Diuretics
What are they?
Diuretics (sometimes called ‘water tablets’) increase urine production and help to get rid of excess fluid. They are used in the treatment of heart failure, high blood pressure and some kidney conditions.
Diuretics commonly used in the UK include amiloride, chlorothiazide, hydrochlorothiazide, furosemide and spironolactone.
Benefits
What are the benefits of using a diuretic in pregnancy?
Diuretics can be used in pregnancy but are rarely needed. When they are needed, it is to prevent serious complications from the build-up of excess fluid.
Risks
What are the risks of using a diuretic in pregnancy?
There is not much information on diuretics in pregnancy because hardly any pregnant women need to take them. However, there are a few issues that need to be considered:
Diuretics may reduce blood flow to the placenta. However, many of the medical conditions that you need diuretics for will also do this. Your baby will be monitored with extra growth scans.
Use of spironolactone specifically can potentially reduce testosterone levels in the baby. There are concerns that use in pregnancy could affect genital development in male babies. This has been shown in animal studies. There is a single human case report of a male baby with malformed genitals following spironolactone exposure, but also several case reports of male babies with normal genitals.
Use of a diuretic in pregnancy will only be recommended if the benefits of treating a potentially serious condition outweigh the possible risks.
Alternatives
Are there any alternatives to taking a diuretic in pregnancy?
Possibly. Women taking a diuretic to treat high blood pressure will usually be offered a different medicine that is known to be safe during pregnancy.
However, pregnant women with heart failure may be advised to continue taking a diuretic, as this can get worse during pregnancy and other drugs are unlikely to be as effective.
Swapping to a diuretic in pregnancy may be advised for women who are taking drugs called ACE-inhibitors and angiotensin receptor blockers, because these are dangerous for the baby if used in later pregnancy.
Women with conditions that affect the kidneys may also be advised to continue taking a diuretic to remain well.
If you are taking a diuretic and planning a pregnancy, speak to your doctor or specialist to make sure that this is right for you. Please do not make any changes to your medication unless your doctor has recommended this.
No treatment
What if I prefer not to take medicines in pregnancy?
It is important to take any medicines prescribed for high blood pressure, heart problems, or conditions affecting kidney function, as these can be serious for both mother and baby. A doctor will only prescribe medicines when necessary and will be happy to discuss any concerns.
Will I or my baby need extra monitoring?
As part of routine antenatal care, most women will be offered a detailed scan at around 20 weeks of pregnancy to check the baby’s development.
Women with high blood pressure, heart problems, or conditions affecting kidney function will be more closely monitored with additional growth scans during pregnancy to make sure that they remain well throughout and that their baby is growing as expected.
Are there any risks to my baby if the father has taken a diuretic?
We would not expect any increased risk to your baby if the father takes a diuretic.
Who can I talk to if I have questions?
If you have any questions regarding the information in this leaflet please discuss them with your health care provider. They can access more detailed medical and scientific information from www.uktis.org.