Single vs Double Embryo Transfer in IVF

Reading time: about 8 minutes. This article is educational and does not replace an individual consultation.

When you are going through IVF, the instinct is understandable: if one embryo gives you a chance of a baby, surely putting two back doubles it? It is one of the most common questions couples ask — and one of the most important to answer carefully. The honest, evidence-based answer is more nuanced than “more is better.” For most people with a good prognosis, transferring a single embryo is the safer route to the same goal: one healthy baby. This article explains why, what the guidelines actually say, and when transferring two can still be reasonable.

Who this article is for

This is for couples in Ahmedabad and Gujarat who are preparing for IVF, or are mid-treatment, and want to understand how the number of embryos transferred is decided — on evidence, not pressure or guesswork. If you have already been told “we will put back two to be safe,” this will help you ask the right questions.

What “embryo transfer” actually means

After eggs are collected and fertilised in the laboratory, one or more embryos are placed into the uterus. The number transferred is a genuine clinical choice, and the language can be confusing:

• Single embryo transfer (SET): one embryo is transferred. When a healthy embryo is deliberately chosen and others are frozen for later, this is called elective single embryo transfer (eSET).
• Double embryo transfer (DET): two embryos are transferred in the same procedure.
• Fresh vs frozen: an embryo can be transferred in the same cycle as egg collection (fresh) or frozen and transferred in a later cycle (frozen embryo transfer). Modern freezing (vitrification) is highly effective, which is what makes a one-at-a-time strategy practical.
• Blastocyst: an embryo grown in the lab to around day 5–6. Culturing to the blastocyst stage helps the team select the embryo most likely to implant, which strengthens the case for transferring just one.

Does transferring two embryos double the chance of a baby?

This is the heart of the matter, and it deserves an honest answer in two parts.

In a single fresh cycle, two embryos do give a somewhat higher chance of a birth than one. Pooled data from randomised trials put the live-birth rate after a single fresh transfer at roughly 27%, compared with around 42% after a double transfer [Source: Cochrane / individual-patient-data meta-analysis, Pandian et al.]. So the “two is better” instinct is not imaginary — in that one cycle, it is real.

But a single cycle is the wrong unit to judge by. What matters is your chance of a baby from one egg collection — including the embryos you freeze. When a fresh single transfer is followed by a frozen single transfer, the cumulative live-birth rate becomes comparable to a double transfer: in the region of 38% versus 42% in earlier data, and roughly 48% versus 49% in more recent analysis [Source: systematic reviews and meta-analyses of SET vs DET]. In other words, transferring your embryos one at a time can give you a similar overall chance of a baby — while avoiding the main risk of putting two back at once.

The real trade-off: twins are the main avoidable risk of IVF

The difference between one embryo and two is not really about whether you have a baby. It is about whether you have twins. And here the numbers are striking. The multiple-birth rate is around 2% after single embryo transfer, compared with about 29% after double transfer [Source: meta-analyses of SET vs DET]. Across two single transfers versus one double transfer, the gap is even wider — on the order of under 1% versus nearly 18%. After single embryo transfer, the chance of twins is close to that of a natural pregnancy.

It is easy to think of twins as a happy shortcut — one pregnancy, two babies, done. As doctors, we have to be honest that a twin pregnancy is not a bonus prize; it is the single most significant avoidable complication of IVF. Compared with a single pregnancy, twins carry a materially higher risk of:

• premature birth, and the long admissions to neonatal intensive care that can follow;
• low birth weight and its consequences for the babies;
• pre-eclampsia, gestational diabetes, and other complications for the mother;
• higher rates of caesarean delivery and postnatal complications.

This is why the framing matters: transferring two embryos raises the chance of twins far more than it raises the chance of a baby. The goal of good fertility care is not simply a positive pregnancy test — it is one healthy baby, and a mother who comes through the pregnancy well.

What ESHRE and ASRM actually recommend

This is not a fringe opinion. It is the settled position of the major international fertility bodies.

The European Society of Human Reproduction and Embryology (ESHRE) published a dedicated guideline in 2024, Number of embryos to transfer during IVF/ICSI. Its central conclusion is unambiguous: “no clinical or embryological factor per se justifies a recommendation of double embryo transfer instead of elective single embryo transfer” — that is, there is no group of patients for whom routinely transferring two is clearly more beneficial than transferring one. ESHRE frames eSET, combined with freezing surplus embryos, as the preferred approach to safe and effective treatment [Source: ESHRE guideline, Human Reproduction, 2024].

The American Society for Reproductive Medicine (ASRM) reaches the same place: a single embryo should be transferred for most patients with a good prognosis — particularly women under 35, and whenever a good-quality blastocyst is available — precisely to limit multiple pregnancy [Source: ASRM committee guidance on limits to the number of embryos to transfer].

