Yes — IVF babies are born early more often than naturally conceived babies, but the gap is smaller than most people fear and largely preventable. A classic meta-analysis of more than 12,000 IVF singleton pregnancies found about 1.9 times the risk of birth before 37 weeks (odds ratio 1.93) compared with naturally conceived singletons matched for maternal age.
The single biggest driver of early delivery in IVF is not the treatment itself — it is twin or triplet pregnancy, which occurs far more often when multiple embryos are transferred. Elective single embryo transfer (eSET) dramatically reduces this risk. Data here comes from the peer-reviewed literature (McDonald et al., 2005), the CDC National ART Surveillance System, and public ASRM guidance, compiled by the ProIVF Medical Editorial Team and reviewed by the ProIVF Medical Advisory Board.
Are IVF Babies Born Early? The Short Version
Most IVF babies — about 85–90% of IVF singletons — are born full term at 37 weeks or later. The elevated preterm risk is real but modest, and it reflects the mothers who need IVF (older average age, more high blood pressure or PCOS) as much as the treatment itself.
| Question | What the evidence says |
|---|---|
| Do IVF babies come early? | On average, slightly — but most IVF babies are born full term |
| How much earlier? | Singleton IVF: ~1.9x the risk of birth before 37 weeks vs natural conception |
| Why? | Mostly multiple pregnancy, plus maternal age and the underlying infertility diagnosis |
| Can you reduce the risk? | Yes — single embryo transfer and standard prenatal care make the biggest difference |
What the Data Shows: IVF Singleton Preterm Birth Rates
The most frequently cited evidence is McDonald et al., Journal of Obstetrics and Gynaecology Canada, 2005, a systematic review and meta-analysis comparing IVF singletons with naturally conceived singletons matched for maternal age. An odds ratio (OR) compares how often an outcome occurs in two groups: above 1 means higher risk with IVF, below 1 means lower — so the preterm OR of 1.93 means IVF singletons have roughly 1.9 times the odds of delivery before 37 weeks.
| Outcome (singleton pregnancies) | Odds ratio (IVF vs natural) | Interpretation |
|---|---|---|
| Preterm birth before 37 weeks | 1.93 | Roughly double the risk — about 10–13% of IVF singletons vs ~7–8% naturally |
| Preterm birth before 33 weeks | 2.99 | About triple the risk — the rarer, more serious early births |
| Perinatal mortality | 2.40 | Higher, driven largely by prematurity |
| Very low birth weight (<1,500 g) | 3.78 | Higher, closely tied to early preterm birth |
| Small for gestational age | 1.59 | Higher — babies born smaller than expected |
| Congenital malformations | 1.41 | Slightly higher; absolute risk remains low (~2–4%) |
Two caveats matter. This 2005 study reflects older IVF practice, when multiple embryo transfers were common and laboratory techniques were less advanced, and it adjusted for maternal age but not all health differences. More recent cohort studies show improving outcomes as single embryo transfer became standard, and the CDC’s annual ART surveillance report now tracks singleton live birth rates and multiple birth rates per clinic. Our IVF success rates by age guide and twin HCG levels guide cover related questions.
Why Do IVF Pregnancies Deliver Earlier?
The elevated preterm risk is not a simple “IVF causes prematurity” story — four factors combine.
1. Multiple Pregnancy — The Biggest Factor
When two embryos are transferred and both implant, the result is a twin pregnancy — and twins are born before 37 weeks in roughly 50–60% of cases, regardless of how they were conceived. Historically, about one-third of US IVF births were multiples according to CDC ART surveillance data; that share is now falling as single embryo transfer becomes standard, but multiples remain the dominant driver of early delivery in IVF.
2. Maternal Age and Health
IVF patients are on average older and more likely to have uterine fibroids, thyroid disorders, or prior pregnancy complications, each of which raises preterm risk independently. Matching for age in studies helps but does not remove this effect.
3. The Underlying Infertility Diagnosis
The reason a woman needs IVF can itself be tied to placental or uterine factors linked to earlier delivery. Endometriosis, PCOS, uterine anomalies, and repeated pregnancy loss are common examples.
4. Placental Differences
Some studies find slightly higher rates of placenta previa, placental abruption, and hypertensive disorders in IVF pregnancies, and these often lead to medically indicated early delivery.
For a full review of the risks that matter in IVF, including OHSS and ectopic pregnancy, see our IVF risks guide.
Can Single Embryo Transfer Reduce Preterm Birth?
Yes — transferring one embryo at a time is the single most effective way to reduce the chance of an early baby. The comparison makes the scale clear:
- Singletons conceived through IVF: ~10–13% preterm rate
- Twins (any conception): ~50–60% preterm rate
- Triplets: ~90%+ preterm rate
Elective single embryo transfer (eSET) offers live birth rates per cycle comparable to transferring two embryos in many age groups, while nearly eliminating the twin risk. PGT (preimplantation genetic testing) screens embryos for chromosome number before transfer, and with a PGT-confirmed euploid embryo eSET’s success holds across more age groups.
“Elective single embryo transfer is recommended for patients under the age of 35 with a favorable prognosis.” — American Society for Reproductive Medicine, ASRM, Guidance on the Number of Embryos Transferred, 2022
If your clinic recommends transferring two embryos, ask why, and ask for the clinic’s own multiple-birth rate — that number is published in the CDC data. Our chances of twins with IVF guide explains the trade-offs in detail.
What Does “Coming Early” Mean in Practice?
