Sudden infant death syndrome (
SIDS),
neonatal deaths, and deaths from
infection are higher among Indigenous Australians. This study aimed to determine the effects of inflammatory responses and exposure to cigarette
smoke, two important factors associated with
sudden death in infancy, on
preterm birth, and
birth weight in a cohort of Indigenous mothers. Indigenous Australian women (n = 131) were recruited as part of a longitudinal study while attending
antenatal care clinics during pregnancy; blood samples were collected up to three times in pregnancy. Serum
cotinine, indicating exposure to cigarette
smoke, was detected in 50.4% of mothers. Compared with non-Indigenous women, the cohort had 10 times the prevalence of
antibodies to Helicobacter pylori (33 vs. 3%). Levels of
immunoglobulin G,
antibodies to H. pylori, and
C-reactive protein (CRP) were all inversely correlated with gestational age (P < 0.05). CRP levels were positively associated with maternal body mass index (BMI; ρ = 0.449, P = 0.001). The effects of cigarette
smoke (
cotinine) and
inflammation (CRP) were assessed in relation to risk factors for
SIDS: gestational age at delivery and
birth weight. Serum
cotinine levels were negatively associated with
birth weight (ρ = -0.37, P < 0.001), this correlation held true for both male (ρ = -0.39, P = 0.002) and female (ρ = -0.30, P = 0.017) infants.
Cotinine was negatively associated with gestational age at delivery (ρ = -0.199, P = 0.023). When assessed by fetal sex, this was significant only for males (ρ = -0.327, P = 0.011). CRP was negatively associated with gestational age at delivery for female infants (ρ = -0.46, P < 0.001). In contrast, maternal BMI was significantly correlated with
birth weight. These data highlight the importance of putting programs in place to reduce cigarette
smoke exposure in pregnancy and to treat women with
chronic infections such as H. pylori to improve pregnancy outcomes and decrease risk factors for
sudden death in infancy.