Both bodies are describing a default, not a rigid rule. The point is that the burden of proof sits with double transfer, not single — the question is “is there a good reason to transfer two?” rather than “is there a reason not to?”

When is double embryo transfer reasonable?

Medicine is individual, and a thoughtful specialist does not apply a single rule to everyone. There are situations where transferring two embryos is a defensible, shared decision — for example, depending on:

• Age and prognosis. With increasing age, or where embryo quality is limited, the balance can shift — though even here, top-quality embryos are often best transferred one at a time.
• Embryo quality and stage. The selection advantage of a single good blastocyst is different from the situation with earlier-stage or lower-grade embryos.
• Number of embryos available. A one-at-a-time strategy depends on having embryos to freeze; this is part of the conversation.
• Previous cycles. A history of several good-quality single transfers that did not implant changes the discussion.
• Uterine factors and your own priorities. Your medical history, and what matters to you, are legitimate parts of the decision.

The key is that double transfer should follow an honest, individualised conversation about the twin risk — not a blanket habit of “putting two back to be safe.” Crucially, a twin pregnancy is far harder to undo than it is to prevent.

Questions worth asking your fertility specialist

• For my age and embryo quality, is single embryo transfer the recommended option?
• If we transfer one and freeze the rest, what is my cumulative chance of a baby across those embryos?
• What would my specific risk of twins be if we transferred two — and what would that mean for the pregnancy?
• Are we able to grow embryos to the blastocyst stage to help choose the best single one?
• If you are recommending two, what is the specific reason in my case?

Fertility care in Ahmedabad: the same goal, the safer route

Ethical, evidence-based IVF aims for a single healthy baby and a healthy mother — and chooses the strategy most likely to achieve that with the least avoidable risk. At Balaji Horizon Women’s Hospital, on Science City Road in Ahmedabad, fertility planning is individualised: elective single embryo transfer is offered as the sensible default for good-prognosis patients, supported by good laboratory embryo selection and reliable freezing, with the number of embryos always decided through an honest conversation rather than a fixed habit. In India, where practice still varies between clinics, asking why a particular number is being recommended is entirely reasonable — and a sign of an engaged patient, not a difficult one.

When to seek advice

If you are about to start IVF, or are deciding how many embryos to transfer in an upcoming cycle, it is worth having this specific conversation in advance — ideally before egg collection, so the plan is clear. If you have had a previous transfer that did not succeed, a review of embryo quality and strategy can help refine the next step.

A note on next steps

For individualised fertility planning, our team can help. Read more on our IVF page, or our related guide on when to move from IUI to IVF.

Frequently asked questions

How many embryos are transferred in IVF in India?

For most patients with a good prognosis, a single embryo is transferred — this is the approach recommended by international guidelines (ESHRE, ASRM) to give a comparable cumulative chance of a baby while greatly reducing the risk of twins. Some situations make transferring two reasonable, but it should be an individualised decision, not a routine. Indian practice varies between clinics, so it is fair to ask why a particular number is being recommended for you [Source: ESHRE guideline, Human Reproduction, 2024].

Does transferring two embryos double the chance of success?

No. In a single fresh cycle, two embryos give a somewhat higher chance than one (roughly 42% versus 27% live birth in pooled data), but when you transfer your embryos one at a time — a fresh single transfer followed by a frozen one — the cumulative chance of a baby becomes comparable to a double transfer. What two embryos clearly do increase is the chance of twins [Source: meta-analyses of SET vs DET].

Is single embryo transfer less successful?

Per individual transfer, single transfer has a slightly lower birth rate than double. But judged correctly — by your chance of a baby from one egg collection, including frozen embryos — elective single embryo transfer gives a comparable overall result, with far fewer twin pregnancies. That is why it is recommended as the default for good-prognosis patients.

What are the risks of twins from IVF?

Twin pregnancies carry materially higher risks than single pregnancies, including premature birth, low birth weight, neonatal intensive care admission, pre-eclampsia, and gestational diabetes. This is the main reason fertility bodies recommend single embryo transfer: it brings the chance of twins down close to that of a natural pregnancy.

Can I choose to have twins through IVF?

Deliberately aiming for twins is not recommended, because of the significantly higher risks to both mother and babies. Your specialist can explain those risks for your specific situation. The aim of ethical fertility care is one healthy baby at a time, not the most babies in one pregnancy.

Disclaimer: This article is for educational purposes only and does not replace a consultation with a qualified fertility specialist. Decisions about the number of embryos to transfer should be made individually with your treating doctor.

Written by the clinical team at Balaji Horizon Women’s Hospital, Ahmedabad, and medically reviewed by Dr. Priyadatt Patel (MBBS, MS — Obstetrics & Gynaecology), specialist in IVF, reproductive medicine and advanced laparoscopic gynaecology. Aligned with ESHRE (2024) and ASRM guidance. Last reviewed: June 2026.

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