There are many circumstances that affect whether a woman decides to end a pregnancy which we simply can't change.
We can't conjure up the financial security she wants before she brings a child into the world, however important the campaign for secure maternity benefits and high quality, affordable childcare.
We can't transform the man she's accidentally conceived with into the man she wants to start a family with. We can't eliminate the needs of her existing children whom she feels must come first.
But every now and then, there are things we really can do to make a difference.
Everyday, women find themselves in the tragic situation of being told their pregnancy is affected by a neural tube defect (NTD) such as spina bifida or anencephaly. Spina bifida causes serious lifelong disability while anencephaly, where the baby's skull and brain do not form properly, is always fatal. This country has one of the highest rates of these conditions in the European Union, resulting in an estimated 1,000 cases per year, not including those that end in miscarriage.
The most effective way to reduce NTDs is for women to take a supplement of folic acid in the months before they start trying for a baby, as the neural tube develops in the very early stages of pregnancy - before a woman often knows she's expecting. But as we in our service know only too well, pregnancies happen when women are often least expecting them. Two thirds of the women we see with an unplanned pregnancy report using contraception when they conceived.
Many unplanned pregnancies end in abortion, but many others are greeted as welcome surprises. It's estimated that between one third and a half of babies are the product of these happy accidents.
But happy endings are not guaranteed.
We believe it's simply unrealistic to expect women who are not planning a pregnancy to be taking folic acid supplements on the basis that they might conceive. Fortifying our flour with folic acid would mean that this vital nutrient entered everyday foods widely consumed by women of childbearing age, whether they were trying for a baby or not, and prevent hundreds of cases of spina bifida and anencephaly a year.
It could spare a couple a day from the heartbreaking decision to end what was a much wanted pregnancy. These cases are among the saddest we see in our clinics.
It is now six years since the Scientific Advisory Committee on Nutrition (SACN) first recommended flour be fortified - and the UK's chief medical officers considered and approved that recommendation. The UK has been adding calcium, thiamin, niacin and iron to wheat flour for more than 50 years so both the principles and the mechanics of fortification are already in place.
The move is supported by disability organisations and those involved in women's pregnancy care like bpas. The decision now lies in the hands of UK health ministers.
They should follow the example of the US, Canada and Australia, which have all introduced fortification. There is now no evidence of any adverse impact on the rest of the population, but plenty to show this protects women and their babies.
It was scientists from the UK's Medical Research Council who proved in the early 1990s that folic acid could prevent these defects. More than two decades have passed and it's now high time that UK women and their babies were able to reap the full benefits of their work.