Taking antidepressants while pregnant raises the odds of gestational diabetes, a major study has found.
Researchers uncovered the link after analysing every birth in Quebec, Canada, between 1998 and 2015.
They found expectant mothers who took antidepressants were 19 per cent more likely to get gestational diabetes.
Two drugs in particular - amitriptyline and venlafaxine - had an even greater risk of mothers-to-be developing the condition.
Amitriptyline, which belongs to a class of antidepressants known as tricyclics and is branded as Elavil, put women at a 52 per cent heightened risk.
Venlafaxine, a serotonin and norepinephrine reuptake inhibitor (SNRI) sold under the brand name Efexor XL, was linked to a 27 per cent increased risk.
Women who take antidepressants face a significantly higher risk of gestational diabetes, a major study suggests. But researchers say it should not turn off severely depressed women from taking them (file image)
Researchers at the CHU Sainte-Justine medical centre in Montreal say the findings should not worry severely depressed women.
The study, published in the online journal British Medical Journal (BMJ) Open, is an observational one and can't establish a cause.
The experts, led by Professor Maelle Dandjinou, also said there was no link to gestational diabetes in women taking SSRIs - the most common antidepressants.
In the UK, fluoxetine is probably the best known SSRI and it is sold under the brand name Prozac.
The researchers speculate that antidepressants directly affect glucose metabolism, particularly as serotonin is involved in this process.
Serotonin is found in the pancreas, specifically in the beta cells that release insulin to regulate blood glucose levels.
Recent studies have shown the hormone to play a key role in controlling insulin secretion and that its absence leads to diabetes.
Gestational diabetes is a type of diabetes that affects pregnant women, usually during the second or third trimester.
Women with gestational diabetes do not have diabetes before their pregnancy. It usually goes away after the birth.
It occurs when the hormones produced during pregnancy make it difficult for your body to use insulin properly, putting you at an increased risk of insulin resistance.
Treatment focuses on managing blood sugar levels through diet, exercise and sometimes medication.