Why Doctors Suggest One IVF Cycle First: Understanding an Unexpected Stimulation Result

A familiar conversation takes place in fertility clinics. A woman in her early thirties brings her AMH result, hormone tests, ultrasound report and her partner's semen analysis to a first IVF consultation. After reviewing them, the doctor says: “Things look reasonable. Let's start with one cycle and see how you respond.”

“See how I respond?” she wonders. With so much money, medication and effort involved, why is the answer still uncertain? Two months later, five oocytes have been retrieved and one blastocyst has developed. She has more questions.

These are reasonable questions. A first IVF cycle is a little like walking an unfamiliar mountain route: the tests provide a map and the clinician acts as a guide. The map describes the terrain, but some conditions become apparent only during the journey.

What can be predicted before stimulation?

The initial assessment usually considers age, anti-Müllerian hormone (AMH), antral follicle count (AFC: the small follicles visible on an early-cycle ultrasound), body weight and medical history. AMH and AFC are among the most useful measures of ovarian reserve.

An individual-patient-data analysis of 28 studies involving 5,705 women reported an area under the receiver operating characteristic curve (AUC) of 0.78 for AMH and 0.76 for AFC in predicting poor ovarian response.[1] AUC measures discrimination between poor and non-poor responders: 0.5 is close to random discrimination, and 1.0 represents perfect discrimination in the sample. An AUC of 0.78 does not mean “78% accurate,” and it cannot be converted into an individual's exact egg count. In the same analysis, these tests did not add information beyond age for predicting ongoing pregnancy.[1]

The patient information accompanying ESHRE's 2025 ovarian stimulation guideline similarly explains that reserve tests predict egg quantity rather than whether a pregnancy will occur.[2]

Other features emerge during treatment:

• Sensitivity to follicle-stimulating hormone (FSH): follicles may grow readily or respond slowly to the same dose.
• Whether follicles grow together or become uneven in size before the final maturation trigger.
• The proportion of retrieved oocytes that are mature.
• Whether the oocytes and sperm fertilize successfully.
• Whether fertilized oocytes develop into blastocysts.

“Let's try one cycle” therefore describes a treatment that also supplies information unavailable from the initial tests. This is an acknowledged limitation of prediction in reproductive medicine.

“Exploratory cycle” is a metaphor used in this article, not a formal medical diagnosis or the name of a standardized protocol.

Response varies between people and between cycles

The way poor response is classified illustrates why previous treatment matters. The 2011 ESHRE Bologna criteria include a previous conventional stimulation cycle yielding no more than three oocytes as one criterion.[3] The POSEIDON framework proposed in 2016 includes two groups with an unexpectedly low or suboptimal yield despite adequate reserve markers: AMH ≥1.2 ng/mL and/or AFC ≥5, followed by fewer than four or four to nine oocytes after conventional stimulation.[4] Classification in these groups requires the result of an actual previous cycle.

A multicentre series of more than 13,000 ART patients, discussed in a POSEIDON editorial, found that approximately 43% met low-prognosis criteria; many belonged to groups 1 and 2, whose reserve markers appeared adequate.[5]

Differences in sensitivity to FSH, potentially involving receptor-related genetic variation, are one proposed explanation for an unexpected response. This remains a mechanistic hypothesis; routine testing cannot reliably predict an individual's response from these differences.[7]

A multicentre retrospective study across the United States, Europe and Asia compared 801 pairs of consecutive cycles within six months. Each pair used the same protocol, gonadotropin type and initial and daily doses; all were freeze-all cycles.[6]

• Half the patients had a difference in retrieved oocyte numbers exceeding one-third. The median difference in women aged 40 or older was 44.4%.[6]
• Overall, 381 of 801 patients (47.57%) moved between response categories, defined in the final journal report as 1–3, 4–9, 10–14 and ≥15 oocytes.[6]

The variation occurred despite unchanged treatment conditions. One low yield does not by itself establish that a protocol was wrong, and a higher yield does not guarantee the same result next time.

How the first cycle informs the next

A Belgian retrospective study followed 160 women under 40 with normal reserve markers who retrieved four to nine oocytes after 150 IU daily in their first cycle. Approximately two-thirds received a higher dose in the second cycle. Overall median yield rose from six to nine oocytes; the average increase was 3.2 in the higher-dose group and 2.1 in the unchanged-dose group.[7]

After adjustment for other factors, an increase of approximately 50 IU in starting dose was associated with about one additional oocyte.[7] The improvement among women whose dose stayed the same is an important part of interpreting the result.

Why not start with the highest dose?

If a low yield is a concern, why not use a large dose immediately? The Dutch OPTIMIST programme investigated reserve-based dosing in 1,515 women starting IVF, comparing individualized doses with a standard 150 IU daily strategy.[8,9,10]

• Among predicted low responders with AFC <11, 225 or 450 IU daily produced a cumulative live-birth rate of 42.4%, compared with 44.8% at 150 IU; the higher-dose strategy did not improve live birth (RR 0.95, 95% CI 0.78–1.15).[8]
• Among predicted high responders with AFC >15, 100 IU versus 150 IU gave cumulative live-birth rates of 66.3% and 69.5% (P=0.42). Any-grade ovarian hyperstimulation syndrome (OHSS) occurred in 5.2% versus 11.8%; severe OHSS was 1.3% versus 1.1%.[9]
• For the overall strategy, live-birth rates were 56.3% with individualized dosing and 58.2% with standard dosing, a difference of −1.9 percentage points (95% CI −6 to 2). Individualized dosing cost approximately €275 more per woman.[10]

ESHRE's patient information explains that a higher FSH dose does not improve egg quality and describes a usual target of around 8–15 oocytes.[2] An analysis of 400,135 historical UK fresh IVF cycles found that live-birth rates increased up to approximately 15 oocytes, plateaued between 15 and 20, and declined above 20.[11] These are fresh-cycle observations, not a universal target for every patient or a measure of cumulative outcomes after all frozen transfers.

