Key takeaways

  • Most IVF twins come from transferring two embryos (double embryo transfer), not from chance, so the number is largely within your control.
  • Twin pregnancies carry 3 to 5 times the preeclampsia risk, over 50 percent preterm birth, and 50 to 60 percent NICU admission compared with singletons.
  • An Indian NICU stay for premature twins can run into many lakhs and is mostly paid out of pocket, costs that often exceed a single-transfer-plus-frozen-cycle strategy.
  • Single embryo transfer (SET) cuts the twin rate from 20 to 35 percent down to 2 to 5 percent without sacrificing your cumulative chance of a baby.
  • ISAR and FOGSI recommend a healthy single baby, not twins, as the goal of IVF, and many leading clinics now offer SET as first-line for good-prognosis patients.

How IVF Twins Happen: Fraternal vs Identical

IVF twins arise in two distinct ways, and the difference matters for risk.

Fraternal (dizygotic) twins are the more common IVF type. They occur when two embryos are transferred and both implant. Each twin develops from its own embryo, with its own placenta and amniotic sac (dichorionic, diamniotic, or DCDA). They are no more alike than ordinary siblings, can be different sexes, and carry the lowest twin risk profile. Fraternal twin rates track directly with how many embryos go in: one embryo gives a near-zero fraternal twin rate, two embryos give roughly 20 to 35 percent, and three embryos push it to 30 to 45 percent plus a 5 to 15 percent triplet risk.

Identical (monozygotic) twins are less common but striking, because IVF raises the natural rate. In the general population, identical twins occur in about 0.3 to 0.4 percent of pregnancies, when a single fertilised embryo splits into two genetically identical embryos within 14 days of fertilisation. In IVF, the identical twin rate climbs to 1 to 5 percent, several times higher. The reasons are debated but include blastocyst culture (where most IVF splitting occurs), ICSI, assisted hatching (opening the zona pellucida), culture media effects, and possibly maternal age. To understand the underlying biology, our explainer on identical versus fraternal twins breaks down how each type forms.

Identical twins can be monochorionic monoamniotic (MCMA, one shared placenta and sac, highest risk), monochorionic diamniotic (MCDA, shared placenta, separate sacs, moderate risk), or dichorionic diamniotic (DCDA, separate placentas and sacs, lowest risk). Because splitting can happen even after single embryo transfer, SET reduces but does not entirely eliminate twin risk. Higher-order multiples (triplets, quadruplets) are almost always an unintended consequence of IVF or ovulation induction, and rates have dropped sharply as single transfer has become standard.

Maternal Risks: Preeclampsia, Diabetes, Hyperemesis, Bleeding

A twin pregnancy places far greater strain on the body at every stage.

Preeclampsia, the combination of high blood pressure, protein in the urine, and organ stress, is 3 to 5 times more common in twins, affecting 15 to 25 percent of twin pregnancies. It can escalate to eclampsia (seizures), HELLP syndrome, placental abruption, and stroke, and severe cases often force an early delivery. FOGSI and Indian preeclampsia guidance recommend low-dose aspirin (75 to 150 mg) from 12 weeks for high-risk women, which includes anyone carrying twins.

Other maternal risks rise too:

  • Gestational diabetes is about twice as common.
  • Severe nausea and vomiting (hyperemesis gravidarum) is more frequent and more intense.
  • Anaemia is common because two babies demand more iron and folate.
  • Polyhydramnios and oligohydramnios (too much or too little fluid) both occur more often.
  • Pregnancy-induced hypertension and cholestasis of pregnancy are more frequent.

Delivery carries its own load. Over 70 percent of Indian twin pregnancies end in caesarean section, often emergency rather than planned. Postpartum haemorrhage is roughly twice as likely, with higher rates of retained placenta and uterine atony. Recovery is slower too, with more pelvic floor strain, urinary incontinence, a longer breastfeeding ramp-up, and higher rates of postpartum depression. Globally, including in India, maternal mortality is higher in twin pregnancies than in singleton ones.

