PLoS Medicine (Aug 2020)

Changes in parental smoking during pregnancy and risks of adverse birth outcomes and childhood overweight in Europe and North America: An individual participant data meta-analysis of 229,000 singleton births.

  • Elise M Philips,
  • Susana Santos,
  • Leonardo Trasande,
  • Juan J Aurrekoetxea,
  • Henrique Barros,
  • Andrea von Berg,
  • Anna Bergström,
  • Philippa K Bird,
  • Sonia Brescianini,
  • Carol Ní Chaoimh,
  • Marie-Aline Charles,
  • Leda Chatzi,
  • Cécile Chevrier,
  • George P Chrousos,
  • Nathalie Costet,
  • Rachel Criswell,
  • Sarah Crozier,
  • Merete Eggesbø,
  • Maria Pia Fantini,
  • Sara Farchi,
  • Francesco Forastiere,
  • Marleen M H J van Gelder,
  • Vagelis Georgiu,
  • Keith M Godfrey,
  • Davide Gori,
  • Wojciech Hanke,
  • Barbara Heude,
  • Daniel Hryhorczuk,
  • Carmen Iñiguez,
  • Hazel Inskip,
  • Anne M Karvonen,
  • Louise C Kenny,
  • Inger Kull,
  • Debbie A Lawlor,
  • Irina Lehmann,
  • Per Magnus,
  • Yannis Manios,
  • Erik Melén,
  • Monique Mommers,
  • Camilla S Morgen,
  • George Moschonis,
  • Deirdre Murray,
  • Ellen A Nohr,
  • Anne-Marie Nybo Andersen,
  • Emily Oken,
  • Adriëtte J J M Oostvogels,
  • Eleni Papadopoulou,
  • Juha Pekkanen,
  • Costanza Pizzi,
  • Kinga Polanska,
  • Daniela Porta,
  • Lorenzo Richiardi,
  • Sheryl L Rifas-Shiman,
  • Nel Roeleveld,
  • Franca Rusconi,
  • Ana C Santos,
  • Thorkild I A Sørensen,
  • Marie Standl,
  • Camilla Stoltenberg,
  • Jordi Sunyer,
  • Elisabeth Thiering,
  • Carel Thijs,
  • Maties Torrent,
  • Tanja G M Vrijkotte,
  • John Wright,
  • Oleksandr Zvinchuk,
  • Romy Gaillard,
  • Vincent W V Jaddoe

DOI
https://doi.org/10.1371/journal.pmed.1003182
Journal volume & issue
Vol. 17, no. 8
p. e1003182

Abstract

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BackgroundFetal smoke exposure is a common and key avoidable risk factor for birth complications and seems to influence later risk of overweight. It is unclear whether this increased risk is also present if mothers smoke during the first trimester only or reduce the number of cigarettes during pregnancy, or when only fathers smoke. We aimed to assess the associations of parental smoking during pregnancy, specifically of quitting or reducing smoking and maternal and paternal smoking combined, with preterm birth, small size for gestational age, and childhood overweight.Methods and findingsWe performed an individual participant data meta-analysis among 229,158 families from 28 pregnancy/birth cohorts from Europe and North America. All 28 cohorts had information on maternal smoking, and 16 also had information on paternal smoking. In total, 22 cohorts were population-based, with birth years ranging from 1991 to 2015. The mothers' median age was 30.0 years, and most mothers were medium or highly educated. We used multilevel binary logistic regression models adjusted for maternal and paternal sociodemographic and lifestyle-related characteristics. Compared with nonsmoking mothers, maternal first trimester smoking only was not associated with adverse birth outcomes but was associated with a higher risk of childhood overweight (odds ratio [OR] 1.17 [95% CI 1.02-1.35], P value = 0.030). Children from mothers who continued smoking during pregnancy had higher risks of preterm birth (OR 1.08 [95% CI 1.02-1.15], P value = 0.012), small size for gestational age (OR 2.15 [95% CI 2.07-2.23], P value ConclusionsWe observed that as compared to nonsmoking during pregnancy, quitting smoking in the first trimester is associated with the same risk of preterm birth and small size for gestational age, but with a higher risk of childhood overweight. Reducing the number of cigarettes, without quitting, has limited beneficial effects. Paternal smoking seems to be associated, independently of maternal smoking, with the risk of childhood overweight. Population strategies should focus on parental smoking prevention before or at the start, rather than during, pregnancy.