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Tuesday 28 April 2020

Depression During and After Pregnancy (Things We Don’t Know about Pregnancy Series #18)

Postnatal depression is thought to occur in ~1 in 10 mothers, making it a common form of mental illness. The onset and peak of the illness may be weeks or even months after the birth of a baby, and the condition lasts for weeks, months, or longer.


The condition is characterised by persistent negative feelings – towards yourself, your baby, and things you previously had an interest in. Most parents find their inability to bond to their baby most upsetting, and many feel guilty, hopeless, and even suicidal. Physical symptoms include disturbed sleep, tiredness, increased or decreased appetite, and difficulty decision-making.

We don’t know what causes postnatal depression

We don’t know what causes postnatal depression, although it’s associated with hormonal changes, such as a drop in one hormone called allopregnanolone. But these alone can’t explain everything. Women go through huge and varied hormonal changes during pregnancy and early motherhood, and postnatal depression doesn’t effect everyone. In fact, for a long time, people believed that pregnancy hormones were protective against depression, and it was simply something new mothers couldn’t get – leading to many undiagnosed sufferers[1].

Worried Woman Image credit: RyanMcGuire (CC0 Public Domain via Pixabay)

Monday 20 April 2020

New site feature - follow the story

We are very happy to announce a new feature that has been rolled out across the Things We Don't Know website - automated links to other science websites to help you follow the story behind the research that interests you most.

Our objective here at TWDK is to help people follow the story behind ongoing research into specific scientific topics. We describe the background, and then help you to find news and updates about that research from other sources. Until now, these updates have relied on scientists using our site posting an update manually, or our staff doing so. But now we have started to automatically check a number of sites to see if they've posted anything that is related to our articles. For example, you will now find at the bottom of our article about unanswered questions in artificial intelligence something like this:

Snapshot of "recent science news" related to artificial intelligence from the TWDK website
Snapshot of "recent news" items at the bottom of our article on unanswered questions in artificial intelligence

If you happen to have subscribed to the article, then these links will also appear in your customised feed on the TWDK homepage.

We will gradually increase the number of sites we check for science news that matches our articles, but to begin with we're automatically creating links to articles from the following sites:

We don't import or copy any material from any of these sites - we just add a link from our article to theirs.

These seventeen sites were selected to present a broad range of scientific updates from reputable sources. If you've got a site and you'd like us to add it to our list, just let us know in a comment below.


This guest article was written by Maxwell Holle from the University of Illinois.

A simple glass of milk holds the potential to become hundreds of different types of cheeses with a variety of different flavours. But with so many diverse flavours and styles, how can we identify an off-flavour?

Image by corinnabarbara from Pixabay.


What is cheese?

Cheese is milk that we force into a gel by either acid, heat, or enzymes. While making cheese, we try to remove as much water as possible, which also means losing some milk proteins. The simplest cheeses stop here and are known as fresh cheeses; they have a relatively salty and neutral taste. However, most cheeses take on their characteristic flavours and smells during the ageing and ripening stage, where diverse groups of microorganisms get involved. These microorganisms generate the characteristic flavours of some of our favourite cheeses.

Wednesday 15 April 2020

Birth trauma (Things We Don’t Know about Pregnancy Series #17)

PTSD (post-traumatic stress disorder) is still a condition associated with soldiers. Men. But every year, estimates suggest 4% of births cause maternal PTSD [1]. We call this birth trauma.

Birth trauma was first recognised in the 1990s, when the American Psychiatry Association modified its definition of a traumatic event. It’s now thought that it may affect fathers who were present at the birth as well as mothers.

I recently visited the Oxford Spires – a midwife-led unit where mothers with no complications can give birth in a relaxed environment. It sits conveniently a few floors above the main hospital, so emergency treatment is only a lift journey away. But amongst the pools and mood lighting, the giant squashy birth aid balls and the ergonomic beds, I was struck by how much could go wrong during birth.

And I don’t just mean physically.

Obstetric forceps. Killian 1842 via Wikipedia Commons.

Thursday 2 April 2020

How much do unborn babies sleep? (Things We Don’t Know about Pregnancy Series #16)

We can’t measure the brain activity of a human foetus – not whilst they’re inside their mother. But we’re really interested. What happens to a baby’s brain as it’s developing, and what does this tell us about our own and the developing process of sleep?

EEG (electroencephalogram) reading via Wikipedia Commons.
Researchers into brain activity have performed EEG (electroencephogram) exams on premature babies, and monitored eye movement in the womb to learn about sleep cycles, although big errors with these kinds of measurements are common. They have, however, detected REM (rapid eye movement) sleep from around 7 months, when the brain cycles in and out of restful and REM (rapid eye movement) sleep every 20 to 40 minutes. From 7 months onwards, foetuses mostly sleep (90-95% of the time at 32 weeks, 85-90% by 37 weeks). After it develops, REM sleep increases and increases, reaching a lifetime high of 12 hours a day just before the baby is born.

Very little is known about foetus sleep before this. For example, we don’t know if sleep and sleep cycles suddenly or more gradually develop with the foetal brain. New research into lambs has shown that foetuses enter a dreaming-like brain state weeks before REM sleep starts[1]. As well as learning more about sleep, this study could help us figure out how the brain develops and when it is most at risk.

Equally, neurons in the brain develop much earlier, with those responsible for sleep present long before REM sleep is seen.