IVF Success Over Time: Why More Than One Cycle Can Matter
Key Takeaways
One unsuccessful IVF cycle is not a final verdict. Cumulative live-birth rates include the outcomes of further fresh and frozen embryo transfers, but they are population estimates rather than a promise for an individual. Age, infertility history and what happened during the first cycle help shape the next discussion.
Key evidence: Smith et al. — Repeat IVF treatment cycles (JAMA) De Neubourg et al. — Cumulative live birth and dropout over six IVF cycles (RBMO)
IVF Second Opinion: 5 Things to Review Before Trying Again
This video was recorded in French. English and Arabic dubbed audio and subtitles are available from the YouTube player settings.
Why One Cycle Is Not a Final Verdict
A single unsuccessful IVF cycle does not mean that every later attempt will also fail. It does, however, provide information that can make the next prognosis more personal than the estimate given before treatment began.
After a negative result, it can feel as though the whole treatment path has closed. IVF is not a pass-or-fail test: each egg retrieval and embryo transfer is one step in a longer course of treatment.
The first cycle also shows how the ovaries responded, how many eggs were mature, whether fertilisation occurred and how embryos developed. These findings cannot guarantee a different result next time, but they can change the questions that the clinical team asks.
What “Cumulative Success” Actually Means
Cumulative live-birth rate describes the chance of at least one live birth over more than one treatment step. The denominator matters: a study may count all fresh and frozen transfers from one egg retrieval, or it may follow several complete cycles.
Three terms are easy to mix up:
| Term | What It Measures | Clinical Context |
|---|---|---|
| Per-transfer rate | Live birth after one embryo transfer. | Describes that transfer, not all embryos from the retrieval. |
| Complete cycle | Live birth from one egg retrieval and the fresh and frozen transfers arising from it. | Describes the outcome of one retrieval. |
| Multi-cycle cumulative rate | At least one live birth over several complete cycles. | Describes a longer course of treatment. |
A per-transfer figure and a cumulative figure therefore answer different questions and should not be set side by side. While embryos remain frozen after a transfer, the complete cycle is not yet finished. See our guide to frozen embryo transfers.
What Large Registry Data Show: 1 to 6 Cycles
Large registry studies show that live births continue to accumulate when people undergo further cycles. They do not show that everyone should have six cycles, or that the average result applies to a particular patient.
In a UK registry analysis, Smith and colleagues followed 156,947 women through 257,398 ovarian-stimulation cycles. In that study a “cycle” meant one stimulation plus the fresh and frozen transfers from it. Live birth after the first complete cycle was 29.5%. After six complete cycles the prognosis-adjusted cumulative estimate was 65.3%; the conservative estimate, which counts everyone who stopped as having no later live birth, was 46.8%.
Age changed the curve substantially. Among women aged 40 to 42, the first-cycle live-birth rate was 12.3% and the prognosis-adjusted cumulative estimate after six cycles was 31.5%. The study used UK treatments from 2003 to 2010, so these figures are useful for understanding the pattern, not for predicting a current clinic or individual result. Our age-based outcomes page explains why clinical pregnancy and live birth also need to be kept separate.
Optimistic vs Conservative Estimates: Why Dropouts Matter
Published cumulative rates differ depending on how dropouts are counted.
- Optimistic estimates assume that people who stop would have had the same chance as those who continue. This may overestimate success because prognosis can influence the decision to stop.
- Conservative estimates count everyone who stops as having no later live birth. This may underestimate success because treatment can end for personal, practical or financial reasons as well as medical ones.
De Neubourg and colleagues followed live birth and discontinuation over six complete IVF/ICSI cycles in Belgium. A cumulative curve describes what may happen if treatment continues; real people may stop for many different reasons. Physical burden, emotional wellbeing, time and cost belong in the discussion alongside the medical prognosis.
Key Factors That Shape Individual Cumulative Prognosis
No population average can replace an individual assessment. Before treatment, your age and the cause and duration of infertility help frame the estimate. Once a first cycle has taken place, the number of eggs collected, how the embryos developed and whether any were frozen add useful information.
A UK model developed by McLernon and colleagues used linked records from 113,873 women. It produced one estimate from information known before treatment and another after the first embryo-transfer attempt.
- Before treatment: age, duration and cause of infertility, previous pregnancy, and whether IVF or ICSI was planned.
- After the first attempt: the same information, plus egg number, embryo stage, number transferred and whether embryos were cryopreserved.
Dr. Aksoy’s approach
An unsuccessful first cycle is both a treatment outcome and a source of information. Dr. Aksoy reviews ovarian response, egg maturity, fertilisation and embryo development before deciding whether the next plan should change. Cumulative estimates are not a reason to continue indefinitely: the possible medical gain must be weighed against the physical, emotional and financial burden for that person.
How Clinicians Use Prior Cycles to Refine the Next Plan
The first cycle may reveal something worth changing, but a change is not automatically an improvement. The clinical team should first identify the specific problem and whether evidence supports a different approach.
