Intervention or Expectant Management for Early Onset Selective Fetal Growth Restriction in Monochorionic Twin Pregnancy 

FERN is a UK study taking place in multiple hospitals to look at selective fetal growth restriction (sFGR also known as sIUGR) in monochorionic twin pregnancies (where both babies share one placenta) depending on whether they had an intervention or were monitored without any other treatment. The study wants to find out when sFGR occurs, who it affects, and what the impact is on the pregnancy.

Monochorionic twin pregnancies which develop sFGR can lead to poor outcomes for the babies. There is currently a lack of evidence to guide doctors as to how they should treat this condition, especially for sFGR which begins before 24 weeks of pregnancy.

The FERN study wants to see if it’s possible to conduct a trial comparing different treatments with monitoring the pregnancy without treatment in monochorionic twins who are diagnosed with sFGR. It will also take into account parents’ preferences, doctors’ preferences, ethical dilemmas, current UK practice, the number of cases per year, what we already know about sFGR and what would be needed to design a new trial.

Growth Restriction

This study has three parts:

Work Package 1 (WP1)

WP1 uses experiences from a recent survey of current practice and the TTTS registry to collect data on the management and clinical outcomes of monochorionic twin pregnancies with sFGR. The study includes 120 women with a monochorionic twin pregnancy with sFGR identified before 24 weeks of pregnancy, from 21 UK Fetal Medicine Units. The study team are looking at what doctors currently do when they are treating these pregnancies, and what impact this has on the babies. This will help us to learn about how and when sFGR develops, what treatments are currently being used, and what happens to the pregnancy following treatment.

Work Package 2 (WP2)

WP2 involves interviews and focus groups with 25 parents and 25 doctors, to get their views on the proposed trial, including any ethical concerns and concerns about the design of the trial. This information will be used to inform Work Package 3 (WP3).

Work Package 3

WP3 will use the information from work packages 1 and 2 to decide how and if to run the trial. The study team will use a process called Delphi methodology which involves parents, doctors, funders and relevant charities to make decisions about how the trial should be run.  If the result is to go ahead with the trial, the study team will then be able to design the trial and seek funding to do further research into the best way to manage a monochorionic twin pregnancy with sFGR.

This study is being run by Professor Asma Khalil through the Harris Wellbeing of Women Research Centre at the University of Liverpool, and is funded by the National Institute for Health Research (NIHR) Health Technology Assessment (HTA).

For more information you can contact the FERN Study Management Team:
Email: [email protected]
Tel: 0151 795 9562

For further information on the findings of the FERN study, please see the publications below:

• Diagnosis and management of selective fetal growth restriction in monochorionic twin pregnancies: A cross-sectional international survey
• Balancing key stakeholder priorities and ethical principles to design a trial comparing intervention or expectant management for early-onset selective fetal growth restriction in monochorionic twin pregnancy
• Is it possible to conduct a randomised controlled trial of intervention or expectant management for early-onset selective fetal growth restriction in monochorionic twin pregnancy? - Protocol for a prospective multicentre mixed-methods feasibility study
• Ethical considerations of a randomised controlled trial of fetal intervention versus expectant management in monochorionic twin pregnancies with early-onset selective fetal growth restriction