TTTS is a potentially fatal disease affecting twins that share a placenta, where one twin transfuses blood to another.  Left untreated most babies die. There has been too little research looking at the most effective treatments for TTTS in the short or longer term. 

To address this need, in 2015 we funded St George’s Hospital and other fetal medicine centres to set up the first UK TTTS Registry, to collect data on all pregnancies affected by TTTS. This would enable long-term follow up of TTTS survivors at a national level and help identify how care and treatment for these pregnancies can be improved.

Since then the Registry has been expanded to include data from all complicated multiple pregnancies, and uncomplicated triplet and monochorionic twin pregnancies, to extend the benefits of the Registry beyond TTTS.

There are many gaps in medical knowledge, where there are uncertainties about the best treatment to offer in pregnancies which develop complications, and about the best way to monitor for the development of these complications. This registry will ultimately help answer these important questions, which will help improve the care of women with a twin or triplet pregnancy and their babies. It will also provide a platform to allow long-term follow-up of these children at a national level and to ensure that women with multiple pregnancies in the UK receive consistent, evidence-based care.

Already three studies are using this data to examine the best treatments for different complications, which are:

• a long term follow-up of neurodevelopmental outcomes for pregnancies affected by TTTS, single intrauterine death, selective intrauterine growth restriction, twin reversed arterial perfusion sequence (TRAPS) and twin anaemia polycythaemia sequence (TAPS) 
• a trial to examine whether emergency cerclage is effective in twin pregnancies at imminent risk of preterm birth.
• a study to determine the most effective way of managing and treating pregnancies with selective fetal growth restriction. 

In November 2018, the Registry was accepted onto the National Institute for Health Research (NIHR) clinical research network portfolio, which means that participating centres can access local support and reimbursement for each case they upload. As a result, there has been a high level of interest from new centres. New centres receive training and support to correctly upload data about the pregnancies they see which will then be used in future studies to improve the way these pregnancies are managed.