Newborn Risks: Preterm Birth, Low Weight, NICU, Long-Term Outcomes

For the babies, prematurity is the central problem. Over half of twin pregnancies deliver before 37 weeks, compared with about 10 percent of singletons. Most twin preterm births are late preterm (32 to 36 weeks), but a meaningful share arrive very preterm (28 to 31 weeks) or extremely preterm (under 28 weeks), and the earlier the birth, the higher the risk. Our guide to preterm labour and premature birth covers the warning signs to watch for.

Twins also tend to be smaller. Average twin birth weight is around 2.3 to 2.5 kg versus 3.0 to 3.3 kg for singletons, with very low (under 1.5 kg) and extremely low (under 1 kg) birth weights more common.

NICU admission is the norm rather than the exception: 50 to 60 percent of twins are admitted, against 10 to 15 percent of singletons. Common NICU issues include:


Longer term, cerebral palsy is 4 to 6 times more common in twins (roughly 1 to 2 percent of twin births), developmental delay is 2 to 5 times more common, and vision, hearing, and learning difficulties all occur more often. Perinatal mortality is about 4 times that of singletons. These are not abstract statistics; they are everyday realities in Indian NICUs. Speaking with a paediatrician or neonatologist before deciding on embryo number can add a perspective that fertility-clinic counselling sometimes leaves out.

The Indian NICU Reality: Capacity, Cost, and Access

The NICU side of IVF twins is the part fertility conversations most often skip, and in India it deserves close attention.

Capacity is uneven. Level-3 NICUs, the ones equipped for very preterm or critically ill newborns, are concentrated in major metros (Delhi NCR, Mumbai, Bengaluru, Chennai, Hyderabad, Pune, Kolkata, Ahmedabad) and a few tier-2 cities. Many tier-3 and tier-4 towns have limited or no level-3 capacity, so a family delivering away from a major centre may face an urgent transfer of fragile newborns, with all the disruption that brings. The continuity of kangaroo mother care and skin-to-skin contact becomes harder to maintain when babies are moved.

Cost is the harder reality. Government and trust hospitals (AIIMS, KEM Mumbai, government medical colleges, ESI hospitals) offer subsidised or free care for eligible families but are capacity-constrained. Private and corporate NICUs typically charge ₹50,000 to ₹2 lakh per week, depending on the level of care and ventilation needs. Premature twins needing 4 to 12 weeks of care can each accumulate ₹5 lakh to ₹25 lakh, so a twin NICU bill can reach ₹10 lakh to ₹50 lakh for the pair.

Most of this is paid out of pocket. Many Indian health policies cap NICU coverage with sub-limits (often ₹1 to 5 lakh per claim), and IVF-related complications may be excluded altogether. Long-term costs of prematurity, such as physiotherapy, occupational and speech therapy, vision and hearing follow-up, and cerebral palsy management, can continue for years. Families facing extreme prematurity sometimes deplete savings, take loans, or turn to crowdfunding. These numbers belong squarely in any single-versus-double transfer decision.

Why Double Embryo Transfer Persists in India

Despite strong evidence for single transfer, double embryo transfer (DET) is still common in India for understandable reasons.

Cost pressure is the most cited driver. A fresh IVF cycle runs ₹1.2 lakh to ₹2.5 lakh, with ICSI, frozen embryo transfer, and PGT-A adding more, and almost all of it is self-funded because Indian insurance rarely covers infertility. Couples naturally want to maximise the chance per cycle, and transferring two embryos feels like better value. A clear look at IVF cost and success rates in India helps separate that instinct from the actual numbers.

Cultural twin preference is real and openly voiced. Twins are often seen as a blessing and an efficient way to complete a family, and elders, in-laws, and friends may actively encourage transferring two embryos in the hope of twins.

Misconceptions add fuel: that DET reliably doubles success, that a twin pregnancy is simply a singleton with a bonus baby, that modern NICUs make prematurity a non-issue, and that SET is needlessly cautious.

