PCOS IUI Success Rate: Per-Cycle vs. Cumulative Numbers

What Is the IUI Success Rate for PCOS?

Twenty-four percent of first intrauterine insemination (IUI) cycles produced a clinical pregnancy in a cohort of 1,086 women with PCOS treated at a Shanghai teaching hospital between 2007 and 2021 — the largest PCOS-specific IUI dataset published to date, covering 1,868 completed cycles. That 24.13% first-cycle rate answers “what is my chance this cycle,” which is a genuinely different question from “what is my chance if I keep going,” covered separately below. Search results routinely blur the two into a single number, and that conflation is the reason this page exists.

IUI places washed, concentrated sperm directly into the uterus around the time of ovulation, usually alongside a medication to trigger that ovulation in the first place. It sits between oral ovulation-induction drugs and IVF on the PCOS fertility pathway — a step this site has not put a PCOS-specific number on until this page. The women in the cohort above averaged 33 years old, had already been diagnosed with PCOS by Rotterdam criteria, and underwent ovarian stimulation with letrozole plus a low dose of injectable gonadotropin before each insemination.

Every insemination in the cohort above was timed around a monitored ovulation, usually confirmed by ultrasound tracking of follicle growth rather than left to a home ovulation-predictor kit — the kits that are notoriously unreliable in PCOS specifically, because they detect a hormone that can run persistently elevated regardless of whether ovulation is actually happening. That monitoring detail matters for reading the success rates honestly: they describe cycles where a clinic confirmed the timing was right, not cycles where a couple guessed.

You may see PCOS written as polyendocrine metabolic ovarian syndrome (PMOS), after a May 2026 global consensus of more than 50 organisations renamed it. Every figure on this page holds under either name — only the label changed. This article uses PCOS, since that is still the term most readers search.

Per-Cycle vs. Cumulative: Why the Numbers Don’t Match Between Sites

By the fourth completed IUI cycle, cumulative clinical pregnancy in the same 1,086-woman cohort reached 39.14%, and cumulative live birth reached 30.95% — nearly identical to the cohort’s overall rate across every cycle any patient attempted (38.59% clinical pregnancy, 31.03% live birth), because roughly 98% of all pregnancies in the cohort occurred within the first three cycles.

The per-cycle rate does not stay flat as attempts continue, either. It was highest in the first cycle — 24.13% clinical pregnancy, 19.64% live birth — then fell over the next two to three cycles and settled near 22.50% clinical pregnancy and roughly 18% live birth per cycle from the fourth attempt onward. That is a real decline, not statistical noise: later cycles in this cohort were somewhat less likely to succeed than the first one, even though the cumulative number kept climbing simply because more attempts were being counted.

Read plainly: a single IUI cycle in this PCOS cohort carried roughly a 1-in-4 chance of a clinical pregnancy. A full course of three to four cycles raised the odds of at least one pregnancy to roughly 2-in-5 — because the chances from separate attempts compound, not because a fourth cycle works better than a first one. Neither number is wrong; they answer different questions, and a single figure lifted out of context answers neither one honestly.

This is also the number most likely to be quoted selectively. A cumulative rate always looks more favorable than the per-cycle rate it is built from, which is exactly why it shows up more often in marketing copy for fertility clinics than the harder, more sobering per-cycle number does. Reading both side by side, as Table 1 does, is the only way to see the full shape of the data rather than whichever half of it reads best.

Does Adding IUI Actually Beat Timed Intercourse in PCOS?

IUI raised the clinical pregnancy rate to 48.2%, more than four times the 11.0% rate on timed intercourse, in one PCOS-specific retrospective study of 147 clomiphene-stimulated cycles — and made no statistically significant difference against intercourse at all in a second, 666-woman randomized trial. Both are real findings from real studies. They disagree because they were designed differently, and the disagreement itself is worth understanding rather than picking whichever number is more convenient.

The first study compared 56 IUI cycles against 91 timed-intercourse cycles in women with PCOS undergoing clomiphene-stimulated ovulation induction at a single Turkish hospital. Patients chose which procedure to have rather than being randomly assigned, though the two groups were statistically similar in age, BMI, hormone levels, semen parameters, and how often they had intercourse. Clinical pregnancy rates were 48.2% with IUI against 11.0% with timed intercourse (p < 0.001) — a large, striking gap.

