Episode 92: The World's First Standard Maternal and Fetal Adverse Event Terminology

On this week’s episode, Dr. Bahijja discusses preterm prevention and prenatal medicine with Professor Anna David, obstetrician and gynaecologist. Professor David is a professor at UCL, consultant at UCLH, and leader of the UCL Institute for Women’s Health.


A bit about Professor David’s work…

Professor David specialises in obstetrics, looking after women and their babies, and improving their outcomes. At the UCL Institute of Women’s Health, Professor David leads a research team which researches women’s health in great depth, including pregnancy, adolescence, women’s cancer, older age and menopause.


“We concentrate on the whole life course of women’s health” – Professor David

Additionally, they also research men’s reproductive health, an area which is becoming increasingly recognised as very important for pregnancy outcome.


“Recent data has shown that if you are an older dad, you are more likely to have babies with problems such as autism later in life” – Professor David

Foetal surgery

UCLH and UZ Leuven University were commissioned by the NHS to conduct the first foetal surgery service in the UK. Professor David’s team repairs spina bifida defects, where the vertebral column does not develop correctly in the womb, causing a gap in the spine where nerves can herniate and become damaged. However, repairing this defect before birth improves the outcome, and following their successful surgeries, they have since been commissioned for 18 months to offer foetal surgery as a service across the UK, successfully operating on about 30 women.



The earliest time spina bifida is detected is around 12 weeks, when it can be visually seen in the foetus through ultrasound scans. However, operating at around 20-26 weeks has been shown to be the best time – any later would reduce the extent to which the condition could be improved. Operating too early could increase the chance of the membranes surrounding the foetus to be damaged, causing the leaking of the contained fluid and inducing early labour.


“One of the problems with doing foetal surgery is that you’re making a hole in the womb, and that hole never really seals up” – Professor David

The technique that Professor David’s team uses is open foetal surgery – this involves making a small cut across the womb, and the defect to be corrected directly. However, they are currently looking into foetoscopic techniques, and whether they could be as successful as open foetal surgery. Foetoscopic surgery involves inserting 3 very small ports into the womb, and operating down the end of a telescope, however it is still very experimental and is currently undergoing a lot of research to determine how safe and effective it is.


Professor David’s journey and experiences

“I think I always enjoyed learning about development” – Professor David

During medical school, Professor David enjoyed learning about pregnancy and found it to be an amazing concept, comprising a combination of both medicine and surgery.

“It’s never boring, there are some really interesting ethical dilemmas that happen, but also it’s very exciting” – Professor David

Professor David currently sees a lot of women who have high risk pregnancies, such as those who have very small babies that isn’t growing very well in the womb – this is called foetal growth restriction. Sometimes the baby is growing so slowly that it is uncertain as to whether they will ever reach a weight where they can be delivered.




One of the areas that Professor David is working on includes developing a treatment to try to improve growth in the womb before the baby is born, and Professor David’s team is now able to predict what will happen through following scans over 1-2 weeks. In around 1/3 of cases, the baby will not survive, and in the other 2/3 of cases, the baby could still be able to grow. However, this presents a dilemma where a difficult conversation must be had with the mother in deciding whether or not it is worth it to go through with the pregnancy.


What are the challenges of conducting clinical trials in this area?

“People are terrified of giving any kind of intervention in pregnancy” – Professor David

Professor David highlights how those within the 18-40 age range who are the least likely to have been vaccinated are pregnant women. It is now known that the COVID-19 vaccination is safe during pregnancy, however, it was initially never trialled in pregnant women – trials are only just being conducted at UCLH.


Professor David’s team have recently been working on a way to assess safety in clinical trials. As there are no drug trials during pregnancy, there is no setup to conduct clinical trials in general for pregnant women.

“Nobody ever designed a system to assess adverse events in the foetus” – Professor David

Professor David’s team developed the first terminology to collect up safety data for the mother and foetus – the lack of this vocabulary had previously presented a huge barrier to conducting clinical trials during pregnancy. The team developed MFAET – Maternal Foetal Adverse Event Terminology, a universal consensus about what’s important, what the adverse events are and how they are graded.


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