Abstract
Background: Studies examining the adverse effects of smoking during pregnancy commonly use maternal reports. We hypothesized that if an adverse event occurred during pregnancy, women may underreport smoking. This study looked for bias in maternal report of smoking if fetal distress occurs.
Methods: Data were collected prospectively from patients attending The MotheRisk Program who smoked during pregnancy, and were categorized by delivery outcome, maternal and neonatal characteristics, and the raw number of cigarettes smoked per day during pregnancy reported at clinic and at follow-up. The difference between these two values was compared.
Results: 95 women had uneventful deliveries and 25 had fetal distress. Women who reported fetal distress decreased their report of smoking after delivery compared to their original report during pregnancy, whereas women with an uneventful labour did not (p=0.04).
Conclusions: Our results suggest that if an adverse pregnancy outcome occurs, mothers may tend to underreport their cigarette consumption.
Résumé
Contexte: Les études des effets néfastes du tabac pendant la grossesse emploient communément les déclarations des mères. Nous avons supposé qu’en cas de réaction adverse durant la grossesse, les femmes pourraient avoir tendance à minimiser le degré de leur tabagisme. Notre étude visait à détecter un biais dans les déclarations, par les mères, de leur utilisation du tabac en cas de détresse foetale.
Méthode: Nous avons recueilli des données à des fins prospectives auprès de patientes du programme MotheRisk qui fumaient pendant leur grossesse, puis classé ces données en fonction du résultat de l’accouchement, des caractéristiques de la mère et du nouveau-né, ainsi que du nombre de cigarettes fumées par jour pendant la grossesse, selon les déclarations des mères à la clinique et lors du suivi. Nous avons ensuite comparé les écarts entre ces deux derniers chiffres.
Résultats: 95 femmes ont signalé un accouchement sans problème, et 25 un accouchement avec détresse foetale. Ces dernières ont fait état d’une moindre utilisation de la cigarette après l’accouchement que durant la grossesse. Pour les femmes ayant accouché sans problème, le degré de tabagisme déclaré est resté le même.
Conclusions: Nos résultats suggèrent que lorsqu’une réaction adverse se manifeste à l’issue d’une grossesse, les mères auraient tendance à minimiser leur degré de tabagisme.
Footnotes
Supported in part by the Medical Research Council of Canada, and the Seed Grant Program, The Hospital for Sick Children.
References
- 1.Jedrychowski W, Whyatt RM, Cooper TB, et al. Exposure misclassification error in studies on prenatal effects of tobacco smoking in pregnancy and the birth weight of children. J Exposure Analysis & Environment Epidemiol. 1998;8(3):347–57. [PubMed] [Google Scholar]
- 2.Klebanoff MA, Levine RJ, Clemens JD, et al. Serum cotinine concentration and self-reported smoking during pregnancy. Am J Epidemiol. 1998;148(3):259–62. doi: 10.1093/oxfordjournals.aje.a009633. [DOI] [PubMed] [Google Scholar]
- 3.Murray RP, Connett JE, Lauger GG, Voelker HT. Error in smoking measures: Effects of intervention on relations of cotinine and carbon monoxide to self-reported smoking. The Lung Health Study Research Group. Am J Public Health. 1993;83(9):1251–57. doi: 10.2105/AJPH.83.9.1251. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 4.Walsh RA, Redman S, Adamson L. The accuracy of self-report of smoking status in pregnant women. Addictive Behav. 1996;21(5):675–79. doi: 10.1016/0306-4603(95)00097-6. [DOI] [PubMed] [Google Scholar]
- 5.Welte JW, Russell M. Influence of socially desirable responding in a study of stress and substance abuse. Alcoholism, Clinical & Experimental Res. 1993;17(4):758–61. doi: 10.1111/j.1530-0277.1993.tb00836.x. [DOI] [PubMed] [Google Scholar]
- 6.DiFranza JR, Lew RA. Effect of maternal cigarette smoking on pregnancy complications and sudden infant death syndrome. J Fam Practice. 1995;40(4):385–94. [PubMed] [Google Scholar]
- 7.Walsh RA. Effects of maternal smoking on adverse pregnancy outcomes: Examination of the criteria of causation. Human Biology. 1994;66(6):1059–92. [PubMed] [Google Scholar]
- 8.Haslam C, Draper ES, Goyder E. The pregnant smoker: A preliminary investigation of the social and psychological influences. J Public Health Med. 1997;19(2):187–92. doi: 10.1093/oxfordjournals.pubmed.a024607. [DOI] [PubMed] [Google Scholar]
- 9.Hill LM. Diagnosis and management of fetal distress. Mayo Clinic Proceedings. 1979;54(12):784–93. [PubMed] [Google Scholar]
- 10.Parer JT, Livingston EG. What is fetal distress? Am J Obstet Gynecol. 1990;162(6):1421–25. doi: 10.1016/0002-9378(90)90901-I. [DOI] [PubMed] [Google Scholar]
- 11.Mead M. The diagnosis of foetal distress: a challenge to midwives. J Adv Nurs. 1996;23(5):975–83. doi: 10.1046/j.1365-2648.1996.09917.x. [DOI] [PubMed] [Google Scholar]
- 12.Gilstrap L, Leveno KJ, Burris J, et al. Diagnosis of birth asphyxia on the basis of fetal pH, Apgar score, and newborn cerebral dysfunction. Am J Obstet Gynecol. 1989;161:825–30. doi: 10.1016/0002-9378(89)90410-9. [DOI] [PubMed] [Google Scholar]
- 13.Feldman Y, Koren G, Mattice K, et al. Determinants of recall and recall bias in studying drug and chemical exposure in pregnancy. Teratology. 1989;40(1):37–45. doi: 10.1002/tera.1420400106. [DOI] [PubMed] [Google Scholar]
- 14.Neutra RR, Swan SH, Hertz-Picciotto J, et al. Potential sources of bias and confounding in environmental epidemiologic studies of pregnancy outcomes. Epidemiology. 1992;3(2):134–42. doi: 10.1097/00001648-199203000-00012. [DOI] [PubMed] [Google Scholar]
- 15.Seaton MJ, Vesell ES. Variables affecting nicotine metabolism. Pharmacology & Therapeutics. 1993;60(3):461–500. doi: 10.1016/0163-7258(93)90032-9. [DOI] [PubMed] [Google Scholar]