Thyrotoxicosis and Pregnancy
An overactive thyroid is very common, affecting about 1 in 200 people who are pregnant. If the thyroid is not treated this can be very important for both you and your baby. We want to work with you to make sure things go as smoothly as possible. We hope that this page will answer many of the questions that you might have – we will see you regularly in clinic and can answer any questions you have as you go along.
How should I plan for pregnancy?
Before trying to get pregnant, it is important that your thyroid is as well controlled as possible. Your doctor at the surgery and in clinic will discuss this with you. We will discuss with you particularly about any drugs you are taking to treat the thyroid. As with all women planning a pregnancy, we would advise you take 400mcg folic acid every day for 3 months before you get pregnant and through the first trimester.
Anti-Thyroid drugs in pregnancy
Most people in the UK who are treated with drugs to treat an overactive thyroid will be on a drug called carbimazole – before pregnancy we will talk to you about considering changing over to the alternative drug to treat an overactive thyroid called propylthiouracil. This is because there have been some cases reported of abnormalities in babies born to mothers who have taken carbimazole in early pregnancy.
If you are pregnant unexpectedly on carbimazole do not worry – just discuss this with your doctor and with the hospital team when you come to clinic.
How will the Thyroid be monitored in pregnancy?
To keep a close eye on the thyroid we will see you in the ante-natal clinic throughout your pregnancy.
As soon as you know you are pregnant it is important to see your doctor who will refer you to the ante-natal clinic. At that time if you have not had a thyroid blood test within the past 4 weeks please ask your doctor to arrange one as this will help us to change your treatment if needed when we first see you – if this is not possible then don’t worry as we can do this on the day. Once you have been referred to the antenatal clinic, we will see you within a couple of weeks to see how things are going.
We will continue to see you as needed in the ante-natal clinic to make sure the thyroid is okay and to change your drugs as needed – it may well be possible to come off the treatment all together in the last few weeks of pregnancy – we will discuss this with you.
If you are on a low dose of anti-thyroid drugs when you become pregnant, it is possible we will be able to stop these. If we do this, we will check the thyroid blood test every 1-2 weeks at least initially to make sure the overactive thyroid doesn’t come back.
Very occasionally people do not get on at all with the drugs to treat the thyroid – or the thyroid is very difficult to control. In this scenario we would consider surgery to remove the thyroid in pregnancy. We will discuss this with you if this looks like it might be the best option for you – it is important to remember that doing this would be very unusual and most people go through pregnancy without any problems.
Will the overactive Thyroid affect my baby?
There are a number of reasons why people have an overactive thyroid.
The commonest cause in young women is a condition called Grave’s disease.
We will discuss with you why your thyroid is overactive and will talk through with you what additional checks we recommend keeping an eye on your baby.
If you have Grave’s disease, then we will measure the levels of antibodies in the blood against the thyroid and will discuss with you what these mean – if the antibodies are raised there is a chance these will cross the placenta and make baby’s thyroid overactive – if the antibodies are raised we will recommend some additional monitoring of baby towards the end of pregnancy. This will usually involve monitoring baby’s heart rate every 2 weeks from 28 weeks and also regular growth scans. We will discuss all the results with you as we go along.
We will also recommend these additional checks if you have an overactive thyroid for any other reason and the thyroid is not perfectly controlled.
What about delivery?
There is no reason why you cannot have a normal delivery. However, we would suggest that you have your baby in hospital.
What about after delivery?
Post-delivery you should see your GP after 6 weeks and have another thyroid blood test. Your GP will then continue to see you regularly. It is possible that the thyroid will become more overactive and we will need to change your treatment – we will discuss all this with you.
There is a very small chance that your baby will have an overactive thyroid for a few weeks after they are born – we will discuss this possibility with you in the clinic and particularly what to look out for. In the unlikely event that this does occur then this can be treated with the same thyroid drugs you may been taking.
Can I breast feed if I am taking drugs for my Thyroid?
Yes. The amounts of the thyroid drugs which appear in breast milk are very small and breast feeding is safe.
I have had Grave’s disease in the past treated with Surgery or Radioactive Iodine – will I need any special monitoring?
Although you now have normal thyroid function, the antibodies which caused the Grave’s disease in the first place may still be present in your blood. These antibodies may cross over the placenta into baby and make baby’s thyroid overactive. It is therefore important that you are monitored in pregnancy. We recommend exactly the same monitoring as women who are treated with anti-thyroid drugs in pregnancy – we will check the thyroid antibodies early in pregnancy and then at 24 weeks and if these are raised will suggest some additional monitoring to keep an eye on your baby. This will include an ultrasound to look at baby’s growth every 4 weeks from 28 weeks and a listen in to baby’s heart beat every 2 weeks from 28 weeks. We will see you in clinic at 32 and 36 weeks and will discuss all this with you.
If having had surgery or radioactive iodine and you are on thyroxine replacement treatment, we will be seeing you regularly anyway to monitor this.
Ìý
Our staff at Salisbury District Hospital have long been well regarded for the quality of care and treatment they provide for our patients and for their innovation, commitment and professionalism. This has been recognised in a wide range of achievements and it is reflected in our award of ¿´Æ¬Èí¼þ Foundation Trust status. This is afforded to hospitals that provide the highest standards of care.
