Determining the Sex of a Baby (Things We Don’t Know about Pregnancy Series #12)

“And do you know… what it is?” they ask.

They mean the sex of our unborn baby, of course.

There isn’t much you can find out about who your unborn baby is, but you can know their sex. Or can you?

Often misnamed as “gender”, sex primarily relates to the organs a person presents with, but we already know that it’s more complex than that.

Chromosomes via Wikipedia Commons.

For a long time, we believed that sex was determined by a single chromosomal pair: XX or XY, but recent research has shown that the expressions of a bunch load of other genes is important too. For example, genes known as “enhancers” regulate the expression of genes that drive the development of physical sex characteristics. This means you can develop testes if you have an extra copy of the enhancers, even if you have two X chromosomes, or develop ovaries if you’re missing them, even if you are XY. The enhancers were found amongst the set of DNA formally known as “junk DNA”. These findings imply that observed biological sex and genetic sex may actually be different in some cases.

Adipogenesis – the making of fat

How Are Fat Cells Formed?

Our entire bodies originate from a single cell. Once it starts dividing, it kick-starts a multiplication process that lasts our whole lives. This ‘starter’ cell is a stem cell; a biologically programmable template for any other cell. They are responsible for everything, including our hearts, minds and waistlines.

Wait, waistlines?

Yes, this is determined by adipocytes, or white fat cells, in a process known as adipogenesis. There are six roughly defined phases of adipogenesis, but within them are a multitude of molecular processes, and explaining how they work poses a considerable challenge to scientists.

Fat, by Bigplankton via Wikipedia Commons.

Silent Miscarriage (Things We Don’t Know about Pregnancy Series #11)

Miscarriage is a common medical complication that leads to the loss of a pregnancy before 23 weeks, and affects one in four women during their reproductive lifetime. Depending on how early or late it happens, it can have bigger or smaller impacts on a woman’s physical and mental health.

But why does it happen? Is it mostly to do with lifestyle, or genetics? Is there something you can do to prevent it? And how can we get early warnings of silent miscarriages – the ones you never even knew had happened?

If you’ve ever been pregnant – miscarriage or not – you’ll probably have wondered about these things, and worried about them, as I have. Whilst the chance of miscarriage drops off rapidly with time, stillbirth and postnatal foetal death are still classed as late pregnancy losses, and do happen from time to time, meaning there is no good time to truly forget about it.

Chances of miscarriage drop as pregnancy progresses. © TWDK. Data from: datayze.com

The Thalidomide Scandal (Things We Don’t Know about Pregnancy Series #10)

In 1953, a new drug was made, and by 1957 it was on the market. In the six years that followed, over 10,000 children in 46 countries were born with congenital deformities^[1]. The disaster was known as the thalidomide scandal, and led to serious reforms in drug regulation and monitoring worldwide.

What happened?

Thalidomide was prescribed for insomnia, anxiety, asthma, hypertension, migraine, and morning sickness. Doctors thought that it was very safe because taking an overdose simply cast the drinker into a prolonged sleep – and did not cause death. It was also non-addictive. Nobody tested it in pregnant women or animals.

Then, in 1961, two doctors independently called out statistically high numbers of congenital abnormalities in “thalidomide babies” – 20% where the normal rate is 1.5% (or a bit higher, depending on your source)^[2].

Thalidomide babies. Image via Wikipedia Commons.