As with all mothers-to-be, a twin or more pregnancy is divided into three phases of about three months each, known as the first, second and third trimesters. 

You will find information about your multiple pregnancy in the sections below. Our Care Checklist covers the level of care you should be offered from the time of your first hospital scan, in addition to the routine care that is offered to all women during pregnancy. It aims to reduce risks and improve outcomes for you and your babies. We also have a list of twin clinics, to ensure you're getting the best possible maternity support.   

Scans for an expectant mother of multiples


There are different types of multiple pregnancy so each care pathway is slightly different.

Twins can be dichorionic (they have separate placentas) or monochorionic (they share a placenta).

Triplets have a few possible combinations:

Trichorionic – each baby has a separate placenta

Dichorionic – two of the babies share a placenta and the third baby is separate

Monochorionic – all three babies share a placenta

It is possible for twins and triplets to share an amniotic sac as well as a placenta, Monochorionic/Monoamniotic. Although rare, these pregnancies need extra care, closer monitoring by a specialist and an individual care pathway which will include scanning every 2 weeks after 16 weeks gestation. For twins, an earlier birth is recommended between 32-34 weeks. For triplets, the timing of birth will be decided and discussed with you individually and you may also be referred to a different hospital that has more experience of triplet pregnancies

Twin Pregnancy 

Dichorionic / Diamniotic

(Two placentas, two sacs)

Monochorionic / Diamniotic

(One placenta, two sacs)

Triplet Pregnancy

Trichorionic / Triamniotic

(Three placentas, three sacs)

Dichorionic/Triamniotic & Monochorionic/Triamniotic

(Two placentas, three sacs & one placenta, three sacs)

The first ultrasound scan usually takes place at the end of the first trimester, at around 11-14 weeks’ gestation. This will confirm the number of foetuses and whether they are in separate or shared amniotic sacs. If the babies share an amniotic sac they are certain to be identical. But sometimes identical twins have one sac each, so the presence of two amniotic sacs does not rule out your babies being identical. The sonographer will also check to see if the babies share a placenta (monochorionic), which can lead to complications. Sometimes this is hard to see, but if it appears to be the case then your obstetric team will want to scan the babies regularly to make sure they continue growing well.

All pregnant mothers are given an anomaly scan at 18-22 weeks to check the babies are developing normally. Mothers of multiples not only get an anomaly scan but will be scanned throughout their pregnancy to check on their babies’ growth and positioning. The timing and frequency of these scans varies according to the number of babies, their chorionicity (whether they share a placenta), hospital procedure, and whether anything else needs monitoring.

Ask if the hospital has a midwife or doctor who specialises in twin or more births and try to arrange your antenatal appointments with them.

You may have a list of questions. Don’t feel rushed at your appointments: if you need extra time to work through your list, ask for it. You may want to know, for example, what the hospital procedure is for twin births and what special arrangements there are for antenatal care in twin or more pregnancies. It may also be useful to find out if the hospital has a midwife who specialises in breastfeeding support for mothers of multiples. Make sure you mention any symptoms you are having, even if you think they are probably normal. The doctor or midwife can put your mind at rest or investigate further if need be.

If you are unhappy with your hospital care, ask to speak to another doctor or midwife. All hospitals have a complaints procedure. You can also contact us at Twins Trust for help and support. Antenatal classes are especially important in twin or more pregnancy. As twins or more often arrive a little early, it’s best to ask about and book antenatal classes now to make sure you complete them before the babies arrive – with twins, try to complete the course by the 34th week of pregnancy; for triplets, by the 30th week. Some hospitals have special antenatal classes for multiple pregnancies. Twins Trust runs antenatal courses solely for multiple mums and dads where you can meet other parents who are pregnant with twins, triplets or more. Parents who have attended tell us both the classes and the opportunity to share experiences with others in the same boat are enormously helpful.

With twins, the health team will check the position of the leading baby at about 34 weeks to decide how they should be delivered.

You will be offered some screening tests during pregnancy to try to find any health problems that could affect you or your babies, such as, infectious diseases, Edwards', Down's or Patau's syndrome, or physical abnormalities.

The tests can help you make choices about care or treatment during your pregnancy or after your babies are born.

The sonographer can take measurements during the routine scan at 10-14 weeks to assess the babies’ chances of having Down’s syndrome.

If you sign up for our Free Twins Trust Pregnancy Countdown Tool the combined test and screening is discussed in week 10. Don't worry if you are past week 10 as this will still be available for you to read after you have signed up.

You can also find out more information on screening on the NHS website

It is important to read up on screening and write down any questions you may have so you can ask your consultant and midwife. This will help you make decisions that work best for you and your family.

Whether your babies are identical or non-identical and whether they share a placenta or not, is very important in understanding your options.

Making that decision can be difficult. You may like to speak with your hospital screening midwife or ARC antenatal results and choices.

More information can be found on The Healthy Multiple Pregnancy guide on the Twins Trust website.

There are also non-invasive DNA tests for Downs Syndrome, Edwards syndrome and Patau’s syndrome, often branded as the Harmony test (or NIFTY/SAFE test) available from 10 weeks. These are mainly available in the private sector as they are not yet widely available in NHS hospitals although some are participating in research.

NICE Quality standard 46 sets out the care you should receive during and the timing of appointments and scans depending on the type of multiple pregnancy you have.  NICE Guidelines 137 has additional information for you too.

To help make sure the correct care is given at the correct time during pregnancy, we have created a Care Checklist that details what should be happening throughout your pregnancy which you can print out and take to your appointments. This care checklist covers the level of care you should be offered from the time of your first hospital scan, in addition to the routine care that is offered to all women during pregnancy. It aims to reduce risks and improve outcomes for you and your babies.

Register as a free user, or if you are already registered sign-in, to access our Multiple Pregnancy Care Checklist download.


You should be seen in a dedicated twins/multiples clinic by a specialist team, who have more knowledge about multiple pregnancies, all the time. This would include a midwife, sonographer and doctor. This pathway is based on national best practice and hospitals receive extra funding to look after multiple pregnancies.

If you arrive at the hospital in labour you should be seen by a senior obstetrician with an expertise in twins/multiples who should produce a clear plan for your babies birth, including monitoring the babies and how they will be born.

If you are not receiving the care you would expect please raise it with the PALS team (patient liaison) at your hospital and let us know – [email protected]. We can then liaise with the hospital regarding the correct level of care that should be offered.

Feel free to share this with your midwifery team and use it as a checklist for each appointment.