Clinic and system factors matter too. Some clinics still default to DET out of habit or patient demand, and a few smaller units lack the embryology capability for reliable blastocyst culture that makes SET most effective. With no insurer rewarding SET (as happens in some Western systems), there is little financial nudge toward it. And many patients first hear about SET only at the consultation, with little time to research. ISAR position papers from 2018 onward have pushed for SET, and major networks now offer it as first-line for younger patients with good blastocysts. The shift is underway, but it depends on patient education and changing clinic habits.

What ISAR and FOGSI Recommend on Embryo Transfer Numbers

When selective double transfer may be reasonable

SET is the default, not an absolute rule. A clinician may discuss DET for older patients, those with poorer-quality embryos, or after repeated implantation failure, where the realistic per-transfer odds with one embryo are low. The point is a deliberate, individualised decision, not a routine default to two embryos. If you fall into one of these categories, ask your specialist to walk you through your specific age-stratified success rates for SET versus DET.

Identical Twins Can Still Happen After Single Transfer

An important nuance: identical (monozygotic) twinning can occur even with a single embryo transfer, though the chance is small. The natural identical-twin rate is about 0.3 to 0.4 percent, while IVF with single transfer runs at 1 to 5 percent. The exact reasons are unclear but likely involve blastocyst culture (where most splitting occurs), ICSI, assisted hatching, culture media, and possibly maternal age.

Identical twins share genetic material because a single embryo splits within 14 days of fertilisation. They can be:

  • MCMA (one placenta, one sac): highest risk, including cord entanglement and very high rates of twin-to-twin transfusion syndrome.
  • MCDA (shared placenta, separate sacs): twin-to-twin transfusion syndrome (TTTS) occurs in roughly 10 to 15 percent.
  • DCDA (separate placentas and sacs): risks similar to fraternal twins.

Twin-to-twin transfusion syndrome, where blood flow is shared unequally between twins, is a serious complication of a shared placenta and may need specialist fetal-medicine care, sometimes fetoscopic laser surgery, available at centres such as AIIMS Delhi, KEM Mumbai, and PGI Chandigarh among others. The detailed mechanics of chorionicity and TTTS are covered in our twin and multiple pregnancy guide.

Even with this small residual risk, SET dramatically lowers the overall twin rate, typically to 2 to 5 percent combined, against 20 to 35 percent with DET. ISAR recommends counselling patients about this so expectations stay accurate.

If You Are Already Carrying IVF Twins: Antenatal Care

If you are pregnant with twins, focused antenatal care genuinely improves outcomes. ACOG, FIGO, FOGSI, and POGS twin-pregnancy guidelines converge on a few essentials.

Confirm chorionicity early. A first-trimester scan at 11 to 13 weeks should establish whether the twins share a placenta (monochorionic, higher risk) or have separate ones (dichorionic). This shapes the entire monitoring plan, so it sits at the heart of twin pregnancy management.

Choose the right hospital. Aim for a centre experienced in twin deliveries with a level-3 NICU on site, ideally a tertiary or major maternity unit.

Supplement and screen. Low-dose aspirin (75 to 150 mg from 12 weeks) is recommended for preeclampsia prevention. Iron and folate are given at higher doses than in singleton pregnancy to prevent anaemia, alongside calcium and vitamin D, all of which feature in standard pregnancy supplement guidance. A glucose tolerance test is done at 24 to 28 weeks (and repeated later) because gestational diabetes is more common.

Monitor closely. Scans every 4 weeks for dichorionic twins and every 2 weeks for monochorionic twins from 16 weeks, checking growth, fluid, Dopplers, and TTTS. Antenatal visits intensify toward term, with blood pressure checked every visit.

Prepare for early delivery. A steroid course (betamethasone) supports fetal lung maturity if preterm birth threatens, and magnesium sulphate offers neuroprotection if birth is likely before 32 weeks. Dichorionic twins typically deliver by 37 to 38 weeks, MCDA by 36 to 37 weeks, and MCMA by 32 to 34 weeks via planned caesarean. Vaginal birth is possible for some twins when the first twin is head-down and the team is experienced, but caesarean is common. Packing your hospital bag earlier than a singleton pregnancy is wise.

