New research published in JAMA has found that pregnant women are more susceptible to infection with the bacterium Haemophilus influenzae, which may put them at increased risk of fetal loss, preterm birth and stillbirth.
According to the research team, led by Sarah Collins of Public Health England in the UK, past studies have suggested that women may have an increased risk of invasive H. influenzae disease during pregnancy, but they note that this association was based on a small number of cases.
To investigate the link further, the investigators analyzed the outcomes of invasive H. influenzae disease over a 4-year period in women aged 15-44 years from England and Wales.
Data was gathered from doctors who cared for the women between 2009-2012. They were asked to complete a clinical questionnaire 3 months after a woman was infected.
Results of the analysis reveal that the number of women who had laboratory-confirmed invasive H. influenzae disease was low, at 0.50 per 100,000 (171 women). However, 71 of these women were pregnant at the time of infection.
The team found that pregnant women were at higher risk of infection from an unencapsulated (nontypeable) strain of the bacterium.
Of women who were infected with the unencapsulated strain during the first 24 weeks of pregnancy, 93.6% experienced fetal loss, while 6.4% experienced extremely premature birth.
Of women who had unencapsulated infection during the second half of pregnancy, 28.6% experienced premature birth and 7.1% experienced stillbirth.
H. influenzae infection 'should be identified early and treated rapidly'
The researchers point out that in addition to the serious infection, infants born prematurely were also at risk of long-term complications associated with preterm birth.
On comparing the rate of pregnancy loss in women following invasive H. influenzae disease with the UK national average, the researchers found it was 2.9 times higher.
The investigators say their findings provide evidence that H. influenzae is a very serious infection during pregnancy and add:
"Even though none of the pregnant women died in this study, the high rate of pregnancy loss makes H. influenzae an important pathogen to identify early and treat rapidly."
The investigators point out that since the study only involved follow-up of laboratory-confirmed invasive cases, their estimated rates should be considered a minimum.
In an editorial linked to the study, Dr. Morven S. Edwards, of the Bayor College of Medicine in Houston, TX, says laboratories should be aware that H. influenzae, particularly unenscapulated strains, "are potential pathogens in pregnant women and neonates."
She adds that guidelines should be designed to ensure blood samples, and other appropriate samples, are taken from pregnant women to determine how bacterial infections, such as H. influenzae, contribute to fetal loss, stillbirth and premature birth.
"Reaching these goals would go a long way toward improving child and maternal health globally," she concludes.
Medical News Today recently reported on a study suggesting that there may be a link between bacteria and premature preterm rupture of membranes (PPROM) - when the water sack around the baby breaks prematurely.