Article date: May 2010
Selective serotonin reuptake inhibitors (SSRIs) and serotonin and noradrenaline reuptake inhibitors (SNRIs) are antidepressant medicines. A review of epidemiological data has suggested that the use of SSRIs in pregnancy, particularly in the later stages, may increase the risk of persistent pulmonary hypertension in the newborn (PPHN). The observed risk was approximately five cases per 1000 pregnancies whereas the background rate in the general population is one to two cases of PPHN per 1000 pregnancies. PPHN presents as severe hypoxaemia due to pulmonary artery hypertension.
A retrospective study by Chambers and colleagues 1 reported an increased risk of PPHN in those exposed after 20 weeks’ gestation (odds ratio 6·1 [95% CI 2·2–16·8]), but no increased risk of PPHN in fetuses exposed to SSRIs before 20 weeks’ gestation.
A recent epidemiological study conducted by Kallen and Olausson2 aimed to verify the observation of an association between maternal use of SSRIs and PPHN using exposure information recorded before the pregnancy outcome was known. The study was based on the Swedish medical birth register covering 1997–2005: infants born to women who had used an SSRI during pregnancy during this period were compared with all other infants recorded in the birth register for those years (n=831 324).
After adjustment, an association between maternal SSRI use and PPHN in births after 34 weeks of gestation carried a risk ratio of 2·4 (95% CI 1·2–4·3) based on women who reported SSRI use in early pregnancy. From a subgroup who also had prescriptions for an SSRI from antenatal care later in pregnancy, the risk estimate was 3·6 (1·2–8·3).2
Although there is no evidence for the association of PPHN to SNRI treatment, this potential risk cannot be ruled out taking into account the related mechanisms of action.
Advice for healthcare professionals:
- Healthcare professionals, including midwives, should be aware of the increased risk of PPHN associated with all SSRIs and potentially with SNRIs. The observed increase in risk is about an extra 3–4 cases of PPHN per 1000 pregnancies
- In light of these new data, healthcare professionals are encouraged to enquire about the use of these medicines, particularly in women in the later stages of pregnancy
- Close observation of neonates exposed to SSRIs or SNRIs for signs of PPHN is recommended after birth
Article citation: Drug Safety Update May 2010, vol 3 issue 10: 2.