Pregnant women are at a raised risk of infection with an organism known as Haemophilus influenzae, British researchers warned today.
The bacteria can cause illnesses including respiratory infections, and may raise the risk of poor pregnancy outcomes such as premature birth and stillbirth.
Dr Sarah Collins of Public Health England, London, UK and colleagues looked at the outcomes of H influenzae disease in women of reproductive age over the course of four years. They used surveillance figures from Public Health England, which covers England and Wales. Questionnaires were sent to GPs who cared for women aged 15 to 44 who had laboratory-confirmed invasive H influenzae disease during 2009 to 2012.
This showed that the rate of the disease was low, at 0.50 per 100,000 women. But pregnant women were at higher risk of infection with unencapsulated (a category of strain) H influenzae disease risk. If infected during the first 24 weeks of pregnancy, the woman had a 94% higher risk of losing the foetus, and a 6% higher risk of extremely premature birth.
Infection during the second half of pregnancy was linked to premature birth for 29% of women, and stillbirth for 7% of women. Surviving babies were at risk of the long-term complications of prematurity. The study is published today (19 March) in the Journal of the American Medical Association.
Almost all infections were associated with miscarriage, stillbirth, or premature birth, say the authors, which indicated severity of infection in pregnant women.
They write: "Although none of the pregnant women died, 73 of the 75 pregnancies were associated with miscarriage or labour at the time of infection. In particular, all but three infections occurring during the first 24 weeks of pregnancy ended in miscarriage, whereas the remaining three resulted in extremely premature births."
Collins, S. et al. Risk of Invasive Haemophilus influenzae Infection During Pregnancy and Association With Adverse Fetal Outcomes. JAMA 19 March 2014 doi:10.1001/jama.2014.1878
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