£340Twin scan, each baby examined individually
Twin Pregnancy Scans in London
Finding out you are expecting twins brings more scans, more questions and a lot to take in. Our twin pregnancy scan examines, measures and reports on each baby individually, at any stage from 10 to 40 weeks, at LPC City in Spitalfields and LPC West in Chelsea.
This page explains how twins are seen on a scan, why the type of twin pregnancy matters more than whether your babies are identical, and how the free NHS twin care pathway works, so that any private scan adds to your NHS care rather than replacing it.
10–40 weeksAt LPC City (E1) and LPC West (SW10)
Available atLPC City (E1)LPC West (SW10)
Your NHS twin care comes first
If you are expecting twins in the UK, the NHS provides specialist antenatal care free of charge: a named team experienced in twin pregnancy, a first-trimester scan at around 11 to 14 weeks to date the pregnancy and identify the type of twins, and regular scans after that. Twins sharing a placenta are scanned every two weeks from 16 weeks. Please go to every appointment you are offered. Our scans are an addition to that care, never a substitute: for example an earlier look, a detailed early fetal scan, NIPT with a scan, or a second opinion between NHS visits. Our prices are all on the fees page.
When can twins be seen on a scan?
In some pregnancies, twins can be seen on an ultrasound scan from about 6 weeks, when two pregnancy sacs may be visible. Heartbeats become easier to confirm over the following weeks. Our viability scan, available from 6 to 9 weeks and best from 7 weeks, dates the pregnancy, checks each heartbeat and counts how many babies there are. For many parents, this is where they first find out.
On the NHS, twins are usually found at the 12-week dating scan. You might already suspect twins if you seem bigger than expected for your dates, twins run in your family, or you have had fertility treatment such as IVF.
A very early count is not always final. Sometimes a second sac seen at 6 or 7 weeks stops developing and is gradually reabsorbed, known as vanishing twin syndrome. This is one reason the first-trimester scan at 11 to 14 weeks matters so much in a twin pregnancy: it confirms how many babies are developing and what type of twins they are.
Twin pregnancy in numbers
1 in 3 Twins who are identical; the other two-thirds are non-identical (NHS)
14 weeks A scan before 14 weeks should be able to show accurately what kind of placenta your twins have (NHS)
10–15% Twin pregnancies sharing a placenta (monochorionic) that develop twin-to-twin transfusion syndrome (NHS, Twins Trust)
6 in 10 Twins born before 37 weeks, which is why planned birth and preterm-birth planning are part of twin care (NHS, NICE NG137)
DCDA, MCDA and MCMA: the three types of twin pregnancy
For medical purposes, twin pregnancies are described by how many placentas (the chorion) and how many amniotic sacs (the amnion) the babies have. This is called chorionicity and amnionicity. It shapes your care far more than whether the twins are identical: NICE guidance is explicit that the risks in a twin pregnancy are determined by chorionicity, not zygosity.
Separate placentas, separate sacs
DCDA: dichorionic diamniotic
Each baby has its own placenta and its own sac. All non-identical twins are DCDA, and so are some identical twins. The risks to the babies in the womb are much lower than with a shared placenta. The NHS usually scans DCDA twins every 4 weeks from 20 weeks.
Shared placenta, separate sacs
MCDA: monochorionic diamniotic
The babies share one placenta but each has its own sac. Most identical twins are MCDA. Blood vessels joining the babies' circulations across the shared placenta create a risk of twin-to-twin transfusion syndrome, so the NHS scans MCDA twins every 2 weeks from 16 weeks.
Shared placenta, shared sac
MCMA: monochorionic monoamniotic
The babies share both the placenta and the sac. This is much rarer. Their umbilical cords can become entangled, so NICE recommends individualised care from a consultant at a tertiary (specialist) fetal medicine centre, and the NHS notes you will have frequent scans.
Why the type of twins is best confirmed before 14 weeks
NICE recommends confirming chorionicity and amnionicity as soon as a twin pregnancy is detected, ideally at the same first-trimester scan that dates the pregnancy (at about 11+2 to 14+1 weeks). The sonographer looks at three things: how many placental masses there are, the membrane dividing the sacs and how thick it is, and where that membrane meets the placenta.
