Antidepressant use presents a risk for postpartum haemorrhage
Antidepressant use in the later stages of pregnancy is associated with a higher risk of postpartum haemorrhage (PPH), according to a recent systematic review and meta-analysis.
Women who had taken antidepressants during pregnancy had a 1.32-fold elevated risk of developing PPH compared with women who had not taken antidepressants (risk ratio [RR], 1.32, 95 percent confidence interval [CI], 1.17─1.48; p<0.001). Incidentally, this elevated risk only applied to current (RR, 1.37, 95 percent CI, 1.09─1.71; p<0.001) and recent users (within 30 days prior to delivery; RR, 1.32, 95 percent CI, 1.15─1.51; p<0.001) of antidepressants, but not past users (RR, 1.08, 95 percent CI, 0.88─1.31; p=0.463). [J Psychiatr Res 2016;83:160-167]
The risk of PPH appeared to be highest in women who had taken serotonin-norepinephrine reuptake inhibitors (SNRIs) with a 1.62-fold elevated risk (95 percent CI, 1.41─1.85), particularly women who were recent or current users (RR, 1.73, 95 percent CI, 1.50─2.00 and RR, 1.79, 95 percent CI, 1.53─2.10, respectively).
The elevated risk was still demonstrated in women who took nonserotonin reuptake inhibitors (non-SRIs; RR, 1.31, 95 percent CI, 1.10─1.56; p=0.331), serotonin reuptake inhibitors (SRIs; RR, 1.23, 95 percent CI, 1.06─1.44; p<0.001), or selective serotonin reuptake inhibitors (SSRIs; RR, 1.20, 95 percent CI, 1.04─1.38; p<0.001) but to a lesser degree.
The elevated risk also applied to both vaginal and Caesarean deliveries (RR, 1.43, 95 percent CI, 1.15─1.78 and RR, 2.02, 95 percent CI, 1.61─2.54, respectively).
To assess the risk of PPH among antidepressant users, researchers looked at eight studies published between 2008 and 2016 which included a total of 572,686 women, of whom 48,784 had PPH.
“Because platelets do not synthesize serotonin, the use of SRIs could decrease the level of serotonin in platelets, thereby impairing the efficiency of platelet-mediated haemostasis. This provides a biologically plausible mechanism for the positive association between SRI use during pregnancy and PPH,” said the study authors.
However, other mechanisms may also be involved, they said, citing the example of SNRIs that have been known to increase blood pressure in certain patients and thus, could be responsible for PPH due to the link between hypertensive disorders and PPH risk.
The authors acknowledged that imprecise measurements of blood loss and residual confounding in the observational studies are among factors that could have influenced the results of the meta-analysis, and called for more large-scaled, well-designed trials to conclusively establish the antidepressant-PPH link.