Deciding Between One Embryo and Two: A Counselling Framework

If you are choosing between single and double transfer, a structured conversation helps clarify what matters most.

Ask your fertility specialist:

  • What is my prognosis category (age, AMH, embryo quality, prior cycles), and does it make me a SET candidate?
  • What is the per-transfer difference between SET and DET for my situation?
  • What is my cumulative success over SET plus frozen transfers versus a single DET cycle?
  • What is my personal twin risk with DET?
  • What are the NICU realities and cost projections at my planned delivery hospital?
  • What is the total cost of a SET strategy (with frozen cycles) versus DET?

Ask yourself and your partner, privately:
  • Is our priority a healthy single baby, or a chance at twins?
  • Are we prepared for twin-pregnancy complications, a possible NICU stay, and long-term challenges?
  • Are we ready for the practical and financial load of two infants at once?
  • Are we deciding freely, or under family pressure?

If family expectations are shaping the decision, consider including relatives in a counselling session so they understand the medical risks; most ISAR- and FOGSI-affiliated clinics support this when patients ask. Whatever you choose, document the embryo-transfer decision in writing in your treatment plan so there is no confusion on transfer day. The decision is yours, but it should rest on complete information about risks, costs, and alternatives. If you are still early in your journey, comparing IUI versus IVF and reviewing common fertility abbreviations can make these conversations far easier.

When to See a Doctor

Twin pregnancies need closer watching than singletons. If you are carrying twins, seek prompt medical care for any of the following:

  • A severe or persistent headache, vision changes (flashing lights, blurring), or sudden swelling of the face and hands, which can signal preeclampsia.
  • Upper-abdominal or right-sided rib pain, which may point to HELLP syndrome.
  • Any vaginal bleeding, or a sudden gush or trickle of fluid.
  • Regular tightening or cramping before 37 weeks, which may be preterm labour.
  • Reduced or absent movements from either baby.
  • Severe, unrelenting vomiting that prevents you from keeping fluids down.

If you are still in the planning stage, the right time to discuss single versus double transfer is before the cycle, not on transfer day. A calm, informed conversation with your reproductive specialist, ideally with a paediatrician's perspective on NICU outcomes, is the single most useful step you can take.

Myths vs Facts

Frequently asked questions

Does transferring two embryos double my chance of a baby?

No. In good-prognosis patients, transferring two embryos mainly raises the chance of twins, not the chance of taking home a baby. Over a single transfer plus a frozen transfer, the cumulative odds of a baby are similar to one double transfer, but with far lower twin risk. Your specialist can give you the per-transfer and cumulative numbers for your specific situation.

Are IVF twins more dangerous than naturally conceived twins?

The core risks are similar, because they stem from carrying two babies, not from IVF itself. The main difference is that IVF twins are usually preventable through single embryo transfer, whereas naturally conceived twins are not. IVF also slightly raises the chance of identical twinning, which carries its own placenta-sharing risks.

Can I still have twins if I choose single embryo transfer?

Yes, but the chance is small. A single embryo can split into identical twins in 1 to 5 percent of cases, so the combined twin rate with single transfer is about 2 to 5 percent, compared with 20 to 35 percent with double transfer.

Why do so many Indian clinics still offer double embryo transfer?

Cost pressure (IVF is largely self-funded in India), cultural preference for twins, misconceptions about success rates, and historical clinic habits all play a part. ISAR and FOGSI now recommend single transfer as first-line, and major networks are increasingly adopting it for good-prognosis patients.

How much does a NICU stay for premature twins cost in India?

Private NICUs typically charge ₹50,000 to ₹2 lakh per week. Premature twins needing several weeks of care can each accumulate ₹5 lakh to ₹25 lakh, so a combined bill can reach ₹10 lakh to ₹50 lakh, most of it paid out of pocket because insurance NICU coverage is usually limited.

Is it safe to ask my doctor for twins?

Requesting twins is understandable, but transferring extra embryos specifically to try for twins is considered medically inappropriate by ASRM, ESHRE, ISAR, and FOGSI because of the higher risks to mother and babies. A good clinic will counsel you toward a healthy single baby as the goal.

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