A review may cover:
- whether the ovarian response matched the expected response
- how many retrieved eggs were mature
- the fertilisation pattern and embryo development
- whether embryos remain for frozen transfer
- whether the uterine cavity or transfer plan needs review
Possible changes to stimulation, insemination or transfer should follow from that review. ICSI, a different trigger or a frozen-transfer protocol is not a routine answer to every unsuccessful cycle. Our guide to evidence-based IVF strategies explains the distinction.
Knowing When to Continue and When to Re-evaluate
There is no universal number of cycles that every person should attempt. The decision depends on the expected chance of benefit, what earlier cycles showed and what further treatment would ask of the patient or couple.
- Reasons to discuss continuing: embryos remain available, or the review finds a specific issue for which a reasonable adjustment is possible.
- Reasons to pause and reassess: repeated cycles provide little prospect of transferable embryos, the expected gain has become very small, or the burden of treatment is no longer acceptable.
For cost and next steps, see what usually changes the total cost of IVF and what to review after an unsuccessful cycle.
Conclusion
One result does not tell the whole story, but a cumulative percentage does not tell an individual story either. The useful question is not simply, “How many cycles?” It is, “What did we learn, what might change, and is the possible benefit worth the burden of continuing?”
Related Reading
- Ways to Improve IVF Success: Evidence-Based Strategies
- What Usually Changes the Total Cost of IVF?
- Failed IVF: What to Review Before the Next Cycle
- Frozen Embryos in IVF: When Freezing Helps and What the Tradeoffs Are
Frequently Asked Questions for Dr. Aksoy
How many IVF cycles does it take to get pregnant?
There is no single number that applies to everyone. Some patients become pregnant with the first transfer; others need several attempts. One of the most important factors is age. After 40 in particular, chromosomal abnormalities are more common in embryos, so achieving a pregnancy can be harder.
First, a distinction: an IVF cycle and an embryo transfer are not the same thing. Suppose one egg collection gives three embryos and we freeze them. If the first transfer fails, we may not need another egg collection to use the remaining embryos. So a single egg collection can give more than one chance of pregnancy.
I try to explain to patients not only the chance of the first transfer, but also the total chance of pregnancy we can reach with all the embryos we obtain. We call this cumulative success.
When the first attempt fails, I do not conclude straight away that the treatment does not work. I look at embryo development, the transfer process and any problems that can be corrected. Sometimes continuing with the same approach is right; sometimes the plan needs to change.
What matters to me is not telling a patient to do three or four attempts. It is making a realistic assessment of the chance of success after each attempt, with the information we have. Ovarian reserve, embryo quality and the chance of pregnancy are not the same for everyone.
FAQ
Does a single failed IVF cycle indicate that future cycles will also fail?
No. It provides information about that cycle, not certainty about every future cycle. The result should be reviewed alongside age, infertility history, ovarian response, fertilisation, embryo development and any embryos still available.
What is the difference between per-transfer and cumulative success rates?
Per-transfer success is live birth after one embryo transfer. Cumulative success is live birth from all fresh and frozen transfers of one retrieval (a complete cycle), or across several complete cycles.
How many IVF cycles should a couple realistically attempt?
There is no single number that is right for everyone. Registry studies report outcomes over as many as six cycles, but that is an observation window, not a recommendation. The decision should balance the updated medical prognosis with the physical, emotional, practical and financial burden.
Why do published cumulative rates vary between “optimistic” and “conservative” figures?
Optimistic figures assume that patients who stopped had the same chance of live birth as those who continued. Conservative figures assume that those patients would have had no later live birth. Neither assumption perfectly describes every person who stops treatment.
Sources
- Smith ADAC, Tilling K, Nelson SM, Lawlor DA. Live-Birth Rate Associated With Repeat In Vitro Fertilization Treatment Cycles. JAMA. 2015;314(24):2654-2662. doi:10.1001/jama.2015.17296.
- De Neubourg D, Bogaerts K, Anagnostou E, et al. Evolution of cumulative live birth and dropout rates over six complete IVF/ICSI cycles: a large prospective cohort study. Reproductive BioMedicine Online. 2021. doi:10.1016/j.rbmo.2021.01.005.
- McLernon DJ, Steyerberg EW, te Velde ER, Lee AJ, Bhattacharya S. Predicting the chances of a live birth after one or more complete cycles of in vitro fertilisation: population based study of linked cycle data from 113 873 women. BMJ. 2016;355:i5735. doi:10.1136/bmj.i5735.
- Malizia BA, Hacker MR, Penzias AS. Cumulative live-birth rates after in vitro fertilization. New England Journal of Medicine. 2009;360(3):236-243. doi:10.1056/NEJMoa0803072.
Add as a Preferred Source on Google
You can add draksoyivf.com as one of your preferred health information sources on Google.
The content has been created by Dr. Senai Aksoy and medically approved.