One of the most fundamental points about pregnancy in mammals is the growth involved. In everything from mice to the blue whale, it is a process that starts with two cells and finishes with a trillion or more. A fact that surprised me is that in humans, the support system required is far bigger than the baby itself. Just the placenta is the same size as the foetus or bigger, for most of the pregnancy. The things behind the placenta also grow. The mother’s blood, liver and heart all expand considerably. The uterus expands by 500 times during pregnancy. There is also a rationale for storing energy to provide the chemical materials for breastfeeding, the most obvious being fats.

It is no surprise then that women gain weight during the pregnancy, and in a way that correlates with the child’s growth and thus age. Despite this, I was concerned to hear of women who weighed 50 Kg before pregnancy putting on 22 Kg during it. It even made me wonder how good an example they were–was that 22 Kg down to the base rate, so to speak, or was it partly down to a bit extra that arose from eating being out of step with the need?

There is a reasonable point here, a pregnant woman’s energy expenditure and income shift rather a lot, and perhaps even her appetite does, during pregnancy. There is also an element of transition, it changes throughout the procedure, and then again afterwards. I think this makes it basically impossible to be prescriptive such that in any given week or month, a certain amount should be eaten. There is some quite clear advice that certain nutrients should not be taken in top high a quantity, e.g. Vitamine A during the first three months.

This growth means that there is a lot more weight to carry around–as much as 20 Kg perhaps. As someone who lost 25 Kg in six months, I have some clue about the right order of magnitude for this kind of change, but my experience is in the wrong direction for pregnancy, and came with increased fitness and mobility. During pregnancy fitness goes down, because movement and the ability to take large breaths is reduced. If we add the effects of progesterone, and thus the digestive discomfort and spinal pain, the reasons for pregnant women needing support stack up really rather strongly. So, the support a woman needs during pregnancy should probably be as fundamental as the growth of the bump itself. And should very definitely not include references to landed baleens.