Our work with researchers

Evaluation of the impact of fibronectin and cervical length monitoring in triplet pregnancies

Dr Lisa Story (St Thomas' Hospital, London)

We don't currently know how best to predict preterm birth in triplet pregnancies. In singletons, doctors might measure the cervix and use swab tests to help determine the chance of preterm delivery. This study will use these existing techniques to see if they also help predict preterm birth in triplet pregnancies. People taking part in this study will have their cervix measured via ultrasound and a swab taken fortnightly between 16 and 32 weeks of pregnancy. We hope this will help doctors to improve their support and guidance for people who are expecting a triplet pregnancy.

This study has been jointly funded by Twins Trust and the British Maternal Fetal Medicine Society.

The role of the vaginal microbiome and cervical length at 16 weeks in the prediction of preterm birth in twin pregnancy

Dr Andrew Sharp (University of Liverpool)

A large proportion of twins are born early, however unlike singletons we don’t exactly know how to predict or prevent these preterm births. This study will look at twin pregnancies early on (at 16 weeks) to see which bacteria, yeasts and proteins from the cervix are found, and whether there is a pattern linking them to a preterm birth later on. If a pattern is shown, this will help us to know who is likely to have a preterm birth in the future, so the doctors and family can be prepared. This could also help us to find treatments for preterm birth.

This study has been jointly funded by Twins Trust and the British Maternal Fetal Medicine Society.

Exploring Novel Techniques for the Prediction of Spontaneous Preterm Birth in Multiple Pregnancies

Dr Brenda F Narice (University of Sheffield)

This study uses a device to measure electrical changes in the cervix (called “bioimpedance spectroscopy”). This is something that already takes place in singleton pregnancies, which helps doctors to understand when labour may begin prematurely. Researchers want to understand if this method also works in twin pregnancies, so doctors can prepare and advise families. It may also help us to work towards a treatment for preterm birth in twins.

This study has been jointly funded by Twins Trust and the British Maternal Fetal Medicine Society.

Quantitative fetal fibronectin, cervical length and vaginal microbiota for the prediction of preterm birth in twin pregnancies undergoing fetal laser surgery

Lindsay M Kindinger (University College London)

Laser surgery, which is usually given for Twin-to-Twin Transfusion Syndrome (TTTS) or Twin Anaemia Polycythemia Sequence (TAPS), often ensures that a baby who would otherwise die from these conditions survives. However, laser surgery also brings a higher risk of preterm birth. This study will look at a number of factors including proteins, bacteria and the length of the cervix, to see if they can help accurately predict who will have their babies prematurely. Understanding this will help improve care for this high-risk group.

This study has been jointly funded by Twins Trust and the British Maternal Fetal Medicine Society. This bursary was awarded in memory of Eva Boyle, a much-missed, forever-loved twin.

Development of a core outcome set (COS) for multiple pregnancy studies: part of the 'COMET' initiative to standardise outcomes collected in research

Dr R. Katie Morris (Birmingham Women's Hospital)

Treatments are developed and tested by researchers to make sure they work and are safe. To do this, researchers need to look at the effects those treatments have on patients. They do this by measuring an 'outcome'. At the moment, different published studies looking at treatments for the same condition often measure different outcomes. When the two studies are finished, we cannot compare or combine their results because they have used different outcomes. 

This study will create a Core Outcome Set for twin research - a standard list of outcomes that studies can use so we can compare the results. This makes research much more useful. Parents, doctors, midwives and nurses have all contributed the outcomes they think are important, and the researchers have also looked at the outcomes from existing studies.

This study has been jointly funded by Twins Trust and the British Maternal Fetal Medicine Society.

Evaluating Risk Antenatally in Twin Pregnancies - A Pilot Study

Prof. Alexander Heazell (University of Manchester)

Twin pregnancies experience more complications than singletons, which can cause long-term health problems, or in some cases, cause the death of a baby. Sometimes we know why this happens, but other times the cause is unknown. A lot of the risk factors that may cause problems have been researched in singletons, not twins. This pilot study looked at twin pregnancies to see if the risk factors are the same or different compared to singletons. It showed that there are probably differences which we need more research to fully understand. You can read more about what the study found.

