Carrying twins means two babies to watch, and the single most important question is answered at the first-trimester scan: do they share a placenta? Twins who share one (monochorionic twins) have connected blood vessels on its surface, and that shared circulation can become unbalanced. They need scans every two weeks from 16 weeks; twins with separate placentas are scanned about every four weeks.
Twin pregnancies are more common than they used to be, largely because of IVF and pregnancies at older ages. Compared with a single pregnancy, a twin pregnancy carries a higher chance of preterm birth, anaemia, gestational diabetes, pre-eclampsia and growth problems. Most of these can be anticipated, screened for and managed when the schedule is right from the start.
Dr. Devang Patel manages twin and triplet pregnancies from the first scan through delivery, including surveillance for twin-to-twin transfusion syndrome (TTTS) and selective growth restriction. His maternal-fetal medicine training at Fernandez Hospital and FMF (UK) accreditation underpin the scanning, and deliveries take place at Divine Women’s Hospital, Gota, with 24×7 neonatal support.
Types of twin pregnancy
Twins are described by how many placentas (chorion) and sacs (amnion) they have. This, rather than whether they are identical, decides how closely they need watching. All non-identical twins have separate placentas; about two-thirds of identical twins share one.
Chorionicity is most reliable when seen between 11 and 14 weeks, using the shape of the membrane where it meets the placenta (the lambda or T sign). If it cannot be determined, the pregnancy is managed as monochorionic until proven otherwise.
| Type | What it means | Scan frequency and main concerns |
|---|---|---|
| Dichorionic diamniotic (DCDA) | Two placentas, two sacs. About 70–80% of twins | Every 4 weeks from 20 weeks; growth difference, preterm birth |
| Monochorionic diamniotic (MCDA) | One shared placenta, two sacs | Every 2 weeks from 16 weeks; TTTS, selective growth restriction, TAPS |
| Monochorionic monoamniotic (MCMA) | One placenta, one sac. About 1% of twins | Close specialist surveillance; cord entanglement, usually delivered by caesarean at 32–34 weeks |
| Triplets and higher | Any combination of the above | Individualised; very high preterm risk, counselling on options early |
Who is more likely to have twins
Non-identical twins come from two eggs released in the same cycle, so anything that raises the chance of double ovulation increases them. Identical twins come from one embryo splitting, which happens largely by chance, though it is somewhat more frequent after IVF.
- Pregnancy after IVF, especially when more than one embryo is transferred
- Ovulation induction with tablets or injections
- Mother aged 35 or above
- Family history of non-identical twins on the mother’s side
- Previous twin pregnancy and higher number of previous births
How a twin pregnancy feels different
Morning sickness is often stronger and lasts longer, because pregnancy hormone levels are higher. The bump grows faster, so backache, breathlessness, heartburn and swollen feet tend to come earlier.
Tiredness is common, partly from the extra demand and partly from anaemia, which is frequent in twin pregnancies in India. Iron and folic acid are usually started early and haemoglobin is checked more often.
Many women with twins find it helpful to plan for reduced work earlier than they would with one baby, often from around 28–32 weeks, and to arrange help at home for the first months after birth. This is not because rest prevents complications, but because the physical load is genuinely greater.
Complications specific to twins sharing a placenta
Twin-to-twin transfusion syndrome affects about 10–15% of monochorionic twins. One baby (the donor) passes blood to the other (the recipient) through placental connections. The donor makes little urine and its sac runs low on fluid; the recipient makes too much. It usually appears between 16 and 26 weeks and can progress quickly, which is why two-weekly scans matter.
Selective fetal growth restriction, where one twin is much smaller because of an unequal share of placenta, affects a similar proportion. Twin anaemia-polycythaemia sequence (TAPS) is a rarer, slower imbalance detected by measuring blood flow in the brain artery (MCA Doppler) of each baby.
When TTTS is diagnosed at a stage that needs treatment, the established option is laser coagulation of the connecting vessels, performed at a specialised fetal therapy centre. Referral is arranged promptly, and care continues here afterwards. Milder stages are often watched with more frequent scans, because a proportion stay stable.
If one twin sadly dies in a monochorionic pregnancy, the surviving twin can be affected by a sudden drop in blood pressure through the shared circulation. Careful counselling, a brain scan of the surviving baby a few weeks later and a delivery plan are part of care in that situation.
Sudden tightness or rapid growth of the abdomen between 16 and 26 weeks in a monochorionic pregnancy needs a scan within 24 hours.
What each scan checks
- Deepest pool of fluid around each baby and whether each bladder is visible
- Estimated weight of each baby and the percentage difference between them (more than 20–25% is significant)
- Umbilical artery Doppler and, in monochorionic twins, MCA Doppler for TAPS
- Cervical length at the anomaly scan, because a short cervix predicts early birth
- Detailed anomaly scan at 18–22 weeks, which takes longer than for a single baby
- Placental position and cord insertions
Mother’s health in a twin pregnancy
The chance of pre-eclampsia is two to three times that of a single pregnancy, so women with twins are often advised low-dose aspirin from 12 weeks if they have one more risk factor. BP and urine are checked at every visit.
Gestational diabetes testing follows the usual 24–28 week window. Calcium, iron, folic acid and protein needs are higher; calorie needs rise moderately, by roughly 300 kcal a day more than for a single pregnancy in the second half.
Preterm birth and how it is managed
About half of twins are born before 37 weeks, and around one in ten before 32 weeks. Routine bed rest, routine progesterone and routine cervical stitch have not been shown to help in all twin pregnancies, so they are used selectively - for example, progesterone or a stitch may be considered when the cervix is found to be short.