A standard starting dose can therefore be a considered choice. More medication adds exposure and can increase overstimulation risk without changing ovarian reserve itself.

Some answers emerge only in the laboratory

Retrieval is only part of the process. Fertilization and development to a blastocyst are observed afterwards.

A Chinese single-centre retrospective study of 19,539 first conventional IVF cycles reported total fertilization failure in 7.5% of cycles, rising to 21% among poor responders. Semen parameters alone had an AUC of approximately 0.57–0.58 for predicting this outcome.[12] The first fertilization result can therefore inform a discussion of whether intracytoplasmic sperm injection (ICSI) is appropriate in a later cycle.

Medication can influence part of the egg yield, while age is strongly related to oocyte competence. In the UK fresh-cycle analysis, the predicted live-birth rates at a yield of 15 oocytes were approximately 40% at ages 18–34, 36% at 35–37, 27% at 38–39 and 16% at 40 or older.[11]

A protocol can affect how many oocytes are retrieved, but it cannot reverse the age-related biology of each oocyte. In the mountain-route analogy, an experienced guide still has to work with the terrain.

A first unsuccessful cycle is common

A UK registry study followed 156,947 women through 257,398 stimulation cycles from 2003 to 2010. Live birth occurred in 29.5% after the first cycle. The prognosis-adjusted cumulative estimate after six cycles was 65.3%; among women under 40, the corresponding figures were 32.3% and 68.4%, and at ages 40–42 they were 12.3% and 31.5%.[13]

The cumulative estimates depend on assumptions about women who stopped treatment. Embryo culture and freezing have also changed since this historical cohort. These figures illustrate how outcomes accumulate across repeated treatment; they do not predict a particular person's outcome or prescribe six cycles for everyone.

Biological uncertainty and the care you can review

An uncertain outcome does not remove the need for careful assessment, monitoring and explanation.

Findings that may reflect biological limits or variation

• Age and ovarian reserve.[11]
• An unexpectedly low response despite adequate reserve markers.[4,5]
• Natural variation between cycles using the same treatment.[6]
• Unexpected failure of conventional fertilization, including when routine semen results appear normal.[12]

Elements of care to discuss

• Was reserve assessed before stimulation, using AMH or AFC?[2]
• Did the starting dose take account of age, body weight, reserve and OHSS risk?[2]
• Was ultrasound monitoring planned, with hormone testing when clinically indicated, and were medication and trigger timing assessed against follicular growth?
• Were retrieved, mature and fertilized oocyte numbers and blastocyst numbers explained, rather than the outcome being reduced to “no embryos developed”?
• Was there a cycle review explaining what differed from expectations and what might change next time?

Even when these steps have been followed, a disappointing outcome may require a closer review of ovarian response, gametes and laboratory records. A single result is insufficient to judge a clinician's competence. If assessment, monitoring or explanation was missing, it is reasonable to request the records, seek an explanation or obtain a second opinion.

Questions for the post-cycle consultation

The first cycle becomes more useful when its observations inform the next decision. Review egg yield, maturity, fertilization and blastocyst formation separately.

Five questions can help structure the conversation:

• Was the egg yield above or below the pre-treatment estimate?
• What proportion of oocytes were mature, and does trigger timing need review?
• What was the fertilization rate, and should ICSI be discussed?
• How did blastocyst formation compare with expectations for my age?
• What protocol, dose or strategy would change next time, and why?

What “one cycle first” means

The phrase acknowledges that medicine cannot fully predict how an individual ovary will respond before treatment begins. The first cycle should be followed by a meaningful review of what happened and what it means for subsequent decisions.

After an unexpected result, the useful discussion is specific: what did we observe, which stage differed from expectations, and what supports the proposed next step? The tests, monitoring and cycle review remain part of good care throughout.

Evidence table

The manuscript's evidence search ran through 17 October 2026 and was not a registered systematic review. On 25 October, the website checked the final journal abstract for reference [6] and adopted 801 cycle pairs, 47.57% category change and the journal's category thresholds. An earlier conference abstract reported 802 patients and 49.3%. Reference [2] links to the guideline; its ESHRE page also provides the patient version.

Medical and image information

This article provides medical education based on published literature. It does not replace an individual consultation or prescribe a treatment protocol. The opening consultation is a composite illustration of common questions, not an account of an identifiable patient. Protocols, doses and subsequent changes require individual clinical assessment.

The evidence table identifies study designs and populations. The care-review checklist and cycle-review graphic are the article's own synthesis, not formal society recommendations. The website retains the manuscript's five infographics and uses concept illustrations supplied by the owner. Illustrations do not depict actual patients, clinical events or medical imaging.