If you have just seen a positive test after IVF, the relief usually lasts about a minute before a harder question arrives: will this pregnancy last? Miscarriage after IVF happens in roughly 10–25% of clinical pregnancies, and the strongest driver of that risk is the age of the egg — not the IVF process itself. Once a heartbeat is seen on ultrasound, loss rates in IVF pregnancies are broadly similar to those in natural conception at the same age. This guide walks through the real numbers by age, fresh versus frozen transfer, and embryo genetic testing, so you can see where your own pregnancy sits. Updated 2026.
Does IVF itself raise the risk of miscarriage?
On paper, IVF pregnancies miscarry slightly more often than natural pregnancies — but most of that gap is explained by two things that are not the treatment itself. First, IVF patients are older on average, and age is the dominant miscarriage risk factor in every population studied. Second, IVF pregnancies are detected and monitored far earlier than natural ones. A natural pregnancy that ends at four weeks usually passes as a slightly late period and is never counted. An IVF pregnancy is confirmed by a blood test around 9–14 days after transfer, so losses that would be invisible in natural conception are recorded in IVF statistics. Researchers call this detection bias, and it inflates the IVF numbers mostly before a heartbeat is ever seen.
The pattern underneath the headline rates is more reassuring: once a fetal heartbeat is confirmed, IVF and natural-conception loss rates converge at the same age. You can explore that week-by-week pattern yourself with our miscarriage risk calculator, which shows how the odds change as each week passes.
Miscarriage rates after IVF by age
Age is the single strongest predictor of miscarriage after IVF, because the rate of chromosomal errors in eggs rises steeply from the mid-30s onward. The clearest age data comes from Magnus et al. (BMJ, 2019), who analysed over 400,000 pregnancies in Norway and found the following risk of miscarriage by maternal age:
- Ages 25–29: 9.7%
- Ages 30–34: 10.8%
- Ages 35–39: 16.7%
- Ages 40–44: 33.2%
These figures are from natural conception, but they are the right benchmark for IVF too: once a heartbeat is seen, IVF pregnancies at each age track close to these same numbers. Before a heartbeat, overall clinical miscarriage rates in IVF are commonly reported at around 10–25%, with the top of that range reflecting older patients and very early losses counted from the first blood test. Under 35, most clinics report rates toward the lower end; over 40, the rate climbs steeply, mirroring the BMJ curve.
Why age matters more than the treatment
Age matters because of aneuploidy — an embryo carrying the wrong number of chromosomes. Aneuploidy is the leading known cause of early miscarriage, accounting for roughly 50% of early pregnancy losses. The share of aneuploid eggs rises with maternal age, which is why the age curve bends upward so sharply after 35 and again after 40, in IVF and natural conception alike. Our companion guide breaks down miscarriage risk by age across the full age range, including donor-egg pregnancies.
Chemical pregnancy after IVF: the earliest kind of loss
A chemical pregnancy (also called a biochemical pregnancy) is a pregnancy that produces a positive hCG test but ends before anything can be seen on an ultrasound scan. After IVF, chemical pregnancies are commonly reported in roughly 10–20% of positive tests. A chemical pregnancy is not a "false" pregnancy or a faulty test — an embryo implanted and produced hCG, then stopped developing, most often because of a chromosomal error.
This is where detection bias hits hardest. In natural conception, most chemical pregnancies are never detected at all; the period simply arrives a few days late. After IVF, your clinic tests on a fixed day, so every one of them is seen and counted. That is a large part of why IVF loss statistics look worse at the very earliest stage. Because clinics monitor beta hCG closely in these first weeks, you can follow what your own numbers mean with our hCG level checker — rising hCG that roughly doubles every 48 hours in the earliest days is the pattern clinicians want to see.
Fresh vs frozen transfer: does freezing change the risk?
A frozen embryo transfer (FET) is a transfer of an embryo that was frozen after fertilisation and thawed for transfer in a later cycle, rather than transferred fresh in the same cycle as egg collection. On miscarriage, large registry analyses consistently find that frozen transfers have similar rates to fresh transfers — and in many patient groups, slightly lower. The difference is modest, not dramatic, and it varies by age and clinic population, so treat "frozen is a little kinder" as a tendency, not a guarantee.
Why frozen transfers can do slightly better
Two mechanisms are usually proposed. In a fresh cycle, the uterine lining has just been exposed to high stimulation hormone levels, which can make it slightly less receptive; a frozen cycle lets hormone levels return to normal first. Frozen cycles also allow clinics to avoid transferring into an environment affected by ovarian hyperstimulation risk. Neither factor changes the embryo's chromosomes, though — which is why the fresh-versus-frozen gap stays small next to the age effect. If your transfer was frozen, our FET due date calculator works out your key dates from transfer day and embryo age.
PGT-A and euploid embryos: the one lever that lowers risk
A euploid embryo is one with the correct number of chromosomes; PGT-A (preimplantation genetic testing for aneuploidy) is the biopsy test used during IVF to identify euploid embryos before transfer. Because aneuploidy causes roughly half of early miscarriages, screening it out flattens the age curve considerably: miscarriage after transfer of a euploid embryo is commonly reported at around 10% or lower across age groups, including for patients over 38, whose untested-embryo rates are far higher.
PGT-A is not a guarantee and is not recommended for everyone — it cannot detect every problem, and uterine, hormonal, and other factors still play a role. But if you transferred a tested euploid embryo, your age-based statistics from the table above overstate your personal risk; the euploid rate is the more relevant number for you.
After the heartbeat: when the odds turn in your favour
The 6–7 week scan is the milestone that changes the maths. Tong et al. (2008) followed pregnancies after fetal heart activity had been seen and found that the risk of subsequent loss fell steeply with each passing week — by 8 weeks, the remaining risk was around 1.5%. The same post-heartbeat pattern applies to IVF pregnancies: the anxious gap between a positive test and the first scan is statistically the riskiest window, and every week after a confirmed heartbeat lowers the odds further. Our guide to miscarriage odds after a heartbeat is seen walks through those week-by-week numbers, and miscarriage risk by week shows the full curve from week 4 onward.
Putting your own numbers together
No single statistic describes your pregnancy — your age, your embryo, and how far along you are all feed into the same picture. When you are ready, estimate your week-by-week odds using the age and week figures from this guide, and work out your IVF due date to anchor the timeline. Population numbers are a map, not a verdict: many pregnancies with worrying statistics end in healthy babies, and your own clinic, which knows your history and your embryos, is always the better guide. After everything it took to get this far, it is completely normal to check the numbers often — and just as normal to put the phone down and take it one scan at a time.