That meeting point gives two classic ultrasound signs:
- The lambda sign: placental tissue extends into the base of a thick dividing membrane, forming a triangular peak shaped like the Greek letter λ. This indicates two placentas (dichorionic twins).
- The T-sign: a thin membrane meets a single placenta at a right angle, like the letter T. This indicates a shared placenta (monochorionic twins).
As pregnancy goes on, two placentas lying side by side can grow together and the dividing membrane thins, so these signs become harder to read. The NHS notes that a scan done before 14 weeks should be able to show accurately what kind of placenta your twins have. After 14 weeks, NICE advises using every available sign, including whether the babies are of different sexes. If the type still cannot be determined, the pregnancy should be managed as monochorionic until proven otherwise, because that is the safer assumption.
Your NHS twin scan schedule
NICE guideline NG137 sets out the minimum scans and appointments the NHS should offer in an uncomplicated twin pregnancy. Your own schedule may include more visits if anything needs a closer look.
| Type of twins | Scans offered (weeks of pregnancy) | Minimum antenatal appointments | Planned birth offered |
|---|---|---|---|
| DCDA (separate placentas) | 11–14, then 20, 24, 28, 32 and 36 (roughly every 4 weeks from 20) | At least 8, including 2 without a scan at 16 and 34 weeks | At 37 weeks |
| MCDA (shared placenta, separate sacs) | 11–14, then every 2 weeks: 16, 18, 20, 22, 24, 26, 28, 30, 32 and 34 | At least 11 | At 36 weeks |
| MCMA (shared placenta and sac) | Individualised, with frequent scans at a tertiary fetal medicine centre | Individualised | Between 32+0 and 33+6 weeks |
Source: NICE NG137, Twin and triplet pregnancy (2019); planned-birth timings also given by the NHS. The 20-week scan in each schedule is the anomaly scan.
Each NHS scan also compares the babies' estimated weights: from 16 weeks in twins sharing a placenta, and from 24 weeks in twins with separate placentas. NICE advises closer monitoring if the difference reaches 20% or more, or if either baby measures below the 10th centile.
Why twin pregnancies are monitored more closely
Most twin pregnancies are healthy and end with healthy babies. The extra scans exist because some complications are more common when you are carrying two:
- Iron-deficiency anaemia: NICE recommends an extra full blood count at 20 to 24 weeks as well as the usual checks
- Pre-eclampsia, which is more likely in a multiple pregnancy
- Premature birth: around 6 in 10 twins are born before 37 weeks, and the NHS says women with twins should be offered a cervical length scan between 16 and 20 weeks
- Differences in growth between the babies, which is why the babies' estimated weights are compared at every scan (from 16 weeks if they share a placenta, from 24 weeks if not)
- In twins sharing a placenta, twin-to-twin transfusion syndrome (TTTS) and twin anaemia polycythaemia sequence (TAPS)
Twin-to-twin transfusion syndrome (TTTS)
TTTS can only happen when twins share a placenta. Blood vessels on the shared placenta connect the two babies' circulations. Usually blood flows evenly between them. In TTTS the flow becomes unbalanced: one baby (the donor) gives away blood and produces less amniotic fluid, while the other (the recipient) receives too much, and the fluid around it builds up. TTTS affects around 10 to 15 per cent of monochorionic twin pregnancies. It can happen at any stage, but Twins Trust notes it is most often diagnosed before 24 weeks.
Because TTTS is usually picked up on scans rather than through symptoms, NICE recommends ultrasound every 2 weeks from 16 weeks until birth for all monochorionic twin pregnancies. Each scan measures the deepest pocket of fluid on either side of the dividing membrane. It also checks for growth problems and TAPS, a rarer and more gradual imbalance in blood counts. If TTTS is diagnosed, you should be referred to a tertiary fetal medicine centre, where treatments such as fetoscopic laser surgery on the placenta are available.
We do not treat TTTS at London Pregnancy Clinic. If a scan with us raises any concern, we will explain what we have seen, give you a written report and advise you to contact your NHS twin team or maternity unit straight away.
What our twin pregnancy scan includes
A twin pregnancy scan is the scan that suits your stage of pregnancy, with each baby examined, measured and reported on individually. That takes around twice as long as scanning one baby, which is why the price is our standard £260 scan plus an £80 twin supplement: £340 in total, from 10 to 40 weeks.
