Science Lessons with Dr Sarah
Lesson 1: Good Science Takes Time!
You know that terrible time of year when you have to reconcile all the cheques, internet transfers and cash payments you've made in the past financial year with the bills that are stacked in the folder that says ‘tax' in your filing cabinet?
It's mind-frying, time-consuming and mightily confusing even on a good day.
Now imagine that instead of grappling with 200 or so financial records, your task involves over 300, 000 data points which relate to real people. The subject matter is very sensitive: you must sort through information relating to fertility treatments, births and birth defects in South Australia. Maintaining absolute anonymity of all those involved is of upmost importance: so important in fact that it has been prescribed by an ethics committee that you as a study leader are restricted in your access to the data. Hence, you cannot actually see any personal information. Instead, the entire system operates with the use of data identifiers. Each birth record has a number.
Each birth resulting from assisted reproductive technology (ART) has a number. Each occurrence of a birth defect has a number.
With all that in mind, then you must create groups of data by matching numbers. Match each ART number with a birth record number. Match each birth defect number with a birth record number, and hence a mode of conception (ART versus naturally conceived). Then try and make sense of the data by working out whether birth defects are more common in the group of ART births versus the group of naturally conceived births.
It's an enormous, complicated task. It's number crunching at its most extreme. But this is exactly what The Robinson Institute's Michael Davies did recently in his study Reproductive Technologies and the Risk of Birth Defects. Time for the lab coats.
Balancing this delicate project with other more routine tasks - like preparing grant applications, delivering lectures, and meeting with students - meant that Michael and his Adelaide colleagues took the best part of 7 years to collect, de-identify, match, and analyse the required data and then present it to one of the most well-respected medical journals in the world. The paper was accepted for publication and published in the New England Journal of Medicine in May 2012.
But why did they do it? Was this enormous investment of time and effort a worthwhile task?
Well, yes. Because Michael and his colleagues believe that analysing whether reproductive technologies impact on birth defects should be part of the equation when women, couples, families, medical practitioners, governments and society at large think through the pros and cons of ART.
But what did the data tell them? Even when such large analyses are performed, the answers aren't always as clear-cut as one would like. However it does appear from this study, though the story is very complex and at an early stage, that the use of ART to achieve a pregnancy is linked with a somewhat increased risk of a birth defect.
In naturally conceived pregnancies, in every 100 births there are approximately 6 children with birth defects. In every 100 children conceived using ART, approximately 8-10 have birth defects. This slightly elevated risk may have some origin in factors related to infertility, but some could be due to the use of ART itself. More studies are required to further explore the basis of this difference.
Statistically speaking, the absolute number of birth defects is low in both naturally conceived and ART-assisted pregnancies. However from a practical perspective the costs to the affected individual, their family and their immediate and broader communities can be extreme. For this reasons, Michael believes this this data will contribute to important, ongoing discussions about ART, saying
"An ideal situation is to use as little invasive and expensive technology as necessary to achieve a healthy and happy family. This involves an increasingly complex balance of risks, benefits and costs - not just for the patient and clinician, but for the community who in Australia pays for a large proportion of the treatment cost and the bulk of the cost for uncommon but catastrophically expensive adverse outcomes. I trust this study will inform this important debate."
Take home message? Good science takes time.