The authors examined the association between exposure to tobacco smoke in utero and the risk of stillbirth and infant death in a cohort of 25,102 singleton children of pregnant women scheduled to deliver at Aarhus University Hospital, Aarhus, Denmark, from September 1989 to August 1996. Exposure to tobacco smoke in utero was associated with an increased risk of stillbirth (odds ratio = 2.0, 95% confidence interval: 1.4, 2.9), and infant mortality was almost doubled in children born to women who had smoked during pregnancy compared with children of nonsmokers (odds ratio = 1.8, 95% confidence interval: 1.3, 2.6). Among children of women who stopped smoking during the first trimester, stillbirth and infant mortality was comparable with that in children of women who had been nonsmokers from the beginning of pregnancy. Conclusions were not changed after adjustment in a logistic regression model for the sex of the child; parity; or maternal age, height, weight, marital status, years of education, occupational status, and alcohol and caffeine intake during pregnancy. Approximately 25% of all stillbirths and 20% of all infant deaths in a population with 30% pregnant smokers could be avoided if all pregnant smokers stopped smoking by the sixteenth week of gestation.
BACKGROUND: Previous studies have indicated that the risk of stillbirth is increased in singleton pregnancies achieved after assisted reproduction technology (ART). However, no previous study fully accounted for factors with potential influence on the risk of stillbirth. Further, whether fertility treatment, the possible reproductive pathology of the infertile couples or other characteristics related to being subfertile may explain a possible association with stillbirth remains unclear. This study compares the risk of stillbirth in women pregnant after fertility treatment (IVF/ICSI and non-IVF ART) and subfertile women with that in fertile women. METHODS: We used prospectively collected data from the Aarhus Birth Cohort, Denmark and included information about 20 166 singleton pregnancies (1989-2006). Outcome measure was stillbirth. RESULTS: The risk of stillbirth in women who conceived after IVF/ICSI was 16.2 per thousand ( per thousand) and in women who conceived after non-IVF ART 2.3 per thousand. In fertile and subfertile women, the risk of stillbirth was 3.7 per thousand and 5.4 per thousand, respectively. Compared with fertile women, women who conceived after IVF/ICSI had more than four times the risk of stillbirth [odds ratio (OR): 4.44, 95% confidence interval (CI): 2.38-8.28], and adjustments for maternal age, BMI, education, smoking habits and alcohol and coffee intake during pregnancy had only minor impact on the findings (OR: 4.08; 95% CI: 2.11-7.93). The risk of stillbirth in women who conceived after non-IVF ART and in women who conceived spontaneously with a waiting time to pregnancy of a year or more was not significantly different from the risk in women with a shorter time to pregnancy. CONCLUSIONS: Compared with fertile women, women who conceived by IVF/ICSI had an increased risk of stillbirth that was not explained by confounding. Our results indicate that the increased risk of stillbirth seen after fertility treatment is a result of the fertility treatment or unknown factors pertaining to couples who undergo IVF/ICSI.
BACKGROUND: A twin pregnancy imposes greater demands on maternal physiology and smoking may thus be associated theoretically with a greater risk of preterm delivery than in singleton pregnancies. POPULATION AND METHODS: From 1989 to 1996 all women who booked for antenatal care at the Department of Gynecology and Obstetrics, Aarhus University Hospital, Denmark were asked to fill in two questionnaires. Apart from smoking habits, these questionnaires provided information on medical and obstetric history together with information on sociodemographic and other lifestyle variables. Gestational age at delivery was calculated from ultrasonographically determined fetal biparietal diameter and information about the last menstrual period. Only women carrying twins were included in the present study (n=401). RESULTS: Mean gestational age was 5 days (95% CI 1-9 days) shorter among smokers compared with non-smokers. Among non-smokers mean gestational age was 261 days (+/-18), among women who smoked 1-9 and 10+ cigarettes per day 257 days (+/-23) and 255 days (+/-20), respectively. The overall risk of preterm delivery (
OBJECTIVES: To evaluate the effect of specific education of midwives on stopping smoking in pregnant women and to determine the effect of this programme on pregnancy outcome. DESIGN: A prospective intervention study. SETTING: Department of Gynaecology and Obstetrics, Aarhus University Hospital, Denmark. POPULATION AND METHODS: A group of midwives (9 out of 54) was taught the effects of smoking during pregnancy and instructed in various methods of educating women to stop smoking. All pregnant women who attended antenatal care from October 1994 to September 1995 were either in the intervention group (n = 527) or the control group (n = 2629). Pregnant women attending the specifically educated midwives were considered to be the intervention group. They were given individual advice about stopping smoking at the first antenatal visit at about 16 weeks of gestation and a leaflet on smoking and pregnancy. RESULTS: At the first antenatal visit at about 16 weeks of gestation, 22% of the pregnant women smoked. Between the first visit and the routine visit at 30 weeks of gestation 51 (2%) stopped smoking and 56 (2%) started smoking. No differences were found between the intervention group and the control group in the rate of stopping smoking, validated by cotinine measurements. Mean birthweight, mean gestational age and the proportion of preterm birth in the two groups were similar. CONCLUSION: Education of midwives and integration of advice about smoking cessation at a low cost in routine antenatal care failed to affect smoking habits among pregnant women.
