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268 March 8, 1982 Cigarette Smoking of Pregnant Women A note regarding the "Comprehensive Smoking Prevention Education Act of 1982" HR 5653 S. 1929 My name is Bea J. van den Berg. Currently I am director of the Child Health and Development Studies, a research unit of the School of Public Health of the University of California at Berkeley. I received my medical doctor's degree in the Netherlands and in 1965 I joined the research staff of the Child Health and Development Studies that were designed and directed by the later Dr. J. Yerushalmy, professor of Biostatistics at the University of California at Berkeley. My CV is enclosed with the copy of my statement. I am here to express my concern about the statements made in the proposed 'Smoking Prevention Education Act of 1982" regarding an increased risk of spontaneous abortion, stillbirth, premature birth, child weight deficiencies and birth defects in pregnant women who smoke. For many years I have been involved in research regarding pregnancy and pregnancy outcome, and research results do not support these statements. Our studies were among the very first to identify the lower birth weight of babies born to smoking mothers as compared with that of non- smoking mothers. However, our studies did not indicate an increased risk of abortion and still births among smoking pregnant women nor are our studies supportive of the stated increased risk of birth defects. For almost two decades, at the Child Health and Development Studies, we have studied the pregnancy outcome of women who smoked cigarettes during pregnancy, in comparison with women who never smoked or who stopped smoking before or early in their pregnancy. These studies were based on interviews, early in their pregnancies, of scme 15,000 women who were members of Kaiser Foundation Health Plan, and who enrolled in the Child Health and Development Studies. Extensive information was obtained from the medical records of the mothers during their pregnancy and delivery and from the medical records of the children from birth to at least age five. Our studies are prospective and observational; prospective because the smoking data were assembled before the outcome of the pregnancy was known. This approach avoids a possible recall bias that might occur when the mothers are interviewed after the termination of the pregnancy. An unfavorable pregnancy outcome might affect the mothers' recall of any event that occurred during her pregnancy, including smoking habits. Our studies 269 -2- are observational and not experimentalj t'. researcher, but the women themselves decic cigarettes. The women in these separate r only in their smoking habits, but also in charactenistics. This methodological pro! as the problem of self-selection, has to : compare the pregnancy outcome of women whc outcome of women who do not smoke. I would like to summarize the resulte relate to the statements concerning preqnc On birth weight. As early as in 196: increased proportion of low birth weight : smoking pregnant women as compared with tt pregnant women. The observed association relationship but it may also be influencec and non-smokers in characteristics other t indeed showed that a variety of other matc socioeconomic status, maternal age and et` association between smoking during pregna: Controlling for a number of these variabl, the birthweight of the offspring of both Yerushalmy'a later work on maternal : methodologies and designing studies to te: the alternative hypothesis that increased due to the differences between smoking anc such study evaluated the frequency of low of mothers who began smoking after the bi: that women who subsequently became smoker: low birth weight babies during the period finding cannot be explained by the causal need for a larger study to confirm or ref. On abortion and stillbirth. Our sta- week of gestation the risk of fetal death pregnant women, failed to find a differen, results, based on the pregnancy outcome o provide evidence that smoking during preg: abortion and stillbirth. On birth defects. We recently publi. of the incidence of congenital anomalies children born to women who never smoked, to women who smoked during pregnancy. Th enrolled in the Child Health and Developm. show a difference in the incidence of sev children of smoking women and children of : I to

269 -2- an ss.rntioeal ard not .>re='-aental: this signifies that not the 90.sra.r, but th. Mom.n -~e:ves decide whether or not to smoke .#&qaat... SA. ,ros.n Ln :: cs. separate groups might be different, not M;f La t.`uir saoking haL.iv, t7ut also in various other known or unknown pArs..^tsyatica. This a. ~Odclogical problem, coined by Dr. J. Yerushalmy M p,%* procl.m of s.lf-se:ac~_i-n, has to be taken into consideration if we smwear. Use pr.gnancy out_-aoe cf women who do smoke with the pregnancy Kteo.e of voo.n who do not sxke. I would like to r^-a:z.e the results of our studies to date that p/ate to the statements •-+++ce^ing pregnancy in the proposed Bill. Cn birth weight. As ear_y as in 1962 Dr. Yerushalmy reported an lecz.as.d proportion of :.,^r `:;..h weight infants among the offspring of saaxinq pregnant women as ==-a red with the offspring of non-smoking pr.y-iant women. The obse_~d association may indicate a cause-and-effect r.lationship but it may a:.so be influenced by differences between smokers ar.: -ten-smoKers in chara=e=s-.ics other than smoking. A later study lyd.ad showed that a var-=ety of other maternal characteristics, such as socioeconomic status, ma=er_a.i age and ethnic background, influence the association between szti;ci..^g during pregnancy and birthweight of offspring. Cantrollir.g for a number =f -_"nese variables reduces the crude difference in the birthweight of the ofsr-i.ng of both groups of women. Terushalmy's later work on maternal smoking was aimed at developing rtlvdologies and desigm_i-mg studies to test the causal hypothesis against the alternative hypothesis that inceased incidence of low birth weight is due to the differences :De:+ee.n smoking and non-smoking pregnant women. • One .uch study evaluated the f--e:,uency of low birth weight among the offspring of mothers who began smo<<-g after the birth of the infants. It was found that women who subsequently became smokers also had a high incidence of low birth weight babies durirg the period before they started to smoke. This finding cannot be explained by the causal hypothesis and underscores the need for a larger study to confirm or refute this finding. On abortion and stillbi--,.h. Our statistical study, comparing for each week of gestation the risk of fetal death for smoking and non-smoking pregnant women, failed to find a difference between the two groups. These results, based on the pregnancy outcome of 15,000 pregnant women, do not provide evidence that smokinq during pregnancy raises the risk of spontaneous abortion and stillbirth. On birth defects. We recently published the results of our evaluation of the incidence of congenital anomalies (or birth defects) among the 14,735 children born to women who never smoked, to women who were past smokers or to women who smoked during pregnancy. The children were offspring of mothers enrolled in the Child Sealth and Development Studies. Our data did not show a difference in the incidence of severe congenital anomalies among children of smoking women and children of women who never smoked. We also T

270 -3- ]qoked at the incidents of non-severe congenital anomalies. We found that, while the incidence of these non-severe birth defects among children of h.avy smokers (more than 20 cigarettes per day) was slightly more than among children of non-smokexs, the incidence among children our light smokers (less than 20 cigarettes per day) was equal to that of the children of non-smokers. These observations, again, do not support the statement in the proposed Bill that cigarette smoking by pregnant women may result in birth defects. In conclusion, our data do not support the statements in the proposed Bill. 'tc 27 PETER L. 4 Worthinc Brookline, M Tel. (617) I am a sociologist, cur Boston University. The following does not necessarily represent tYh which I am affiliated. (A brief My attention was first by an article in the New York T subsequently obtained the texts o my opinion, constitute a further for some time now, interested me me as a citizen; that is, the anti-smoking movement and its a• smoking activity. I have no comaetence questions at issue. However, I c to the broader social and culture and it seems to me that it rai: questions about the scope and pu- on which any citizen has the righ What first interested aggressiveness with which anti-s their campaign. It annoyed me a should say that I smoke cigars ar. are the major targets of the anti