Quick answer. The most meaningful measure of IVF success is the live-birth rate per cycle (a baby taken home), not just a positive pregnancy test. The single biggest driver is the woman’s age: live-birth rates per cycle are roughly 40-50% for women under 35 and fall steadily after about 35, dropping sharply after 40 to around 10% or less. Because a single cycle is unlikely to succeed for many patients, cumulative success across 2-3 cycles is considerably higher than any single-cycle figure. These are population averages only; your individual prognosis depends on egg and embryo quality, ovarian reserve, sperm factors, the cause of infertility and other variables, so a personalised specialist assessment is essential.
If you are looking into IVF in Singapore, success-rate figures can be confusing and easy to misread. A clinic quoting “50%” and one quoting “25%” may be measuring completely different things, or simply treating different patients. This guide explains how IVF success is actually measured, why the woman’s age matters more than almost anything else, what other factors move the odds, and why naive clinic-versus-clinic comparisons can mislead.
At a glance
| Woman's age | Approx live-birth rate per cycle | Notes |
|---|---|---|
| Under 35 | ~40-50% | Best prognosis; egg quality and quantity generally highest |
| 35-37 | ~30-36% | Begins a noticeable decline; still a good chance, especially across cycles |
| 38-40 | ~20-25% | Falling steadily as egg quality declines and miscarriage risk rises |
| 41-42 | ~10-15% | Markedly lower; more cycles often needed for a reasonable cumulative chance |
| 43-44 | ~5% or lower | Low with own eggs; donor eggs are sometimes discussed |
| 45 and above | Very low / near zero | Live births from a woman's own eggs are rare; specialist counselling essential |
How IVF success is measured (and why it matters)
IVF outcomes can be reported in several ways, and the denominator changes the headline number dramatically. The three most common framings are:
- Per cycle started (or per egg retrieval): the chance of a live birth from one stimulation cycle, counting everyone who started even if no eggs or embryos were obtained. This is the most honest, real-world figure.
- Per embryo transfer: the chance of a live birth each time an embryo is placed in the womb. This number is usually higher because it excludes cycles that never reached transfer.
- Cumulative live-birth rate: the chance of at least one live birth across several cycles, often including frozen embryos from one egg collection. This best answers the question patients really care about: “What is my overall chance of taking home a baby?”
Two further distinctions matter. First, insist on live birth rather than “pregnancy rate” or “positive test” – many early pregnancies do not progress, so pregnancy rates overstate the chance of a baby. Second, check whether a figure refers to a woman’s own eggs or donor eggs; donor-egg success rates are high and relatively flat across recipient age, so mixing them in inflates the average.
Age is the single biggest driver
A woman’s age at the time her eggs are collected is by far the strongest predictor of IVF success, because egg quantity and (especially) egg quality decline with age. As eggs age, a larger proportion carry chromosomal abnormalities (aneuploidy), which lowers fertilisation, implantation and healthy-pregnancy rates and raises miscarriage risk.
The decline is gradual through the early 30s, becomes more noticeable after about 35, and falls sharply after 40. In US national data (CDC, 2022), the live-birth rate per egg retrieval using a woman’s own eggs was about 49.7% under 35, 36.3% at 35-37, 23.1% at 38-40, and lower still beyond that. UK data (HFEA) shows a similar pattern. Singapore’s Ministry of Health states plainly that the chance of conception through ART decreases with age, with the success rate being significantly lower after 40 – the clinical rationale behind the public co-funding age cap.
The male partner’s age has a smaller but real effect on sperm quality and DNA integrity, though it is far less decisive than the woman’s age.
What else affects your odds
Beyond age, several factors shift the probability of success for an individual:
- Ovarian reserve: measured by AMH (anti-Mullerian hormone) and antral follicle count. These predict how many eggs you are likely to produce per cycle – the number of eggs/embryos available more than the quality of any single embryo, where age remains the better guide.
