in deciding what protocol to use. Patients and clinicians need to be patient and understand that there will be set-backs like failed egg retrievals and cancelled cycles. However, since the emotional, physical, and financial costs of commencing these cycles is relatively low, it is easier for women to get back into treatment and try again quickly.

Natural Cycle IVF

As the name implies, natural cycle IVF uses no drugs to facilitate egg production. The cycles are not totally natural, because a single injection of human chorionic gonadotropin (hCG) or Lupron is used to prepare the egg for retrieval. Occasionally an antagonist is used to prevent pre-mature ovulation. Progesterone supplementation is still given after the egg retrieval. Candidates for natural cycle IVF include women with a poor prognosis including those with high FSH levels or low anti—Mullerian hormone (AMH) levels. The addition of FSH stimulation medications often does not affect ovaries already saturated with the body’s own FSH.

Minimal IVF

With minimal IVF, the oral medication clomiphene citrate (Clomid) and low doses of injectable hormones are used to obtain a small number of eggs and avoiding premature ovulation, while avoiding hyperstimulation. Examples of potential candidates would be women who do not produce larger numbers of eggs on higher doses and women with poor egg quality in prior cycles.

Other Benefits of Minimal and Natural IVF

Since small numbers of eggs are retrieved, many women can undergo these procedures with sedation only, thus reducing the cost and risk of anesthesia.  In addition, since the egg numbers are low, the procedure is often quicker and the incidence of post-procedure internal bleeding; a rare but finite complication of conventional IVF, is thought to be decreased.


Over the years, the doctors at HRC Fertility have performed these procedures on selected patients. Until now, we have not offered this as a comprehensive program and have not singled out these patients in our SART report. While Minimal and Natural Cycle IVF represent options for selected patients, one should assume that the pregnancy rates will be lower when compared to conventional IVF. Lower pregnancy rates are expected, since fewer embryos are transferred, more retrieval failures are seen, and the patients themselves usually have a poor prognosis by conventional standards. Thus, we still believe that conventional IVF is the treatment of choice for women who can respond appropriately to stimulation.

The following women should consider Minimal or Natural IVF as an option:

  1. Any woman with FSH greater than 10 and previously poor responses to stimulation.
  2. Women over age 40 with FSH greater than 10.
  3. Poor responders, despite normal FSH levels.
  4. Women with repeated poor embryo quality.

For more information on the Minimal and Natural IVF program at HRC Fertility Rancho Cucamonga, please contact us via our online form or call us at (909) 941-1120.