Researcher Spotlight: Dr Rachel Freathy

Dr Rachel Freathy is a Wellcome Trust/Royal Society Sir Henry Dale Fellow at the University of Exeter. Her research focuses on the birth weight of babies and what factors during pregnancy may influence a baby’s growth. Here she explains her research methods and explains why talking about her work is important…

What are you working on?

I am trying to find out which characteristics of pregnant women influence the birth weight of their babies. We know that women who are overweight or have diabetes in pregnancy tend to have bigger babies. But there are many metabolic changes associated with obesity or diabetes in pregnancy, and we do not know which of these are actually causing the baby to grow bigger. Is it just higher glucose levels? Or are there higher levels of other dietary nutrients such as lipids increasing the growth of the baby when a mother is overweight.

We are attempting to cut through this complexity using genetics. The technique is called “Mendelian randomisation”. For example, instead of measuring the variation between glucose levels in different women, we can now measure variation in the genes known to influence their glucose levels.

This “genetic glucose measurement” is useful because unlike a mother’s circulating glucose, it is not associated with other characteristics such as her diet or lifestyle because her genes do not change. Comparing the birth weights of babies born to women with different genetic measurements of glucose is therefore like performing a randomised controlled trial.

We are applying this method to test several maternal characteristics for causal effects on the growth of the baby.

What does your average day involve?

A large part is spent at my desk analysing data, writing and preparing papers or talks, talking to or emailing colleagues, or on teleconferences. The teleconferences and email communication have become extremely important in my field because we work together in large, multi-national consortia, meta-analysing data from many individual studies to maximise our power to detect true genetic associations.

Why is your work important?

Babies born with extremely high or low birth weights are at considerable risk of illness or even death. We know very little about what causes some babies to be born very large or very small. If we can use genetics to work out which maternal characteristics are increasing or reducing the growth of a baby, then there is potential to focus care in pregnancy on these characteristics to maximise the number of healthy weight babies.

What do you hope the impact of your work will be?

I believe that our work will provide a better understanding of the factors affecting fetal growth. I hope we can identify with confidence the maternal characteristics that should be the focus of clinical trials of safe treatments/interventions aimed at reducing the number of very high or very low birth weight babies.

Just as importantly, I hope our work will identify which maternal characteristics are unlikely to influence birth weight and therefore should not be the target of further research.

How did you come to be working on this topic/in this field?

I completed a PhD on the genetics of type 2 diabetes with Professors Andrew Hattersley and Tim Frayling at the University of Exeter. During my PhD, I became interested in the links between type 2 diabetes and birth weight, and I was also lucky enough to take part in the analyses of the first genome-wide association studies of type 2 diabetes. These studies gave me valuable experience and skills, which I have taken forward into studies of birth weight.

How has Wellcome funding helped you/your research/your career?

Enormously! After my PhD, I was awarded a Sir Henry Wellcome Postdoctoral Fellowship, which gave me amazing opportunities to work with and learn from world-leading scientists in Exeter, Bristol and Chicago.

In the last few years, I have greatly appreciated the flexibility and support offered by the Wellcome Trust in regard to maternity leave and part-time working. I had two babies during my Henry Wellcome Fellowship – my very own birth weight experiments – and I’m pleased to say that they are doing well and keeping me very busy. I am now the delighted recipient of a Sir Henry Dale Fellowship to support building my own research team here in Exeter.

What’s the most frequently asked question about your work?

From non-scientist friends and family: “Any exciting developments?” – followed by: “What does that mean?”

Which question about your work do you most dread – and why?

There aren’t any in particular. I have had plenty of difficult questions, but in hindsight, they have usually been the most helpful as they have challenged me to improve my research and/or communication skills.

Tell us something about you that might surprise us…

As a biological sciences undergraduate, I studied almost no human genetics. I was really interested in entomology (I was taught and inspired by Dr George McGavin, who is now often on TV) and animal behaviour (my undergraduate project was on the mating tactics of sexually competing male guppies).

I still find these subjects fascinating and love teaching my children about them, but nowadays it’s the thought of making a contribution to improving human health that really motivates me.

What keeps you awake at night?

At the moment, it’s my two-year-old daughter, Eliza. She still hasn’t quite got the hang of sleeping all night. Last night she serenaded us with “Let it go” from Disney’s Frozen, which is a great song, but not so welcome at 3am.

What’s the best piece of advice you’ve been given?

“Keep talking to people about your work.”

I have often been impressed by how quickly problems can be solved or by how new ideas can emerge when I talk to others, either formally or informally. In my area of genetics, some truly amazing things have been achieved in recent years through large-scale collaborations, which began with conversations.

The chain reaction question set by our previous spotlit researcher Dr Mark Thompson is: If you had not become a scientist, what career would you have chosen?

I spent four years as a secondary school science teacher before becoming a scientist, so there’s an empirical answer to the question. I left because I missed having time to study my subject in depth, but I enjoyed teaching and learned a great deal from the experience. If I had to choose something different again, I might be an obstetrician or a music therapist. 

You can find out more about Dr Freathy’s work via her University of Exeter profile page and follow her on Twitter. You may also be interested to read her paper: New loci associated with birth weight identify genetic links between intrauterine growth and adult height and metabolism, published in Nature Genetics.