Subclinical hypothyroidism as a risk factor for placental abruption

Subclinical hypothyroidism as a risk factor for placental abruption

One for the midwives!

One of the very first posts on the site when it first started was about the heightened risk of breech positioning in hypothyroidism. The issues keep being reported, keep being experienced, and very sadly, keep being ignored.

Aust N Z J Obstet Gynaecol. 2013 Oct 1. doi: 10.1111/ajo.12131. [Epub ahead of print]

Subclinical hypothyroidism as a risk factor for placental abruption: Evidence from a low-risk primigravid population.

Breathnach FM, Donnelly J, Cooley SM, Geary M, Malone FD.


Department of Obstetrics and Gynaecology, Royal College of Surgeons in Ireland, Dublin, Ireland.



Subclinical thyroid hypofunction in pregnancy has been shown to have an association with neurodevelopmental delay in the offspring. It is unclear whether obstetric factors may account for this observation.


To establish the prevalence of subclinical hypothyroidism (SCH) in a low-risk primigravid population and to explore its association with obstetric sequelae.


Nine hundred and fifty-three primigravid women had thyroid hormone indices analysed in the early second trimester. Delivery and neonatal outcomes were available for 904 women who met the criteria for inclusion in the study. Women with subclinical hypothyroidism (thyroid-stimulating hormone (TSH) values at or above the 98th percentile with a normal free thyroxine (fT4)) or isolated maternal hypothyroxinaemia (fT4 level at or below the second percentile with a normal-range TSH) were compared with biochemically euthyroid controls. Chi-squared test and analysis of variance were used for statistical analysis.


The prevalence of SCH or isolated maternal hypothyroxinaemia was 4%. Positivity for antithyroid peroxidase (TPO) or antithyroglobulin (ATG) antibodies correlated with SCH status (P = 0.02). Placental abruption was observed more commonly in the setting of either SCH or isolated maternal hypothyroxinaemia when compared with euthyroid controls (P = 0.02 and 0.04, respectively).


Subclinical hypothyroidism and isolated maternal hypothyroxinaemia are associated with placental abruption. The observation of these effects in this healthy low-risk population lends weight to the case for antenatal screening for diminished thyroid reserve.

© 2013 The Royal Australian and New Zealand College of Obstetricians and Gynaecologists.


placental abruption, subclinical hypothyroidism, thyroid autoimmunity

PMID: 24111733 [PubMed - as supplied by publisher]


1 Reply

  • Very interesting!

    I had marginal placental abruption with both children - luckily not full abruption! No one made the link to my thyroid (including me). In both cases my T4 had dropped to the bottom of the range and in both cases I was told by my GP that it was too risky to increase my dose of thyroxine. Luckily, with my daughter, because I had had two miscarriages, I was referred to a foetal medicine specialist as soon as I found out I was pregnant the 4th time and when he saw that my T4 was low in range at around 24 weeks, he said it was essential my thyroxine was increased straight away! Unfortunately I still had a marginal abruption and a necessary short stay in hospital with no salt! Grrr! My blood pressure went through the floor and my pulse was so slow and irregular that they insisted on a cardiology consult after they found that I wasn't bleeding out. And there's me telling them, "It's because there's absolutely no bloody salt whatsoever in the food and no option to add it! What do you think is going to happen!" (I was very blunt when I was pregnant). Other half brought me in crisps and other salty snacks and all returned to normal :D

    I think all pregnant women should be referred to someone that has knowledge of thyroid if they have thyroid disease of any kind. There is too much risk involved if the correct doses aren't prescribed.

    Thanks for posting another interesting paper!

    Carolyn x

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