Few eggs
If only a few eggs develop during conventional stimulation, or only a few blastocysts form after fertilisation, the DuoStim significantly increases the yield.
DuoStim – a double chance in the same cycle.
By DuoStim we mean a stimulation in the second half of the cycle – directly following a stimulation and egg retrieval in the first half of the cycle. This makes it possible to obtain significantly more eggs within one month than with conventional stimulation.
Special topic
What is a DuoStim and when does it make sense?
The DuoStim allows us to obtain significantly more eggs within one month. It is particularly interesting for women and couples in whom only a few eggs develop during conventional stimulation, or in whom only a few blastocysts form after egg fertilisation.
Indications
When a DuoStim makes sense.
Preimplantation genetic testing
In the context of preimplantation genetic testing, the number of testable embryos can be increased – and with it the chance of healthy embryos.
Fertility & cancer
If oncological therapy is necessary, the limited time can be used optimally with a DuoStim to obtain as many eggs as possible.
The procedure
How a DuoStim works.
Within 4–5 weeks we can obtain significantly more eggs than in one month with a conventional stimulation.
1
First stimulation
The woman begins her first stimulation on day 3 of her cycle. This takes a little less than two weeks.
2
First egg retrieval
Once enough follicles are present, the first egg retrieval is performed. The eggs are fertilised and frozen as blastocysts.
3
Second stimulation
About 4–5 days after the first egg retrieval, the second stimulation begins. It again takes around two weeks and typically results in a similar number of eggs as the first.
4
Freezing & transfer in a subsequent cycle
No embryo transfer is possible after the first stimulation, because the second stimulation continues immediately afterwards. The blastocysts obtained from both stimulations are frozen and returned to the uterus in a subsequent cycle.
Medical background
Why two stimulations in one cycle are possible
For a long time it was assumed that only a single group of follicles can mature per cycle. Research in recent years has changed this picture: several cohorts of small follicles are apparently recruited in the ovary in waves – including in the second half of the cycle, that is, after ovulation or after an egg retrieval.
The DuoStim makes use of exactly this observation. Instead of letting a whole month pass, a second cohort – still present in the ovary at this point – is stimulated directly after the first retrieval. For women with a severely reduced egg reserve, this is decisive: each individual stimulation yields only a few eggs, and the total number of available eggs largely determines whether a viable blastocyst develops in the end.
What we say about DuoStim – and what we do not
The available research suggests that eggs from the second, luteal stimulation are not inferior to the eggs of the first stimulation in their developmental potential. Reliable figures on the chances of success, however, depend heavily on age, egg reserve and medical history. We therefore deliberately do not quote blanket percentages, but discuss your individual starting position on the basis of your own findings.
In comparison
DuoStim and conventional stimulation.
Conventional stimulation
One stimulation per cycle, one egg retrieval, followed as a rule by a break of one or more cycles. If a fresh transfer is possible, the embryo can be transferred in the same cycle – making the path to pregnancy short.
For women with a normal egg reserve, this is the proven standard path. If each stimulation yields enough eggs and blastocysts, doubling brings no additional benefit and would only be an additional burden.
DuoStim
Two stimulations and two egg retrievals within about four to five weeks. All embryos are frozen as blastocysts ("freeze-all"); the transfer takes place in a subsequent cycle, in which the uterine lining is built up without time pressure.
The gain lies in the numbers: more eggs in less time. This is relevant when time is short or when a single stimulation yields too few eggs for a realistic chance. The downside is a dense schedule of appointments and a higher amount of medication.
A realistic view
When a DuoStim is not the right path
We do not recommend the DuoStim across the board. It is a tool for specific situations – and in others it is not a good idea:
- With a good egg reserve: if one stimulation yields enough eggs and blastocysts, the second round brings no additional benefit.
- With an increased risk of overstimulation: for example in PMOS (formerly polycystic ovary syndrome) with a high egg reserve, we choose other, gentler stimulation concepts.
- If the burden is too high: two retrievals and a dense sequence of monitoring appointments within a few weeks are physically and emotionally demanding. This has to fit into your everyday life.
