What You Need to Know About Kidney Stones in Pregnancy

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It turns out I spoke too soon and ended up with another hospital trip over the weekend.
But, as promised, I’m going to put the past month and a half’s worth of hospital visits, doctor’s notes and NHS time to good use.

When I was initially diagnosed with kidney trouble: renal colic and potential kidney stones on 1st June, I did what many of us with internet access do and started to research online the condition, medication and potential impact on my pregnancy. Whilst NHS Choices (UK) and the National Kidney Foundation (USA) provide detailed explanations of what kidney stones are, how they form, treatment options and comprehensive lists of symptoms, they have little relating specifically to pregnancy.

The reason it is so hard to find out about kidney stones in pregnancy is because they don’t occur frequently enough to be classified as part of a ‘normal‘ pregnancy (which, by the way, does not exist). Most online information revolves around prevention, which is great, as the famous Benjamin Franklin quote says: ‘an ounce of prevention is worth a pound of cure’. But we pregnant women already pile huge amounts of blame and pressure on ourselves regarding what we are doing and experiencing throughout gestation and reading that drinking more water might have prevented this current agony does not help. Besides, in pregnancy, kidney stones are about more than mere hydration.

My online research wasn’t giving me much so I wanted to convert the oral information given to me at the numerous appointments with obstetricians, general practitioners and urologists into a post for the benefit of others.

Why Does Pregnancy Make You More Susceptible to Kidney Stones?

Hydration is of course important at all times and during pregnancy a woman’s body does require more fluid for the changes and creations that are occurring. These changes result in the body working harder, including the kidneys.

1. Increased blood volume during pregnancy means increased filtration for your kidneys as they work to remove waste and return nutrients. With increased water consumption the kidneys ideally have enough fluid to filter effectively and prevent the crystallisation of minerals within the organ which can develop into kidney stones. Yet increased blood volume equates to more work and there are more minerals to filter.

2. There are several different types of kidney stone, the most common being composed of crystallised calcium. In addition to increased blood volume during pregnancy, there is also more calcium in your blood because of the developing fetus. Not only is your body absorbing more calcium during pregnancy, but your kidneys are also extracting more, potentially leading to an increased build up of this mineral either as crystals or, eventually, as stones.

3. In addition to your kidneys working harder for you with increased blood volume and calcium extraction, they are also working for your baby. Although the major organs are formed early on in gestation, the fetus still has no kidney function of its own until 10 weeks. At this time your baby begins to drink from the amniotic fluid surrounding it, produce urine and replenish the amniotic sac.

4. However, despite babies having their own kidneys from 10 weeks onwards, you body is still doing a lot of the work until the very last stages of pregnancy. Although the fetus is producing urine, there is still plenty of waste, excess water and other substances transferred between mum and baby via the umbilical cord. It is mum’s kidneys that are then filtering and extracting these extra materials prolonging their increased workload.

5. As with many medical conditions kidney stones have a tendency to reoccur. If you have had kidney stones in the past you have an increased chance of developing them again, especially during the extra strain of pregnancy.

Should You Worry?

I experienced a brief lull and calm after receiving a diagnosis. However, it didn’t last long as although I now had some comfort from what was causing the extreme pain I was experiencing, my thoughts turned immediately to what this might mean for my unborn child.

This was what fuelled my initial online search for information about kidney stones. Typing kidney stones and pregnancy into a search engine can result in some pretty concerning, yet entirely unrelated, findings. Predominately, the results generated will be to do with kidney infections, kidney failure or urinary tract infections. In comparison, kidney stones are not something to fret about. They can be incredibly painful, but it is mainly an issue that affects mum as opposed to baby. The main problems from kidney stones result from pregnancy rather than the other way around.

1. As I have detailed in another post dedicated to medication, there are very few pain management options available during pregnancy. It is usually this, rather than the condition, that results in the increased rates of hospitalisation for pregnant women with kidney stones, not the stones themselves.

2. Usually, kidney stones are left largely to their own devices. This should immediately reduce the rate of alarm because if there were risks to the fetus you can guarantee that there would be very swift action taken (as there would be in the case of infection). Whilst it is far from a pleasant experience, most stones are small enough to pass on their own.

Particularly large stones can cause blockages and then interventions will be investigated. Treatment of kidney stones is complicated by pregnancy as the most accurate method of detecting them is x-ray, which of course will not be used on an expectant mother. Some doctors believe that the risks are negligible but this is a conversation that you would need to have with the consultant or urologist. Ultrasound is the alternative and is still very accurate for detecting large stones, or their presence if the kidney is swollen or puffy.

In the case of blockage or infection (as with urinary tract infections which can be delightfully frequent in pregnancy) there can be a risk to your baby if your temperature rises or a fever develops for a prolonged period. It is always advised that you contact your health professional in the case of developing a temperature, whatever the cause.

Treatment

In these cases treatment appears to be the same for both pregnant and non-pregnant patients. Ultrasound waves may be used to break down the stone (given the much more alarming treatment term of extracorporeal shock wave lithotripsy – eek!) or surgery. Today, it is rare for open surgery to be performed with a ureteroscopy being the more likely.

Antibiotics will be used to treat infection, opening up an entirely different set of decisions for pregnant women and their healthcare providers. As with pain management the options are limited and it may be decided to administer them in hospital rather than with a take home prescription.

As usual, this post carries the disclaimer that I have no medical training and that any symptoms that are causing concern should be discussed with a health professional and not self-diagnosed on the internet. This post is intended to compile information and highlight options, not to advise.

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