Obviously I have never been pregnant. However I have studied pregnancy in great detail and I have many years of experience looking after pregnant women.

As anyone who has been pregnant will tell you, it is quite different to – er – not being pregnant.

The physiological changes of pregnancy.

Most people don’t realise how dramatically your physiology changes when you become pregnant – and these dramatic changes occur well before people can tell that you are pregnant.

  • From quite early on in their pregnancies, most women tell me that:
  • They feel exhausted,
  • Their exercise tolerance diminishes rapidly – sometimes even a flight of stairs is hard work,
  • They are aware of their heart beating in their chest, and
  • They are going to the toilet to pass urine very frequently.

These symptoms are due to the cardiovascular and fluid changes that occur from very early on in pregnancy. These physiological changes are:

  1. Increased blood volume. A 70 kg non pregnant person has a blood volume of around five litres. As soon as you are pregnant your blood voume begins to increase such that by the time you give birth your blood volume may be as high a eight litres – a 60 percent increase!
  2. Increased cardiac output. This is the amount of blood that your heart pumps out per minute. Our normal non pregnant cardiac output is five litres per minute and – again – this increases by up to 60 percent to seven to eight litres of blood per minute. Your heart achieves this by increasing the number of beats it makes per minute. A normal fit healthy non pregnant woman will have a pulse rate of around 70 beats per minute (or less if she is and athlete). Most pregnant women have a pulse rate of around 90 beats per minute.
  3. Increased total body fluid. In addition to their blood volume pregnant women carry more fluid in their tissues than when they are not pregnant (this is one of the reasons most women suffer from swollen ankles and legs in late pregnancy).
  4. Increased renal (kidney) output. It is hardly surprising that with all of this fluid on board – and with the heart pumping a bit harder – that a lot more blood is flowing through a pregnant woman’s kidneys. This of course is why you seem to get up to go to the toilet twenty times each night when you are pregnant.
  5. Increased blood flow to everywhere. All of this increased blood and blood flow affects all of your organs, including your largest – your skin. The blood flow you your skin increases greatly (this is why some people say women “glow” when they are pregnant). This enables your skin to function as a heat exchange system (because pregnant women – er – have a bun in the oven).
  6. Increased work of breathing.
  7. Lower blood pressure. You would think that with all of this increased blood, fluid and cardiac workload going on your blood pressure would increase when you are pregnant. And yet, if anything, the opposite occurs. Most (not all) pregnant women have their blood pressure fall through the early and middle part of pregnancy before returning to more usual levels around the time of birth. The reason for this fall in blood pressure is that your blood vessels widen or dilate when you are pregnant. This significantly lessens the resistance to blood flow in your vascular system which in turn lowers your blood pressure. This is why in those old English dramas the young woman faints and then everyone suddenly realises she is pregnant. Believe me this is not a particularly pleasant symptom of pregnancy.

Why do all these changes occur?

Well your kids become parasites long before they start borrowing your car to go out with their friends – they are parasites from the moment you conceive. All of the changes described above occur with only one intention – and that is not purely to make their mothers suffer. These changes occur to support firstly the growth and development of the placenta and then to ensure as much blood as possible goes to your placenta in order to feed your baby and give it lots of oxygen. Babies are just like the things in the Alien movies (I suppose we should be grateful they aren’t born like the things in the Alien movies!).

And then there is the Nausea and Vomiting…

We believe the nausea and vomiting (N and V) is an effect of the pregnancy hormone HCG although it is likely the explanation is not quite so simple. We don’t really know why some women have very little nausea while others wind up hospitalised on a drip and antinausea drugs because of vomiting causing dehydration.
And whoever coined the phrase “Morning Sickness” should be shot. Most women will tell you their symptoms last all day.


If you add the N and V to the exhaustion and the need to pee every five minutes you can see that the first trimester of pregnancy is not much fun for many women.

And there is more bad news, I’m afraid:

When pregnancy was first discovered and linked to the menstrual cycle someone – almost certainly a man – said, “Hmmm pregnancy is nine lunar months so we can divide that nicely into three trimesters of three months each!” Being a man he probably marvelled at his own brilliance. A woman would have told him that the first trimester lasts up to four months and I’m afraid to say she would have been right!

OK so what does all of this have to do with hydration?

Quite a lot, actually.

The physiological changes mentioned above almost certainly mean that pregnant women should be consuming somewhere between one and two litres of fluid over and above that which they would normally drink when they are not pregnant. The problem is that with the nausea and vomiting it is very difficult to drink that much and – strangely – women get really sick of drinking water.
I might digress here to make an important point. You don’t have to measure the amount of fluid you drink when you are pregnant (or not pregnant, for that matter). Your body is smart and tells you when you are short of fluid – you become thirsty. The correct amount for you to drink is that which quenches your thirst. Full stop.

Aquamamma was invented with the specific hydration needs of pregnant women in mind.