- Egg and embryo quality: the proportion of eggs that fertilise and develop into healthy blastocysts. Strongly age-linked.
- Sperm factors: count, motility, morphology and DNA fragmentation. Severe male-factor infertility is often addressed with ICSI.
- Cause and duration of infertility: some causes (e.g. tubal blockage with normal eggs and sperm) carry a better prognosis than others (such as poor ovarian reserve or long-standing unexplained infertility).
- Lifestyle: a high or very low BMI and smoking both reduce success rates; smoking in particular is consistently linked to lower live-birth rates.
- Number of cycles: the cumulative chance of success rises with each additional cycle attempted.
- Laboratory and treatment approaches: blastocyst transfer (growing embryos to day 5-6) and, in selected patients, PGT-A can improve live-birth rates per transfer and reduce miscarriage by prioritising chromosomally normal embryos. PGT-A is not beneficial for everyone, and evidence on whether it improves the cumulative chance of a baby is mixed, so it should be discussed case by case.
Cumulative success: why one cycle isn't the whole story
For many patients, a single IVF cycle is more likely to fail than succeed – so judging IVF on one attempt is misleading. The cumulative live-birth rate, which counts the chance of a baby across multiple cycles (and across frozen embryos banked from a single egg collection), is substantially higher than any single-cycle figure. Studies consistently show meaningful gains across the first two to three cycles, especially in younger women with reasonable ovarian reserve.
This is also why clinics increasingly aim to make the most of each egg collection through blastocyst culture and frozen-embryo transfers: several transfers may come from one stimulation. The practical takeaway is to plan, emotionally and financially, for the possibility of more than one cycle, and to discuss with your specialist a realistic estimate of your cumulative odds given your age and test results.
Why comparing clinic 'league tables' can mislead
It is tempting to pick the clinic with the highest advertised success rate, but raw clinic numbers are not directly comparable. The main reason is patient mix (case mix): a clinic that treats mostly younger women, or that declines very poor-prognosis cases, will post higher headline rates than a clinic that accepts complex or older patients – without necessarily being “better.”
Other reasons numbers differ between clinics include: whether figures are per cycle versus per transfer; whether donor-egg cycles are bundled in; how frozen-transfer success is counted; and the size of the sample (small clinics show large year-to-year swings). When reviewing any clinic’s statistics, ask which denominator is used, whether the figures are broken down by age band, whether they report live births, and whether they exclude donor eggs. A reputable centre will explain its numbers transparently and put your own prognosis in context rather than quoting a single flattering headline.
IVF in Singapore: the local context
In Singapore, the three public assisted-reproduction centres are KK Women’s and Children’s Hospital (KKH), National University Hospital (NUH) and Singapore General Hospital (SGH), alongside several private fertility centres. Singapore Citizen couples who begin treatment before age 40 at a public centre are eligible for government co-funding (up to 75% of treatment cost, subject to caps per cycle), reflecting the policy goal of encouraging earlier treatment when success rates are higher.
Locally reported figures are consistent with international patterns. SGH’s centre has cited overall pregnancy rates of roughly 40% for fresh cycles and around 50% for frozen cycles, while noting that live-birth rates decline drastically for women above 40, with effectively no recorded pregnancies from a woman’s own eggs at 45 and above. Because definitions and patient populations differ, treat any single quoted percentage as a rough guide and ask your specialist for an estimate tailored to you.
Related guides
- Best Fertility Clinics in Singapore — our editorial shortlist
- fertility clinics directory
- IVF cost in Singapore (2026)
- Egg freezing in Singapore: law & cost
- When to see a fertility specialist
Sources
- HFEA – Fertility treatment: key facts and statistics (UK regulator)
- CDC – ART Surveillance and National Summary (US success rates by age)
- Singapore Ministry of Health – Age cap for IVF co-funding
- Singapore General Hospital – Family and fertility: Is IVF the magic bullet?
- NEJM – Live Birth with or without PGT for Aneuploidy (randomised trial)
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