Maternal Smoking Before and During Pregnancy and the Risk of Sudden Unexpected Infant Death

Tatiana M. Ander­son

OBJECTIVES: Mater­nal smok­ing dur­ing preg­nan­cy is an estab­lished risk fac­tor for sud­den unex­pect­ed infant death (SUID). Here, we aim to inves­ti­gate the effects of mater­nal prepreg­nan­cy smok­ing, reduc­tion dur­ing preg­nan­cy, and smok­ing dur­ing preg­nan­cy on SUID rates.

RESULTSSUID risk more than dou­bled (adjust­ed odds ratio [aOR] = 2.44; 95% con­fi­dence inter­val [CI] 2.31–2.57) with any mater­nal smok­ing dur­ing preg­nan­cy and increased twofold between no smok­ing and smok­ing 1 cig­a­rette dai­ly through­out preg­nan­cy. For 1 to 20 cig­a­rettes per day, the prob­a­bil­i­ty of SUID increased lin­ear­ly, with each addi­tion­al cig­a­rette smoked per day increas­ing the odds by 0.07 from 1 to 20 cig­a­rettes; beyond 20 cig­a­rettes, the rela­tion­ship plateaued. Moth­ers who quit or reduced their smok­ing decreased their odds com­pared with those who con­tin­ued smok­ing (reduced: aOR = 0.88, 95% CI 0.79–0.98; quit: aOR = 0.77, 95% CI 0.67–0.87). If we assume causal­i­ty, 22% of SUIDs in the Unit­ed States can be direct­ly attrib­uted to mater­nal smok­ing dur­ing preg­nan­cy.

CONCLUSIONS: These data sup­port the need for smok­ing ces­sa­tion before preg­nan­cy. If no women smoked in preg­nan­cy, SUID rates in the Unit­ed States could be reduced sub­stan­tial­ly.