The second study is a randomized, two-by-two factorial trial run across 48 Dutch hospitals, enrolling 666 women with normogonadotropic anovulation — the broader diagnostic category PCOS falls under, though the trial did not require a formal Rotterdam PCOS diagnosis to enroll — who had not conceived after six ovulatory cycles of clomifene. Women were randomly assigned to gonadotrophins or clomifene, and separately to IUI or plain intercourse. Adding IUI produced a live birth in 49% of women against 43% with intercourse alone — a relative risk of 1.14 (95% CI 0.97–1.35) that did not reach statistical significance. Multiple pregnancy rates were low and did not differ between any of the groups.

Does It Matter How Many Ovulation-Induction Cycles Failed Before Starting IUI?

No — clinical pregnancy rates were statistically indistinguishable whether a woman had zero, one to two, or three or more failed oral ovulation-induction cycles before starting IUI, at 21.14%, 21.95%, and 23.64% respectively, in the 1,086-woman cohort above (p = 0.507). Live birth rates followed the same flat pattern: 16.64%, 18.06%, and 18.68% across the same three groups (p = 0.627).

That matters for anyone arriving at IUI after several rounds of letrozole or clomiphene that did not lead to a pregnancy. A history of prior ovulation-induction failures, on its own, was not associated with a lower ceiling once IUI started in this cohort — the drug not working is not the same signal as IUI being less likely to work for the same person.

How Many IUI Cycles Count as a Fair Trial?

About 98% of the pregnancies in the 1,086-woman cohort above occurred within the first three IUI cycles, which is the pattern the study’s own authors point to when discussing how many attempts are worth completing before outcomes plateau. That is a description of what happened in this dataset, not a rule for any individual to apply to their own treatment on their own.

What that plateau means for any one person’s decision to continue IUI or move toward IVF is exactly the kind of judgment call a fertility specialist makes using the full clinical picture — age, ovarian reserve, how a specific cycle responded to stimulation, and cost and access considerations this page cannot see. The IUI-versus-IVF sequencing decision covered here walks through the guideline-recognized factors that go into that conversation. This page reports where the plateau falls in the published data; it is not a substitute for that conversation.

Who Does IUI Not Help?

IUI cannot succeed against a blocked fallopian tube or a severe sperm problem, which is why the 1,086-woman cohort above excluded any couple with bilateral tubal obstruction or severe oligospermia, asthenospermia, or teratozoospermia before counting a single outcome. The procedure works by shortening the distance sperm has to travel around the time of ovulation; it does nothing to open a blocked tube and cannot compensate for too few or too immobile sperm to reach an egg at all. If either applies, IUI is not the right tool regardless of how many cycles are attempted.

The cohort also enrolled only women under 40, and required a post-preparation sperm sample above a stated quality threshold before a cycle counted as eligible. That is a pattern that recurs across fertility research generally: the letrozole trial that produced this site’s oral-induction success numbers enrolled only women with a confirmed patent fallopian tube and a partner with a sperm concentration of at least 14 million per millilitre. The percentages in this article describe outcomes once a baseline fertility work-up has already ruled out those bigger structural problems — not the general population of everyone who has ever received a PCOS diagnosis.

None of the studies above broke results down further by PCOS phenotype. That granularity does not yet exist for IUI specifically, unlike for oral ovulation induction, where insulin-resistant and lean phenotypes are already known to respond somewhat differently. That is a real gap in the evidence, worth naming rather than papering over with a single number that may not describe every phenotype equally.

IUI cycles are also usually paired with a stimulation medication to control the timing and number of mature follicles, and how that stimulation is managed changes the chance of a multiple pregnancy — a separate safety question covered in full on the gonadotropin ovulation-induction page, since it applies whether or not IUI is added on top.

IUI is also, deliberately, a less invasive and less expensive step than IVF — that is the whole reason it sits where it does on the treatment ladder, offering a lower-intensity option before committing to egg retrieval. That positioning is a description of how fertility medicine is organized, not a recommendation about which option is right for any individual reading this; cost, access, and time already spent trying are all real factors a specialist weighs alongside the success-rate numbers above.

Where Does IUI Sit in the PCOS Fertility Pathway?

The 2023 international PCOS guideline frames IUI as one option among several once oral ovulation-induction alone has not led to a pregnancy after a monitored trial — not a mandatory single step everyone passes through in a fixed order, and not a decision this page can make for any individual reader. The referral timelines that lead to this conversation are covered in full separately, and apply before any of the numbers on this page become relevant.

For the broader question of whether PCOS blocks pregnancy at all, the actual PCOS conception rates by cohort cover that separately — most women with PCOS conceive, with or without IUI specifically, and this page’s numbers describe one step inside that larger picture. IUI itself is part of the wider PCOS fertility guide this site maintains, not an isolated procedure with its own separate logic.