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Table 1 Description of studies

From: Potential effects of using non-combustible tobacco and nicotine products during pregnancy: a systematic review

Citation Sample size Loc1 Pop2 Design3 Data4 Condition 5 Outcome measure6 Adjusted for7
Randomized controlled studies
[20,21,22,23,24] 1010 Eng White D_Bl, Pl SR, CO Patch, placebo BW, GA, PT, SB, NICU Ad, ApgS, MF, CD Recruitment centre
[25] 194 USA Hispanic, White D_Bl, Pl SR, CO, CR, MR Gum, placebo BW, GA, ApgS, PT, Normal distribution only
[26] 181 USA White NB SR, CR CBT, CBT+NRT BW, GA Pre-term birth
[27] 23 USA White Cr US, BP, Pulse Patch, smoking Systolic, diastolic BP, middle cerebral, umbilical or uterine arteries, fetal heart rate N/A
Cross-sectional population-based studies
[37] 379,214 NC    MR, SR (MWR) NSNNU, smoking, snus, Preeclampsia Maternal age at delivery, early pregnancy, BMI, parity, and YrsEd. Excluded dual users and multiple births
[38] 1,270,161 Sw    MR, SR (MWR) NSNNU, smoking, Snus, dual-use PT Parity, PPBMI, family situation Maternal age, maternal Country of birth, YrsEd. Excluded multiple births
[39] 609,551 NC    MR, SR NSNNU, smoking, snus SGA, Nap SGA: maternal age, height, parity, education. In addition, for apnea: infant gender, GA, SGA, delivery method
[28] 72,761 Dk    MR, TSR NSNNU, smoking, combined-NRT BW Infant sex, parity, fertility problems, maternal age, SES, MS, PPBMI, maternal weight loss during pregnancy, occupational physical strain, physical exercise, coffee, alcohol, nausea, vomiting, vaginal bleeding, eating disorder, hypertension, PSS, maternal height.
Excluded multiple births, pre-28 weeks birth,
[40] 610,879 Sw    MR, SR (MWR) NSNNU, smoking, snus SB Maternal age, PPBMI, parity, YrsEd, chronic hypertension, and pre-gestational diabetes. Excluding women with preeclampsia, antenatal bleeding, and SGA.
[29] 90,165 Dk    MR, TSR NSNNU, smoking, NRT, dual-use SB For the NRT groups: smoking, Maternal age, SES. Excluded: Multiple births, pregnancies ending in hydatidiform mole or ectopic pregnancy, or before 20 completed weeks.
[30] 220,630 UK    MR, SR Never-smoked, RecNRT, smoking SB Maternal age, SES, pre-pregnancy BMI, and diabetes. Excluded multi-births
[31] 76,768 Dk    MR, SR NSNNU, smoking, NRT MF Not specified for NRT group
[32] 192,498 UK    MR, SR NSNNU, smoking, RecNRT MF Age, SES, maternal diabetes, asthma, mental illnesses, and multiple births. Excluding: SB
[41] 975,866 Sw    MR, SR NSNNU, smoking, snus MF age, parity, education, living with father-to-be, hypertension, diabetes, PE, sex of newborn, birth (singleton or multiple)
[33] 63,128 Dk    TSR NRT, NSNNU, smoking Colic Maternal age, parity, daily coffee consumption, weekly alcohol consumption, binge-drinking, and education and SES
Cross-sectional non-population-based studies
[44] 129     MR Vaping BW, PT Not specified
[34] 5716 USA White   SWQ, BC RecNRT, never-smoked, smoking BW, PT Age, PPBMI, race/ethnicity, education level, MS, income, MA, parity, alcohol, and maternal weight gain during pregnancy. Excluded: no PNC, no information on MS, MA, or alcohol
[42] 23,542 Sw    MR, SR (MWR) NSNNU, smoking, snus BW, PT, PE Maternal age, GA, BMI, parity, infant sex, excluded, multiple births, stillbirths
[45] 41 USA AN CS8 SI, LipTool NSNNU (C), Iq’mik, GA, BW, ApgS, LipTool Not stated
Prospective study
[43] 56 Sw   Pilot SR, COT Snus, NSNNU, smoking CVD BW, baby’s sex, mother’s weight, parity, gestational week at delivery, GA, and BW
Observational pilot study
[35, 36] 6 USA White Pilot PE, CV N/A All Not specified
  1. 1Location: Eng = England, Dk = Denmark, NC = Nordic countries, No = Norway, Sw = Sweden, USA = United States of America, UK = United Kingdom
  2. 2Ethnicity of majority population if given: White = classified as “white” in the publication, H = Hispanic, AN = Alaskan native
  3. 3Additional design features: Cr = cross over RCT, D_Bl = double-blind, L = longitudinal, LipTool = Lipsitz tool, NB = not blinded, Pl = placebo, Ps = prospective
  4. 4BC = birth certificate, BP = blood pressure, CO = carbon monoxide reading, CR = cotinine (urine or hair) reading, MR = medical records, MWR = midwives records, SI = scientifically structured interviews, SR = self-report (without verification or with non-scientific interviewers), SWQ = self-completed written questionnaire, TSR = telephone self-reports
  5. 5Comparison groups: CBT = cognitive behavioural therapy, Combined-NRT = more than 1 NRT, ExS = smokers who quit smoking and did not use any nicotine products while pregnant, N/A = not applicable, NSNNU = no smoking no nicotine use, RecNRT = recommended to use NRT
  6. 6Outcome measures: ApgS = APGAR score, BW = birth weight, CD = caesarean delivery, CV = cardiovascular, GA = gestational age, MF = malformations, NAp = neonatal apnea, PE = preeclampsia, PT = preterm delivery, SB = still birth, SGA = small for gestational age
  7. 7Stating all the variables they adjusted for MA = medicaid, MS = marital status, PP = planned pregnancy, PPBMI = pre-pregnancy BMI, PSS = partner’s smoking status, SES = socioeconomic status, YrsEd = years of education
  8. 8Referred to as a “nonrandomized, clinical observational pilot trial”; however, because the study did not include an intervention, it has been classified as a cross-sectional study