A recent study looks at the risk for gestational diabetes in women taking antidepressants during pregnancy.  In this study from Quebec, women with gestational diabetes mellitus (GDM) diagnosed after the 20th week of pregnancy were identified.  A group of controls, matched for gestational age at the time of GDM diagnosis and the year of pregnancy, was chosen. Antidepressant (AD) exposure was defined as filling at least one AD prescription between the beginning of pregnancy (first day of the last menstrual period) and the date GDM was identified.  Women with cystic fibrosis and those who were overweight (body mass index (BMI) >25?kg/m2) or obese (BMI >30?kg/m2) were excluded because these women have a higher risk of developing GDM.

Comparing 20,905 women with GDM to 209,050 matched controls, the researchers observed that 9741 (4.2%) of the women with GDM were exposed to antidepressants. After adjusting for potential confounders, antidepressant use was associated with a very small  increase in risk of GDM (aOR 1.19, 95%?CI 1.08 to 1.30). The risk was highest with venlafaxine (aOR 1.27, 95%?CI 1.09 to 1.49) and amitriptyline (aOR 1.52, 95%?CI 1.25 to 1.84. 

If you look at the data from individual antidepressants (which was not mentioned in the abstract), there was no increased risk of gestational diabetes associated with the SSRIs citalopram, sertraline, fluoxetine, paroxetine, and fluvoxamine.  

While this study has received considerable media attention, there are some important things to keep in mind: 

Point 1: The increase in risk is statistically significant but very small.  

Point 2:  The antidepressants most commonly used during pregnancy, the SSRIs (citalopram, sertraline, paroxetine, fluvoxamine, and fluoxetine), did not affect risk for gestational diabetes.  Risk was only associated with venlafaxine, which is used less commonly, and amitriptyline, which is used very rarely during pregnancy.  

Point 3: While the researchers attempted to control for potential confounders, they did not control for some of the most important risk factors for GDM, including weight gain during pregnancy and BMI.  We know that women with psychiatric disorders have, on average, higher BMIs than women in the general population.  Higher BMI may be related to psychiatric illness itself or to lifestyle factors associated with psychiatric illness, and we have seen that women taking certain psychotropic medications enter into pregnancy with a higher BMI which may increase their risk for gestational diabetes.  Therefore, this finding may show an association between antidepressant use and GDM, but other factors more common among women taking antidepressants may explain this association.  

The Bottom Line

Should we do anything different with regard to the use of antidepressants during pregnancy? No.  Most women use SSRIs during pregnancy, so this finding does not apply to them. But even if they were taking amitriptyline or venlafaxine (which were associated with a small increase in risk), I would not automatically discontinue their medication.  Given that the increase in risk of GDM is very small, I would weigh this risk against the risks associated with untreated illness in the mother, as well as the risk of relapse in the case of switching to another medication.  

Ruta Nonacs, MD PhD

Dandjinou M, Sheehy O, Bérard A.Antidepressant use during pregnancy and the risk of gestational diabetes mellitus: a nested case-control study.  BMJ Open. 2019 Oct 1.   Free Article

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