In order to describe smoking habits among pregnant women and predictors of smoking cessation all pregnant women attending routine antenatal care from 1989 to 1991 at the Department of Obstetrics, Aarhus University Hospital, were asked to fill in questionnaires. Information about smoking habits from 8806 women revealed that 44% smoked prior to pregnancy. One fifth of the smokers stopped smoking early in pregnancy, leaving 33% women smoking during pregnancy. The strongest predictor of smoking cessation was the number of cigarettes smoked prior to pregnancy, where those that smoked the least were most likely to give up smoking. Caffeine intake, parity, years of education, and partner's smoking habits were also associated with smoking cessation whereas social status, alcohol intake, marital status, and age of the women had no influence on smoking cessation. Thus, a strategy for a smoking cessation campaign among pregnant women could be directed towards women who smoke heavily prior to pregnancy and women with a high daily intake of caffeine.
OBJECTIVE: To evaluate the association between maternal smoking during pregnancy and infantile colic (IC). METHODS: A follow-up study of singleton infants delivered by Danish mothers at the Aarhus University Hospital from May 1991 to February 1992 and still living in the municipality of Aarhus at the age of 8 months was conducted. A total of 1820 mothers and their infants were included. Self-administered questionnaires were used to collect data on smoking, other lifestyle factors, and sociodemographic variables at 16 and 30 weeks of gestation and 8 months postpartum. IC was defined in the 8-month questionnaire and based on Wessel's criteria, except that we used only the crying criterion. RESULTS: IC was seen in 10.8% of all infants. We observed a twofold increased risk of IC among infants whose mothers smoked 15 or more cigarettes per day during their pregnancy(relative risk: 2.1; 95% confidence interval: 1.4-3.2) or in the postpartum period (relative risk: 2.0; 95% confidence interval: 1.3-3.1). Women who smoked continuously during pregnancy and the postpartum period had a relative risk of 1.5 (95% confidence interval: 1.1-2.0) of having a infant with IC compared with women who did not smoke during this period. Adjustment for maternal age, parity, marital status, alcohol intake, birth weight, gestational age, breastfeeding, caffeine intake postpartum, and paternal smoking did not change the effect measures. CONCLUSION: The results indicate that maternal smoking during pregnancy may increase the risk of IC.
OBJECTIVE: To evaluate the association between smoking during pregnancy and preterm birth. DESIGN: A follow up study. SETTING: Department of Gynaecology and Obstetrics, Aarhus University Hospital, Denmark. PARTICIPANTS: Four thousand one hundred and eleven nulliparous women with singleton pregnancies who returned questionnaires about smoking habits at 16 weeks of gestation. RESULTS: The overall rate of preterm delivery was 4.3%. Smokers had a 40% higher risk of preterm birth compared with nonsmokers. A dose response relationship was found between smoking and risk of preterm birth. Adjustment for women's height, prepregnancy weight, age of the mother, marital status, education, occupational status, and alcohol intake did not change the results. Among women with an intake of less than 400 mg of caffeine per day no difference in the risk of preterm birth between smokers and nonsmokers was found. However, among women with an intake of more than 400 mg of caffeine per day, the risk of preterm birth was increased almost threefold among smokers compared with nonsmokers. Furthermore, among women with a high intake of caffeine a dose-response relationship was found; women smoking one to five cigarettes per day had no increased risk of preterm birth compared with nonsmokers with the same intake of caffeine, women smoking six to ten cigarettes per day had almost three times higher risk of preterm birth, and women smoking more than 10 cigarettes per day had almost five times higher risk of preterm birth compared with nonsmokers with the same intake of caffeine. CONCLUSIONS: Smoking increases the risk of preterm birth. The association between smoking and preterm birth was only present among women with a high intake of caffeine. However, whether smoking alone influences the risk of preterm birth among heavy consumers of caffeine needs further investigation.
BACKGROUND: The aim of the study was to describe changes in smoking habits among Danish pregnant women during an eight-year period in relation to changes in sociodemographic and lifestyle factors. METHODS: From 1989 to 1996 all pregnant women attending routine antenatal care at the Department of Gynecology and Obstetrics at Aarhus University Hospital who completed an inclusion questionnaire were invited to participate in the present study (n=27,194). They were asked to complete two additional questionnaires during pregnancy. Apart from smoking habits. these questionnaires provided information on medical and obstetric history together with information on sociodemographic and other lifestyle variables. RESULTS: The proportion of pregnant smokers decreased from 34% (95% CI: 32%/36%) in 1989 to 21% (95% CI: 19%-22%) in 1996 (p
Smoking during pregnancy is harmful to the health of the fetus and the newborn. Smoking increases the risk of low birthweight, preterm delivery and perinatal death. In developed countries smoking during pregnancy is regarded as the single most important risk factor for which it is possible to intervene. We reviewed the Scandinavian and English randomized controlled intervention studies directed towards smoking cessation during pregnancy. The intervention studies were classified according to the method of intervention namely antismoking advice, self-help manuals, measurements of smoking dependent chemical factors and multifactorial methods. We conclude that it is possible to reduce smoking during pregnancy only by an efficient and personal effort performed by a committed person towards each pregnant woman.
Comment In: Ugeskr Laeger. 1994 Nov 14;156(46):6881-27839509