This study was jointly funded by Twins Trust and the British Maternal Fetal Medicine Society.

Emergency Cerclage in Twin pregnancies at Imminent Risk of Preterm Birth: an Open-Label Randomised Controlled Trial

Prof. Asma Khalil (St George’s Hospital, London)

One of the causes of preterm birth in twins can be a weakened neck of the womb (cervix). There are two main ways to manage a weakened cervix in pregnancy. One option is to do nothing and observe the pregnancy. The other is to strengthen the cervix with a stitch (called a cerclage) to provide extra support. There isn't strong evidence to suggest which of these is better for twin pregnancies.

This trial divided patients with a weakened cervix into two groups - one group was treated with the cerclage stitch, and the other group was monitored but not treated. Researchers then looked at what happened to the pregnancies and compared the two groups to see if one approach was better than the other. They put their findings together with other similar studies, which showed that the rate of preterm birth and health problems may be lower in pregnancies treated with a cerclage, but more research is needed to give strong enough evidence to be sure about this. You can read more about what the researchers found.

This study was jointly funded by Twins Trust and the British Maternal Fetal Medicine Society.

Examining the myometrial transcriptome in twin pregnancy

Dr Andrew Sharp (Liverpool Women's Hospital)

This study has tried to understand whether differences in genetics can explain why some people have their twin babies early (preterm birth). By comparing the genes that are present in people expecting twins to genes from people expecting one baby, it can tell us more about what is happening in the body when a preterm birth occurs. For example, it might tell us about how the extra stretch on the womb caused by carrying two babies may be linked to preterm birth in twins.

The study found that there were very few genes which were different between the two groups. This tells us that we may need to look at other reasons why preterm birth occurs in twins. You can read more about the study.

This study was jointly funded by Twins Trust and the British Maternal Fetal Medicine Society.

A prospective observational study using UKOSS of cases of single twin demise (SIUFD) (>14 weeks) in MC twin pregnancies in the UK, including adverse maternal, fetal and perinatal consequences and prognostic factors

Dr Katie Morris, Prof. Mark Kilby (University of Birmingham) and Prof. Marian Knight (University of Oxford)

Pregnancies where twins share one placenta (monochorionic pregnancy) have a high risk of complications because the babies share blood flow. Sadly, this means that babies sometimes die as a result. If one baby dies towards the second trimester of pregnancy or later, it can affect the other baby and the rest of the pregnancy. To learn more about these risks, doctors worked together with the UK Obstetric Surveillance System (UKOSS) to collect information about twin pregnancies where one baby died and what effect this had on the pregnancy.

The study found a few things, including that:

• monochorionic twin pregnancies where one baby dies are complex and need specialist care
• more research is needed to understand the causes of death, the best time for the surviving baby to be born, and how and when to treat preterm birth
• more doctors need to be aware of the importance of looking at the baby’s central nervous system (the system involving the brain and spinal cord) after a twin dies, to pick up any health problems.

You can read more about the research.

This study was jointly funded by Twins Trust and the British Maternal Fetal Medicine Society.

Twin pregnancies with complications: impact on neurodevelopment study via registry follow up (TWINS-RF)

Prof. Asma Khalil (St George's Hospital, London)

Twins who share a placenta in the womb (monochorionic twins) have a risk of complications including Twin to Twin Transfusion Syndrome (TTTS), Twin Anaemia Polycythemia Sequence (TAPS), Twin Reversed Arterial Perfusion Sequence (TRAPs) and selective growth restriction (sFGR or sIUGR). In rare cases, one baby dies, known as selective intrauterine death. Because the babies are connected by their placenta, a condition that affects one baby usually affects the other as well. As treatments get better, more babies are surviving these complications, but we don't know much about the effect the complications have on them as they grow and develop after they are born. Researchers compared babies who had complications with those who didn't, and studied how they were developing one year after they were born. The study found that babies who had complications continued to experience an effect on their development one year after birth. The researchers recommended that doctors should continue to look for long-term effects in babies who had a complicated monochorionic pregnancy.

You can read more about the study findings.

This study was jointly funded by Twins Trust and the British Maternal Fetal Medicine Society. If you have any concerns about your children’s development, please speak to your health professional.