For most IVF babies, “early” means 36–37 weeks — a short stay in the well-baby nursery, or none at all. The NICU (neonatal intensive care unit) provides specialized care for newborns who need extra monitoring.
| Gestational age | Typical experience |
|---|---|
| 37–38 weeks (early term) | Usually healthy; occasionally brief observation |
| 34–36 weeks (late preterm) | Short NICU stay for feeding and temperature support in some cases |
| Before 34 weeks | NICU stay likely; outcomes depend on gestation and care |
| Before 28 weeks | Serious prematurity; rare in IVF singletons |
Modern neonatal care is excellent, and long-term outcomes for late-preterm and most moderately preterm babies are good. Studies of IVF children find that, after accounting for prematurity and multiple birth, their health and development match naturally conceived children — our guide to what an IVF baby is and how they develop reviews the evidence.
Patient Stories: Three Different Paths
The following patient stories are shared with consent. Names and identifying details have been changed to protect privacy.
Case 1: Rachel, 34 — Two Embryos, Twins at 35 Weeks
Rachel, 34, delivered twins at 35 weeks and 2 days after a two-embryo transfer. Both spent 12 days in the NICU and are healthy toddlers now.
Rachel’s clinic transferred two embryos in her second cycle, and both implanted. “We were thrilled, and terrified. The doctor told us twins almost always come early,” she said. Her twins were born at 35 weeks and 2 days, weighing 4 lb 9 oz and 4 lb 13 oz, and spent 12 days in the NICU for feeding support; both are healthy toddlers now. Total cost for the cycle: $19,000 at a clinic in Ohio. “If I could go back, I’d ask more questions about single embryo transfer,” she said.
Case 2: Amara, 38 — Single Embryo, Full Term at 39 Weeks
Amara, 38, delivered full term at 39 weeks and 1 day after a single embryo transfer, with no NICU stay.
Amara chose a single embryo transfer with a PGT-tested embryo. “My doctor was very clear: one embryo at a time, because the baby’s health matters more than speed,” she said. Her daughter was born at 39 weeks and 1 day, weighing 7 lb 6 oz, with no NICU stay. Total cost: $16,500 at a clinic in Texas.
Case 3: Sophie, 32 — Single Embryo, Mild Early Arrival at 36 Weeks
Sophie, 32, had a mild early arrival at 36 weeks and 5 days after a single embryo transfer, and her son went home healthy.
Sophie’s son arrived at 36 weeks and 5 days after a smooth pregnancy. “He was born 8 days before my induction date — the doctors said he was ready,” she recalled. He weighed 5 lb 14 oz and spent 3 nights in the well-baby nursery for temperature checks, then went home healthy. Total cost: $15,200 at a clinic in California.
FAQ
Q: Do IVF babies come early?
On average yes, but most do not. IVF singleton pregnancies carry about 1.9 times the risk of birth before 37 weeks compared with natural conception, and roughly 85–90% of IVF singletons are born full term.
Q: Why are IVF babies born early?
The biggest reason is multiple pregnancy — twins or triplets from transferring multiple embryos — and about 50–60% of twins arrive before 37 weeks. Maternal age, underlying infertility diagnoses, and slightly higher rates of placental and hypertensive conditions also contribute.
Q: Do IVF twins always come early?
Most twins — IVF or natural — are born before 37 weeks (roughly 50–60% of cases). Obstetric teams often plan twin delivery by 38 weeks because carrying twins longer raises risks for both babies, which is exactly why single embryo transfer is recommended: it nearly eliminates the twin risk.
Q: Does single embryo transfer reduce preterm birth?
Yes, substantially. Elective single embryo transfer (eSET) removes the twin risk — twins arrive early in 50–60% of pregnancies — which is the dominant cause of early delivery in IVF, and in good-prognosis patients eSET success rates are comparable to transferring two embryos.
Q: What is the preterm birth rate for IVF singletons?
About 10–13% of IVF singleton pregnancies deliver before 37 weeks, versus roughly 7–8% of naturally conceived singletons, based on the McDonald 2005 meta-analysis. Rates vary by maternal age, clinic, and whether a single embryo was transferred.
Q: If my IVF baby comes early, will they need the NICU?
It depends on gestational age. Babies born at 34–36 weeks often need only a short nursery or NICU stay measured in days, while babies born before 34 weeks are more likely to need longer NICU care.
Most late-preterm IVF babies go home healthy.
Q: Are IVF babies healthy long-term?
Yes. The 1.9x singleton preterm signal is just one of several factors your care team will monitor.
After accounting for prematurity and multiple birth, studies of IVF children find overall health and development comparable to naturally conceived children.
How to Plan Your IVF Journey
- Discuss embryo transfer count before your cycle starts. Ask your doctor for the clinic’s own singleton rate, multiple birth rate, and live birth rate — all three are published in CDC data — and ask whether single embryo transfer is right for you.
- If you are under 35 with a good-prognosis embryo, expect eSET to be the recommendation. It protects the baby without meaningfully lowering your per-cycle chance in most cases.
- Plan prenatal care with prematurity in mind. Choose a hospital with a good NICU, and talk to your OB about cervical length screening and blood-pressure monitoring.
- Budget for the possibility of early delivery. Even a short NICU stay can add to costs; most insurance covers it, but check your plan.
- Compare clinics on the outcomes that matter. The CDC’s ART success-rate data and the SART dashboards show singleton rates and multiple rates per clinic.
Browse vetted clinics in our hospital directory, or reach out through our contact page for help comparing your options.
This article was written by the ProIVF Medical Editorial Team and reviewed by the ProIVF Medical Advisory Board. It is based on publicly available data from the peer-reviewed literature, the CDC National ART Surveillance System, and ASRM guidance to provide objective, accurate information for patients.
Medical Disclaimer: This content is for informational purposes only and does not constitute medical advice. Always consult a licensed reproductive specialist and your obstetric care team for your individual situation.
Last updated: August 6, 2026.