If early labour starts or looks likely, steroid injections are given to mature the babies’ lungs, and magnesium sulphate before 32 weeks for brain protection. The neonatal team is involved early.
Timing and mode of delivery
Planned birth reduces the risk of late stillbirth, which rises in twin pregnancies after a certain point. Common guidance is delivery at 37 weeks for uncomplicated DCDA twins and 36 weeks for uncomplicated MCDA twins, with earlier birth if complications arise.
Vaginal birth is a reasonable option when the first twin is head-down and there are no other reasons for caesarean, with the team ready to assist the second baby. Caesarean is usually advised when the first twin is not head-down, for monoamniotic twins, and for most triplets.
Twin labour is monitored continuously, with a separate heart trace for each baby. An epidural is often recommended because it allows the team to help the second baby quickly, by turning or assisted delivery, if needed. The interval between the two births is usually under 30 minutes.
| Situation | Usual timing | Usual mode |
|---|---|---|
| Uncomplicated DCDA | 37+0 weeks | Vaginal if first twin head-down |
| Uncomplicated MCDA | 36+0 weeks | Vaginal if first twin head-down |
| MCMA | 32–34 weeks | Caesarean |
| First twin breech or transverse | As per type | Caesarean |
| Triplets | Around 35 weeks or earlier | Usually caesarean |
After the birth
The risk of heavy bleeding after delivery is higher with twins because the uterus has been stretched more. Medicines to help it contract are given routinely, and blood is kept available. Breastfeeding twins is possible, and support is offered from the first feed, including tandem feeding positions.
At the six-week review, haemoglobin, BP, contraception and mood are checked. A twin pregnancy does not by itself make a future pregnancy high-risk, though if it followed IVF, plans for single embryo transfer are worth discussing.
Your care, step by step
- Chorionicity scanThe first-trimester scan establishes how many placentas and sacs there are, which sets the whole schedule.
- Personalised scan calendarTwo-weekly or four-weekly scans are booked in advance so no window is missed.
- Mother’s screeningBP, haemoglobin, sugar and cervical length are checked at the right weeks, with aspirin and iron started where indicated.
- Delivery planTiming, mode of birth and neonatal support are agreed from around 32 weeks.
- Postnatal and feeding supportBleeding risk is managed actively and help with feeding two babies starts from the first day.
When to book a visit
- An early scan shows two or more babies
- You are expecting twins after IVF or ovulation induction
- You have been told the twins share a placenta
- Your scan shows a weight difference or unequal fluid between the twins
- You have a twin pregnancy and a short cervix, high BP or diabetes
Warning signs - get same-day care
- Sudden rapid enlargement or tightness of the abdomen, especially between 16 and 26 weeks
- Regular tightenings or period-like pains before 37 weeks
- Leaking fluid or bleeding from the vagina
- Reduced movements from either baby
- Severe headache, visual disturbance or upper abdominal pain
Labour and emergency care are available 24 × 7. Call the hospital and come in directly.
Myths and facts
Myth: Twins always need a caesarean.
When the first twin is head-down and there are no other complications, vaginal birth is a reasonable option.
Myth: Identical twins and twins sharing a placenta are the same thing.
About a third of identical twins have separate placentas. Monitoring depends on placentas, not on whether the twins are identical.
Myth: You have to eat for three.
You need more iron, calcium, folic acid and protein, but only about 300 extra calories a day in the second half of pregnancy.
Myth: Bed rest prevents twins from coming early.
Routine bed rest has not been shown to prevent preterm birth in twins and carries its own risks.
Frequently asked questions
Can twins be born normally?
Yes, in many cases. When the first twin is head-down and there are no other complications, vaginal birth is a reasonable option, with the team prepared to assist the second baby.
How do I know if my twins share a placenta?
It is seen on the first-trimester scan, ideally between 11 and 14 weeks, from the shape of the membrane where it joins the placenta. This is why an early scan matters so much in twin pregnancy.
What is TTTS and how is it detected?
Twin-to-twin transfusion syndrome is an imbalance of blood flow between twins who share a placenta. It is detected on scan by unequal fluid around the babies and a missing bladder in the smaller twin, which is why two-weekly scans are done from 16 weeks.
How many weeks are twins usually born?
Around half of twins arrive before 37 weeks. When the pregnancy is uncomplicated, delivery is usually planned at 37 weeks for twins with separate placentas and 36 weeks for twins sharing one.
Do I need to eat for three?
You need more iron, folic acid, calcium and protein, but not double the calories. You will get a diet plan suited to a twin pregnancy, using familiar foods such as dal, paneer, curd, sprouts and green vegetables.
Is NT screening reliable in twins?
The NT scan can be done in twins and gives a chance figure for each baby. Blood-based screening is less precise in twins, so results are interpreted with that in mind.
Will I need a cervical stitch?
Not routinely. A stitch or progesterone may be considered if the cervix is found to be short on scan, after a discussion of the benefits and risks in your situation.
Can I breastfeed twins?
Yes. Many mothers breastfeed twins fully or partly. Feeding support, including tandem positions, starts from the first day after birth.
What is the chance of twins again?
It is slightly higher after non-identical twins, especially with a family history. After IVF it depends mainly on how many embryos are transferred.
How much weight should I gain with twins?
For a woman starting at a healthy weight, a gain of roughly 17–25 kg over the whole pregnancy is commonly quoted. Women who start heavier are advised to gain less. Steady gain matters more than the exact number, and it is reviewed at each visit.