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The Importance of Your Thyroid During Pregnancy & Other Miscarriage Risks

Maintaining optimum health during your pregnancy is a pretty obvious statement. Along with eating right, staying hydrated and exercising throughout pregnancy there are other factors that we can both control and can't control that can affect the health of our pregnancy and the risk of miscarriage.

Thyroid Health

A foetus only starts making its own thyroid hormone from 10 to13 weeks into gestation. This means that throughout the first trimester the mother has to produce 30% more thyroid hormone to provide enough for herself and her baby.

However, if you have sub-optimal thyroid levels this can have a negative effect on a pregnancy. Thyroid Stimulating Hormone (TSH) levels, ideally between 1 - 2.5mU/L, is vital for a healthy pregnancy, but also essential for optimal function of the mother before conceiving. If you do have sub-optimal levels, recommend stop trying until you return to ideal levels. Also important to monitor thyroid levels throughout your pregnancy if you have had any issues.

In recurrent miscarriages we would recommend investigating to see if there are elevated thyroid antibodies, which can increase the risk of miscarriage. wise to double check thyroid antibodies as sometimes levels can be elevated, regardless of TSH. This can increase risk for miscarriage

Defects in the Luteal phase of menstrual cycle

The menstrual cycle has two phases:

  1. Follicular: the start of period to ovulation

  2. Luteal: after ovulation, ideally lasting for 10+ days

Within the Luteal phase, progesterone is the dominant hormone and it is essential for embryo implantation. Progesterone production from the mother supports early pregnancy until the placenta can take over making its own - around the 8 week mark.

However, testing for progesterone testing is very difficult due to:

  • Fluctuating levels throughout a woman's cycle

  • Varies from cycle to cycle

  • The test needs to be performed 7 days after ovulation, which is hard to know

  • Progesterone may peak and quickly crash

Treatment options if low progesterone is identified can be prescribed by doctors, and can include synthetic progesterone in the form of vaginal creams or oral supplementation.

Vaginal infections

Not always routinely tested unless symptomatic, so it’s best to get a sexual health check up to rule this out. On the NHS, HIV, Hep B and syphilis are tested for, but there are a wide range of other infections that can cause fertility issues.

An imbalanced vaginal microbiome can be caused by elevated levels of inflammation, which can increase the risk of miscarriage. A reduction in lactobacillus can increase inflammation.

Thankfully, testing is very easy and treatment often includes antibiotics and holistic care with probiotics to maintain a healthy vaginal microbiome.


The developing foetus is particularly susceptible to environmental pollutants such as carbon monoxide and cooking smoke. Obviously, today's modern world leaves us open to exposure every day.

So what can you do??

  • Maintain a healthy weight

  • Check for nutritional deficiencies, alongside taking a good pregnancy multivitamin

  • Complete a full thyroid panel

  • Reduce toxin exposure and DNA damaging molecules. This includes alcohol, caffeine, drugs, excessive exercise, pollution, plastics, EMF (you can read more about toxins in an earlier blog post here)

  • Avoid BPA plastics. These are linked to PCOS, infertility, endometriosis and thyroid conditions

  • Support detoxification - this is something we can help with at The Natural Balance.

  • Reduce levels of inflammation

  • Increase antioxidant intake, particularly vitamins A, C, E, selenium and zinc

  • A good sleep routine, 8-9 hours each night

  • Stress management techniques that work for you such as yoga, cooking, meditation, jogging

  • Oral hygiene. Often forgotten about, but good oral health reduces inflammation

As with any medical concerns, if you’re concerned, worried or your symptoms are not dissipating contact or visit your GP or hospital immediately.

Support after a miscarriage is available

1 in 3 women who have suffered a pregnancy loss suffer post traumatic stress disorder. If you, a loved one, a friend or family member has suffered a miscarriage there are some great resources and charities that provide emotional support and help with grief including Petals, The Miscarriage Association and Tommy’s.

If you would like to reduce your risk of miscarriage, planning for a baby, or want to find out more about how nutritional therapy can support you conceiving, why not book in a free discovery call with Gail today.

There’s no commitment, and all calls are a private and safe space to discuss your concerns.


Gail Madalena

Registered Nutritional Therapist


Gail Madalena is a registered nutritional therapist specialising in fertility, pregnancy and women’s health. Her expertise lies in hormonal imbalances, such as irregular cycles, debilitating PMS, PCOS, endometriosis, thyroid issues and sub-optimal fertility. Her goal is to reduce hormonal side effects and symptoms by addressing the root cause of the issue. Gail helps couples optimise your nutrition and lifestyle choices, supporting you on your journey to achieving a healthy pregnancy.

I am not attempting to prevent, treat or cure any physical, mental or emotional issues. Do not disregard medical advice or delay seeking medical advice because of information you have read on this website. Do not start or stop taking any medications without speaking to your primary health care provider.


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