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Friday 20 March 2020

Caesareans (Things We Don’t Know about Pregnancy Series #15)

Historically, a caesarean section was a life or death operation. When a birth started to go wrong, the question was who to save – the mother, or the baby? Luckily, the maternal mortality rate for pregnancy has dropped to around 0.007% in the UK in 2017 (down from 0.09% in just 1952[1]), and caesarean sections are now considered only slightly more risky than vaginal births (death risk is 3 times higher[2], but this may be because a number of caesareans are only carried out in emergencies). Caesareans may also reduce the risk of complications in some cases. It used to be that having a caesarean once meant further babies always had to be delivered this way – but that’s no longer true: for women who have previously had a caesarean section, choosing an elective one for a subsequent baby over a vaginal birth reduces the risk of complications or consequential health problems (such as womb damage) from 1.8% to 0.8%[3]. However, risk overall is small.

Caesareans now account for 26.2% of births in the UK[4], but there is still a lot we don’t know about them, especially how they might affect babies later in life.

Caesarean by Salim Fadhley via Wikipedia Commons.

Saturday 14 March 2020

Climate change, glacial recession and mammal communities

By now, we are probably all familiar with the alarming fact that the polar ice caps are melting, and we’ve probably all seen the pictures of starving, stranded polar bears on thin pieces of sea ice. Scientists often look to the cryosphere – or the frozen water part of the Earth, such as ice caps, glaciers, areas of snow, and ice shelves – to understand the progression of climate change and predict how things may change in the future.

Changing climates have impacted the cryosphere for millions of years, and massive ice sheets have repeatedly advanced and retreated throughout history. The recession and advancement of these walls of ice has had an enormous impact on landscapes and the distribution of species, and while there have been many studies investigating how historical glacial recession has impacted current species distribution, little is known about how current species distribution is impacted by present day glacial recession.

Example of a tidewater glacier in Glacier Bay National Park. Johns Hopkins Glacier. ©