Table 3

Associations for maternal exposure to cough medications containing DM alone, GG alone and DM +GG during early pregnancy with NTDs, NBDPS, 1997–2011

Study groupsDM alone*GG alone†DM +GGExposure not classified
No. of non-exposed (referent)No. (%) of exposed‡cOR
(95% CI)
aOR§
(95% CI)
No. (%) of exposed‡cOR
(95% CI)
aOR§
(95% CI)
No. (%) of exposed‡cOR
(95% CI)
aOR§
(95% CI)
No.
Controls10 201128 (1.2)NANA61 (0.6)NANA19 (0.2)NANA915
NTDs¶159228 (1.7)1.4 (0.9 to 2.1)1.1 (0.7 to 1.7)17 (1.1)1.8 (1.0 to 3.1)1.8 (1.0 to 3.3)7 (0.4)2.4 (1.0 to 5.6)1.8 (0.6 to 4.8)115
Anencephaly4898 (1.6)1.3 (0.6 to 2.7)0.9 (0.3 to 2.2)3 (0.6)NCNC2 (0.4)NCNC24
Spina bifida97017 (1.7)1.4 (0.8 to 2.3)1.1 (0.6 to 1.9)12 (1.2)2.1 (1.1 to 3.9)2.2 (1.1 to 4.3)4 (0.4)NCNC80
  • *DM alone refers to maternal exposure to DM without GG.

  • †GG alone refers to maternal exposure to GG without DM.

  • ‡Exposure during the 1 month before pregnancy through the first month of pregnancy.

  • §Adjusted for child sex, first-degree family history of NTDs and study site; maternal race/ethnicity, age and educational level at delivery, prepregnancy body mass index, and hypertension diagnosed before or during pregnancy; and maternal cigarette smoking, alcohol consumption, fever and use of a supplement containing folic acid during the 1 month before pregnancy through the first month of pregnancy.

  • ¶The numbers of mothers of encephalocele case children who were exposed to DM alone (3), DM +GG (1) and GG alone (2) were insufficient to estimate associations. There were 133 non-exposed mothers of encephalocele case children and 11 mothers of encephalocele case children whose exposure was not classified.

  • aOR, adjusted OR; cOR, crude OR; DM, dextromethorphan; GG, guaifenesin (glyceryl guaiacolate); NA, not applicable; NBDPS, National Birth Defects Prevention Study; NC, not calculated; NTDs, neural tube defects.