A retrospective study to determine the prevalence of MCMA twin and triplet (any chorionicity) pregnancies using population-based NorSTAMP and STORK data for 2000-2013, and to compare birth outcomes and clinical management of these pregnancies across the NE and with those from the STORK multiple pregnancy cohort and also before and after the publication of the NICE guidelines

Dr Therese Hannon (Newcastle upon Tyne NHS Foundation Trust)

Monochorionic monoamniotic (MCMA) pregnancies are a rare type of pregnancy where two babies share a placenta and an amniotic sac. To understand more about these pregnancies, researchers looked at existing collections of pregnancy data (NorSTAMP and STORK). They found that 8 out of every 100,000 pregnancies (0.008%) are MCMA twins, and about 1 in 3 of those sadly experienced a pregnancy loss before 24 weeks. This was usually because labour began too early in pregnancy. However, fewer babies from MCMA pregnancies die now than in the past, because doctors can identify them early on, keep track of how the pregnancy is developing, and deliver babies at the safest time, which for MCMA twins is 32-34 weeks of pregnancy. You can read more about the findings.

The researchers also looked at monochorionic triplet pregnancies (where all three babies share one placenta). This showed that these pregnancies had a high risk of stillbirth due to complications like Twin-to-Twin Transfusion Syndrome (TTTS) and selective growth restriction (sFGR or sIUGR). However, once the babies were born, they were as healthy as any other triplet babies. You can find out more about this research.

This study was funded by Twins Trust with support from the British Maternal Fetal Medicine Society.

Working together with Twins Research Australia, St George’s Hospital, London and clinicians from around the world, we wanted to identify the most important research questions for twins, triplets and more, their families, clinicians and researchers. We collected suggestions for research questions from all these groups in our survey, then asked participants to rank which were most important to them, and attend a meeting to agree the top ten priorities.

These top ten research priorities, which were published in the Journal of Ultrasound in Obstetrics & Gynecology, are:

• Would staff with specialist training in multiple pregnancies improve outcomes in these pregnancies?
• How can we reduce multiples’ admission to the neonatal unit? If admitted, how can we reduce multiples’ length of stay in the neonatal unit?
• What interventions prevent and support postnatal mental health problems in parents of multiples?
• How can we prevent maternal complications of multiple pregnancies?
• What are the short- and long-term outcomes in multiple pregnancies? How are these outcomes affected by antenatal events & medical interventions?
• How are higher order multiple pregnancies best managed?
• What are the expected growth patterns of small-for-gestational-age multiples? How can we assess the growth of infant multiples and ensure that they follow a satisfactory growth trajectory?
• What parental interventions can improve the developmental outcomes (ie. speech, language, education) of multiples?
• What are the short- and long-term maternal health risks following a multiple pregnancy?
• What prenatal factors (including changes to lifestyle, health history, personality characteristics etc.) and supports for parents of multiples have the most benefit on birth and ongoing health outcomes for both parents and their children?

Researchers are now using these priorities to shape the future of multiple pregnancy research.

In the past, twin babies have been measured during pregnancy using growth charts designed for one baby, meaning doctors have to decide if they are growing correctly. Because twins are usually smaller than singletons, this means they are more likely to be diagnosed with growth restriction and delivered early, even if there are no other signs of a problem. In 2015 we funded research by doctors at St George's Hospital to develop growth charts based on twin pregnancy data, to see if these would lead to fewer babies being delivered earlier than they need to be. Further research into these charts shows that they may be helpful for telling the difference between twins who are not growing well and have a risk of health problems, and twins who are naturally small but healthy. This would mean that doctors can deliver babies early if they think there is a risk of problems, or continue with the pregnancy if the babies are growing normally for twins.

Different hospitals use different charts to measure twins, so speak to your healthcare professional if you want to know which growth charts your maternity unit are using.

More research on these twin growth charts can be found below:

• The Association Between Hypertension in Pregnancy and Preterm Birth with Fetal Growth Restriction in Singleton and Twin Pregnancy: Use of Twin Versus Singleton Charts
• Perinatal Outcomes of Small for Gestational Age in Twin Pregnancies: Twin vs. Singleton Charts
• Are Twin Pregnancies Complicated by Weight Discordance or Fetal Growth Restriction at Higher Risk of Preeclampsia?