Two studies have found women with pre-eclampsia face increased hypothyroidism risk during and after pregnancy, and that this risk can last for years.
A US study compared TSH levels in 141 women with pre-eclampsia with a control group.
TSH levels were on average 2.42 times higher in the women with pre-eclampsia when measured just before delivery.
The second study looked for associations between pre-eclampsia and TSH in 7,121 Norwegian women who had given birth in the last 20 years.
It showed that women who had pre-eclampsia in their first pregnancy were 70 per cent more likely to have raised TSH levels. The risk was higher in women who had pre-eclampsia in two consecutive pregnancies.
Dr Ananth Karumanchi, associate professor at the department of obstetrics and gynecology at Harvard Medical School and a study researcher, said: 'When GPs follow up pre-eclampsia patients after pregnancy, an easy way to monitor for this would be to measure blood levels of TSH once a year.'
The absolute risk for thyroid dysfunction in patients with pre-eclampsia is small, he added. Just 10 per cent are likely to develop the complication over a 10to 15-year follow-up.
Staffordshire GP Dr Kevan Thorley, who has an interest in pre-eclampsia, added: 'We need to be aware of the findings, but I do not think the evidence suggests altering practice.'