10–16 weeks
Early anomaly check for each baby
Each baby's anatomy is checked as in our 10-week scan or early fetal scan, and we look at the placentas and membranes to assess the type of twins. It can be combined with NIPT at the same visit (see below).
20–29 weeks
Detailed anomaly scans
A structural survey of each baby, as in our anomaly scan at 20–25 weeks or our third-trimester anomaly scan at 26–29 weeks.
30–40 weeks
Growth, fluid and wellbeing
Each baby's growth, amniotic fluid and Doppler blood flow, as in our wellbeing scan, with the babies' estimated weights compared, and each baby's position in our presentation scan.
Specialist opinion
Scans with our senior specialists
Twin scans with Dr Fred Ushakov or Ms Diane Nzelu cost their specialist rate of £360 plus the £80 twin supplement, with the difference paid at the clinic. Early heart scans for twins are available through our early fetal echocardiography.
After your scan
Report and images
You receive a written report covering each baby, which you can share with your NHS team, and ultrasound images once we are satisfied the pregnancy is developing as expected.
Two London clinics
City and West London
LPC City, 1st Floor, 36 Spital Square, E1 6DY, and LPC West, 10 Redcliffe Street, SW10 9DT. A £30 supplement applies to evening, weekend and bank holiday appointments.
NIPT in a twin pregnancy
Non-invasive prenatal testing (NIPT) analyses DNA from the placenta that circulates in your blood, to screen for conditions such as Down's syndrome. It works in twin pregnancies too. In a 2021 meta-analysis covering 137 twin pregnancies affected by Down's syndrome, NIPT detected 99.0 per cent (95% CI 92.0–99.9%) with a false-positive rate of 0.02 per cent. That is high, but lower than in singleton pregnancies, and there were too few cases of Edwards' and Patau's syndromes to measure performance for those precisely (Judah et al., 2021).
On the NHS, the combined test at the 11 to 14-week scan is the screening test of choice for twins, with NIPT offered free if that result shows a higher chance (between 1 in 2 and 1 in 150).
Not every NIPT is validated for twins. Among the tests we offer, PrenatalSafe and PrenatalSafe Complete Plus are suitable for twin pregnancies (in twins, Complete Plus screens a narrower range of conditions and does not include microdeletions or sex chromosome conditions), and Panorama can be used for twins without its microdeletion screens, including 22q11.2 (DiGeorge).
The SMART Test (KNOVA) has only been validated in singleton pregnancies, so we cannot offer it for twins. NIPT is always booked together with a scan, never on its own, and our genetic counselling team can help you choose.
What NIPT can and cannot tell you with twins
- Which baby? With non-identical twins, a higher-chance result cannot say which baby is affected. NHS screening standards require twin reports to state that one or both babies may have the condition.
- Confirming a result: a higher-chance result needs a diagnostic test (CVS or amniocentesis) to confirm it. In twins this is done at a specialist fetal medicine unit, and the NHS notes the miscarriage risk is about twice that in a singleton pregnancy.
- Sex of each baby: a Y-chromosome signal shows that at least one baby is likely to be a boy, but the accuracy of standard NIPT for telling the sex of each twin is not well established. Your later scans can show each baby's sex.
- Identical or not: Panorama's SNP-based method is designed to report whether twins are identical (zygosity) and the sex of each baby. In its validation study, zygosity was correctly identified in 93 of 93 twin pregnancies. Ask at your pre-NIPT consultation what your chosen test will report for twins.
Twin pregnancy scans: your questions answered
How early can a scan show twins?
In some pregnancies, two pregnancy sacs can be seen from about 6 weeks, with heartbeats easier to confirm over the following weeks. Our viability scan (6–9 weeks, best from 7) counts how many babies there are. Very early findings can change, so the type of twins is confirmed at the 11 to 14-week scan.
Can a scan tell whether my twins are identical?
Not directly. A scan shows whether the babies share a placenta, which is what matters most for your care. Twins sharing a placenta are identical. Twins with separate placentas may be identical or non-identical, unless they are different sexes, in which case they are non-identical. The NHS notes that the most accurate confirmation is a DNA test after birth, although some NIPT tests can estimate zygosity during pregnancy.
