Physicians should watch for signs of depression in their pregnant patients with asthma so treatment and coping strategies can start early, the authors write in The Journal of Allergy and Clinical Immunology: In Practice.
“We knew asthma in general (outside of pregnancy) is associated with an increased risk of depression, so we suspected that asthma during pregnancy could increase the risk of postpartum depression,” said lead author Lucie Blais, a researcher at the Universite de Montreal.
“Women with asthma should be aware of the increased risk of postpartum depression and discuss quickly with their physician if they feel depressed or elaborate a strategy to minimise the risk before delivery,” Blais told Reuters Health in an e-mail.
To assess the risk, Blais and her colleagues compared the health histories of more than 35,000 pregnant women with asthma and almost 200,000 women without asthma who delivered babies in Quebec between 1998 and 2009.
In the year after delivery, rates of postpartum depression were roughly double among women with asthma.
At one month postpartum, 0.8% of women with asthma were depressed, compared to 0.4% of women without asthma. At three months, about 2% of women with asthma had a depression diagnosis compared to 1% of women without asthma. And at one year, about 6% of women with asthma had postpartum depression compared to about 3% of women without asthma.
The researchers also considered other health conditions and demographic information and found that women with asthma were more likely to be under age 25, to live in urban areas and to have chronic diseases or pregnancy-related disorders.
In addition, the rates of preterm birth, caesarean delivery, low birth weight, poor fetal growth, or a congenital malformation at delivery were greater among women with asthma.
After taking these factors into account, including history of depression, the authors calculated that women with asthma were still 58% more likely than those without asthma to experience postpartum depression.
It’s not clear why having asthma during pregnancy would increase the risk of postpartum depression, the authors note. However, it might be due to increased feelings of anxiety or stress among women with asthma. Inflammation might also play a role.
“Asthma and depression might share inflammatory processes and/or the difficulty to deal with a chronic disease while becoming a mother with several associated tasks and responsibilities,” Blais said.
About one in every seven new mothers experiences postpartum depression, according to the American Psychological Association, and for about half, it may be their first episode of depression.