Smoking, snuff use in pregnancy raises risk for sudden infant death syndrome
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Children of mothers who used snuff or smoked during pregnancy had higher risks for postneonatal mortality, sudden infant death syndrome and sudden unexpected infant death, according to study results published in Pediatric Research.
“The common substance in cigarette smoke and snuff is nicotine,” Anna Gunnerbeck, PhD, pediatrician at Astrid Lindgren Children's Hospital and researcher in the department of medical epidemiology and biostatistics at Karolinska Institutet, told Healio. “Our findings suggest that nicotine contributes to an elevated risk of sudden infant death syndrome. The implication of our findings is that all forms of nicotine should be avoided in pregnancy.”
In a population-based register study, Gunnerbeck and colleagues analyzed 2,061,514 infants born in Sweden between 1999 and 2019 to determine if Swedish snuff, or noncombustible nicotine, and smoking during early pregnancy increased risk for postneonatal mortality, sudden infant death syndrome (SIDS) or sudden unexpected infant death (SUID) using multiple logistic regression models. Researchers also evaluated whether quitting smoking before the first antenatal visit had an impact on these risks.
Researchers used prospectively collected data from the Swedish Medical Birth Registry on self-reported tobacco use in early pregnancy, including: nonuse (n = 1,893,643), snuff use (n = 22,799), moderate smoking (< 10 cigarettes/day; n = 108,987) and heavy smoking (≥ 10 cigarettes/day; n = 36,085).
Researchers observed a postneonatal mortality rate of 0.8 per 1,000 live-born infants (n = 1,583), with nearly 32% of these infants born preterm and 28% born small for gestational age (SGA).
Researchers observed a greater risk for postneonatal mortality among infants whose mothers used snuff in pregnancy (adjusted OR = 1.71; 95% CI, 1.16-2.53) or were moderate smokers (aOR = 1.89; 95% CI, 1.6-2.24) or heavy smokers (aOR = 2.72; 95% CI, 2.17-3.4) compared with nonusers.
Within the cohort, 381 infants died of SIDS. The risk for this outcome increased with snuff use (aOR = 3.7; 95% CI, 2.06-6.65), moderate smoking (aOR = 4.31; 95% CI, 3.26-5.7) and heavy smoking (aOR = 7.03; 95% CI, 5.04-9.79).
Also, 611 infants died of SUID, 60% of which were due to SIDS. Risk for SUID increased with snuff use (aOR = 2.9; 95% CI, 1.75-4.8), moderate smoking (aOR = 3.2; 95% CI, 2.53-4.05) and heavy smoking (aOR = 5.44; 95% CI, 4.1-7.22).
When adjusting for confounders, researchers found reduced relationships in all the analyses. However, in an analysis of only term and non-SGA infants (n = 1,824,357), researchers observed mortality outcomes related to smoking and snuff use comparable to the main analysis.
Before their first antenatal booking, more than 50% of those who smoked and nearly 70% of those who used snuff quit.
Although infants of mothers who quit using snuff still had a greater risk for SIDS compared with nonusers, they had a lower adjusted odds ratio than persistent users (aOR = 2.13; 95% CI, 1.04-4.34). Infants of mothers who quit smoking (aOR = 1.35; 95% CI, 0.89-2.05) had a lower adjusted odds ratio for SIDS than those of mothers who continued smoking, but it remained higher than that of nonusers.
Infants of mothers who either stopped smoking (aOR = 1.29; 95% CI, 0.95-1.74) or using snuff (aOR = 1.37; 95% CI, 0.73-2.58) also showed lower SUID risk when comparing their adjusted odds ratios with those of persistent users.
Researchers found no significantly elevated risks for postneonatal mortality among those who stopped smoking or snuff use.
“Increasing knowledge about the detrimental effects of smoking has led to a growing market of various non-combustible nicotine products normally regarded as being less harmful than cigarettes,” Gunnerbeck told Healio. “The evolving market of new nicotine products places high demands on society and health care professionals regarding preventive strategies.”
Epidemiological register studies like this one show associations, but not causal effects, Gunnerbeck added.
“Studies of other noncombustible nicotine products in pregnancy, such as the use of electronic nicotine devices, would add to the current knowledge,” she said, adding that young women have been increasing using these products.
“Increasing knowledge of the effects of these products in pregnancy is of the utmost importance,” she said.
For more information:
Anna Gunnerbeck, PhD, can be reached at anna.gunnerbeck@ki.se.
Reference:
- Nicotine exposure during pregnancy may increase risk of sudden infant death. https://news.ki.se/nicotine-exposure-during-pregnancy-may-increase-risk-of-sudden-infant-death. Published Feb. 8, 2023. Accessed Feb. 10, 2023.