- With unclarified findings: if, for example, there is an untreated condition on the side of the uterus or significantly reduced sperm quality, this needs to be clarified first.
We tell you clearly in advance what to expect in these weeks: more ultrasound and blood checks than with a single stimulation, two procedures in short succession, a higher amount of stimulation medication – and no embryo transfer in this cycle, because the blastocysts are frozen.
Legal framework
What to consider in Austria
The DuoStim is not a separate form of treatment with its own set of rules, but a variant of the stimulation within an IVF or ICSI treatment. The general provisions of the Reproductive Medicine Act therefore apply:
- Medically assisted reproduction is permitted within a marriage, a registered partnership or a cohabiting relationship.
- Fertilised eggs may be stored cryopreserved until revoked, but for a maximum of ten years – this applies to the frozen blastocysts from both stimulations.
- Preimplantation genetic testing is only permitted in certain legally defined cases; whether it is an option in your situation is something we clarify with you and our geneticists.
- Anonymous sperm or egg donation is not permitted: from the age of 14, the child has the right to information about the identity of the donor.
- Surrogacy is prohibited in Austria.
As of 2026. Details and their practical interpretation can change – in the consultation we clarify what specifically applies to you. You can also find an overview on our page about the legal framework.
Why the DuoStim needs its own laboratory
Two stimulations in four to five weeks only work when the laboratory, cryopreservation and scheduling go hand in hand. We have been a pioneer of reproductive medicine in Austria since 1982/83, co-developed the technique of cryopreservation in 1991 and work with our own on-site genetics laboratory. More than 30,000 children have been born with our support.
FAQ
Frequently asked questions about the DuoStim.
Is a DuoStim twice as demanding as a normal stimulation?
The effort is considerably higher: two egg retrievals, more monitoring appointments and a larger amount of stimulation medication within about four to five weeks. Many women nevertheless find it a relief to achieve the result of two cycles in one month instead of waiting over several months. We discuss realistically in advance what to expect.
Are the eggs from the second stimulation of poorer quality?
The available research suggests that the eggs from the second, luteal stimulation are not inferior to the eggs of the first stimulation. They come from a further cohort of small follicles that is present in the ovary anyway. Definitive figures depend on your individual situation.
Why is no embryo transfer possible in the DuoStim cycle?
Because the second stimulation begins immediately after the first egg retrieval. The hormone doses required for it stand in the way of building up the uterine lining. All blastocysts are therefore frozen and transferred in a specially prepared subsequent cycle – an approach that has advantages in its own right.
For whom is a DuoStim particularly worthwhile?
Above all for women with a severely reduced egg reserve, for couples in whom only a few blastocysts develop from one stimulation, for treatments with planned preimplantation genetic testing and for patients for whom time is pressing – for example before oncological therapy. You can read more on our page Fertility and cancer.
Does the DuoStim increase the risk of overstimulation?
Because all embryos are frozen in the DuoStim cycle as a matter of principle and no fresh transfer takes place, a major risk factor for severe ovarian hyperstimulation syndrome is eliminated. In women with a high egg reserve and a corresponding risk profile, we nevertheless do not use the DuoStim, but choose gentler concepts.
How many eggs can I expect?
This cannot be predicted reliably. The yield depends above all on age, egg reserve (including the AMH value and the number of antral follicles on ultrasound) and the course of the first stimulation. As a guide: the second stimulation typically yields a similar number of eggs as the first. We derive concrete expectations from your own findings.
Can a DuoStim be repeated?
In principle yes, if it is medically sensible and you feel ready for it. Between two DuoStim treatments, we plan in a recovery phase. Whether a repetition actually improves the chances depends on what the first treatment yielded in terms of eggs and blastocysts – we assess this together with you.
Can the DuoStim be combined with preimplantation genetic testing?
Yes, this is one of the most common indications: more blastocysts mean more testable embryos and thus a higher chance of finding an unaffected embryo. In Austria, however, preimplantation genetic testing is only permitted in certain legally defined cases. We examine this together with our geneticists in our own laboratory (as of 2026).
Your next step
Let's talk about your options.
Whether a DuoStim makes sense for you is something we are happy to clarify in a personal consultation.
Or call us: +43 1 877 77 75