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

The association between triplet pregnancies and premature birth is well-established: one third deliver before 32 weeks of pregnancy. Premature birth can be associated with significant developmental problems as well as breathing difficulties for the babies.

In order to obtain the best outcomes, triplets should be delivered in a specialist obstetric/neonatal unit.  Clinicians therefore face the question of when to transfer the pregnancy to the specialist hospital and whether to give treatments such as steroids to improve the baby’s lung growth, which are time sensitive.  Over-treatment also has significant cost implications for health services.

There isn’t currently enough knowledge about the best time to deliver and how to monitor for the risk of preterm birth in triplet pregnancies. This is in contrast to twin pregnancies, where measuring the length of the cervix and using swab tests (such as fetal fibronectin, a substance found in the vagina known to increase in women who deliver early), and decision aids to determine when a woman is likely to deliver, are more commonly used to plan care. For example, doctors use these tools to plan admission to hospital and timing of steroids which help to mature the babies’ lungs if delivery is thought to be imminent.

In this study, researchers are going to take measurements of the cervix (using ultrasound) and swab tests measuring fibronectin fortnightly from 16 weeks to 32 weeks in 60 women with triplet pregnancies. They will use the QUIPP app (currently used in twin pregnancies) as a guide for prediction of preterm labour in next 1, 2, 4 weeks, and prior to 30 weeks.  The study will be based in three inner London tertiary fetal medicine units that run dedicated multiple pregnancy and preterm surveillance clinic services.

Researchers hope that this study will help to assess how useful measuring cervical length and fibronectin is in guiding management and decision making in women with triplet pregnancies.

This study is being carried out by Dr Lisa Story at St Thomas’ Hospital, and was funded by the Twins Trust and BMFMS research bursaries. Read more about the studies we have funded here: https://twinstrust.org/who-we-are/what-we-do/research/research-bursaries.html