How much does a twin pregnancy scan cost?
£340 at LPC City or LPC West, at any stage from 10 to 40 weeks: our standard £260 scan plus an £80 twin supplement. A £30 supplement applies to evenings, weekends and bank holidays. Twin scans with Dr Fred Ushakov or Ms Diane Nzelu are £360 plus the £80 supplement. NIPT for twins is always priced together with a scan; all our prices are on the fees page.
Do I still need my NHS scans if I have private twin scans?
Yes. Your NHS twin team provides the full schedule of scans and appointments set out by NICE, free of charge, including scans every 2 weeks from 16 weeks if your twins share a placenta. Private scans can add reassurance or detail between those visits, but they should never replace them. We are always happy to send your report to your NHS team.
Can I have NIPT if I am expecting twins?
Yes, with a test validated for twins. Among our tests, PrenatalSafe and PrenatalSafe Complete Plus are suitable, and Panorama can be used without its microdeletion screen. KNOVA is not suitable for twins. The result applies to the pregnancy as a whole, so a higher-chance result with non-identical twins cannot say which baby is affected. See NIPT in a twin pregnancy above.
What is TTTS and could it affect my twins?
Twin-to-twin transfusion syndrome is an imbalance in blood flow between twins who share a placenta. It affects around 10 to 15 per cent of monochorionic twin pregnancies and cannot occur in twins with separate placentas. It is monitored with scans every 2 weeks from 16 weeks and, if diagnosed, treated at a specialist fetal medicine centre. See our TTTS section for symptoms to report promptly.
One twin is measuring smaller than the other. Should I be worried?
Small differences in size between twins are common. NHS scans compare the babies' estimated weights from 16 weeks if they share a placenta, and from 24 weeks if they have separate placentas.
NICE advises closer monitoring, at least weekly with Doppler checks, if the difference reaches 20 per cent or more or if either baby measures below the 10th centile, and referral to a specialist centre at 25 per cent or more with a baby below the 10th centile. Please discuss any measurement with your NHS twin team, who can interpret it alongside your full history.
Our page on fetal growth restriction explains more.
Can you tell the sex of both babies?
Usually, yes. From our early fetal scan onwards we can often see each baby's sex on ultrasound, depending on the babies' positions. Standard NIPT in twins can show whether at least one baby is likely to be a boy, but it cannot reliably give the sex of each twin.
Do you scan triplets?
Please contact us before booking a triplet pregnancy scan so we can allow enough time. Triplet scans are charged at the standard scan price plus £160 (£80 per additional baby). Triplet pregnancies are not eligible for NIPT.
Why does a twin scan take longer?
Because each baby is examined in full: anatomy, measurements, fluid and, later in pregnancy, blood flow, then compared with the other baby. A twin scan therefore takes around twice as long as a scan of one baby.
Important to know
This information is intended for general educational purposes only and does not constitute medical advice. Please consult a qualified healthcare professional for guidance specific to your individual circumstances. If you have concerns about your pregnancy or your babies' wellbeing, contact your midwife, GP or maternity unit promptly.
Contact
Book a twin pregnancy scan, or ask us first
Sources & clinical references
The figures and clinical statements on this page are drawn from the sources below. Guidance evolves — always discuss your individual circumstances with a clinician.
- NICETwin and triplet pregnancy (NG137): recommendations2019
- NHSAntenatal care with twins2022
- NHSPregnant with twins2022
- GOV.UK (NHS Fetal Anomaly Screening Programme)Fetal anomaly screening programme handbook: screening for Down's syndrome, Edwards' syndrome and Patau's syndrome2025
- Twins TrustWhat is TTTS (twin-to-twin transfusion syndrome)?2026
- Ultrasound in Obstetrics & Gynecology (Judah et al.), via PubMedCell-free DNA testing of maternal blood in screening for trisomies in twin pregnancy: updated cohort study at 10–14 weeks and meta-analysis2021
- Journal of Clinical Medicine (Norwitz et al.), via PubMedValidation of a single-nucleotide polymorphism-based non-invasive prenatal test in twin gestations: determination of zygosity, individual fetal sex, and fetal aneuploidy2019
- npj Genomic Medicine (Villela et al.), via PubMedFetal sex determination in twin pregnancies using non-invasive prenatal testing2019