Minimal stimulation (ms) natural cycle IVF
Sep 05 • 2014

The use of new medications to minimise the risk of premature ovulation has allowed the success rates from MS IVF to improve significantly

MS IVF does, however, have several advantages over conventional IVF and may be a reasonable and appropriate choice for selected patients like:

  • Women who do not respond to standard drug regime
  • Women who, despite higher dosage of stimulation, produce only 1-2 follicles
  • Women who are at risk of ovarian hyperstimulation
  • Women who ethically and morally do not want to create excess embryos.

How does minimal-stimulation IVF differ from conventional IVF?

IVF involves a number of steps:

  • Stimulation of the ovaries with medication to allow multiple eggs to develop
  • Retrieval of the eggs from the ovaries
  • Fertilisation of the eggs with sperm and culturing of the embryos in incubators
  • Transferring the embryo/s into the uterus.

Both conventional and minimal-stimulation IVF are essentially identical in steps 2, 3 and 4.

The protocols differ with ovarian stimulation (step 1). In conventional IVF, varying doses of hormones are injected daily for several days in order to yield multiple follicles and eggs.

In minimal stimulation, specialists use low injectable stimulation and/or oral medications, or a mixture of both.

What are the advantages of MS IVF?

Comfort and convenience

MS IVF involves the use of fewer medications, and lower doses of medication, than conventional IVF. Patients doing conventional IVF protocols are monitored with blood hormone tests and vaginal sonograms every 24 – 72 hours. With MS IVF, fewer monitoring visits are required, thus reducing patients’ inconvenience and stress.


The use of fewer medications, and lower doses of these medications, often results in a significant cost savings for patients.

Side effects and risks for ovarian hyperstimulation syndrome (OHSS)

The injectable ovarian-stimulation medications used in conventional IVF cause some patients to experience significant side effects, such as bloating, fatigue, and breast tenderness. In a small percentage of patients, these medications can lead to ovarian hyperstimulation syndrome (OHSS), a condition in which the ovaries can become markedly enlarged and fluid can accumulate in the pelvis, abdomen and chest cavities. Whilst the majority of OHSS cases are usually mild and resolve quickly, some patients require hospitalisation for intravenous fluids and may require procedures to remove fluid from the pelvis and abdomen. Blood-thinning medications are used to prevent dangerous blood clots from forming.

As compared to conventional IVF, the chances of developing OHSS with MS IVF are greatly reduced.


In MS IVF, a patient commonly develops only one or two follicles and may be able to undergo egg retrieval with local anaesthesia. Therefore patients can save the cost of any anaesthesia fees.

Ethical concerns

Some patients and couples are ethically, religiously or morally opposed to the cryopreservation of embryos. MS IVF generates fewer embryos than conventional IVF, in most cases making it unnecessary to consider or employ cryopreservation.

Other possible advantages

Proponents of minimal stimulation IVF believe that the high doses of ovarian stimulation hormones used in many conventional IVF cycles might reduce the chances of fertilisation, implantation and pregnancy. Data is limited and conflicting at this time. Further research is required to make conclusions regarding the superiority of one method over another in selected patient groups.