Wisborg K, Henriksen T B, Secher N J
Perinatal Epidemiological Research Unit, Department of Gynaecology and Obstetrics, Aarhus University Hospital, Aarhus, Denmark.
Acta Obstet Gynecol Scand. 2001 Oct;80(10):926-30. doi: 10.1034/j.1600-0412.2001.801009.x.
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.
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).
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 (< 37 weeks) and delivery before 34 completed weeks was 1.3 (95% CI 0.9-2.2) and 1.4 (95% CI 0.8-2.4), respectively. Primiparous women had shorter gestational age than did multiparous women. Still, among primiparous as well as among multiparous women gestational age decreased with smoking. Adjustment for maternal age, height and prepregnancy weight, alcohol and caffeine intake, marital status, education, occupational status, preterm birth in previous pregnancies, and in vitro fertilization in the present pregnancy did not change the results.
Smoking has a substantial effect on mean gestational age in twin pregnancies, and a dose response like relationship is present.
双胎妊娠对母体生理的要求更高，因此理论上吸烟与单胎妊娠相比，早产风险可能更高。
1989年至1996年期间，丹麦奥胡斯大学医院妇产科所有预约产前检查的女性被要求填写两份问卷。除吸烟习惯外，这些问卷还提供了医疗和产科病史信息，以及社会人口统计学和其他生活方式变量的信息。分娩时的孕周根据超声测定的胎儿双顶径和末次月经信息计算得出。本研究仅纳入怀有双胎的女性（n = 401）。
吸烟者的平均孕周比不吸烟者短5天（95%可信区间1 - 9天）。在不吸烟者中，平均孕周为261天（±18），每天吸烟1 - 9支和10支以上的女性平均孕周分别为257天（±23）和255天（±20）。早产（< 37周）和34周前分娩的总体风险分别为1.3（95%可信区间0.9 - 2.2）和1.4（95%可信区间0.8 - 2.4）。初产妇的孕周比经产妇短。然而，在初产妇和经产妇中，孕周均随吸烟量增加而缩短。对产妇年龄、身高、孕前体重、酒精和咖啡因摄入量、婚姻状况、教育程度、职业状况、既往妊娠早产史以及本次妊娠体外受精情况进行调整后，结果未改变。
吸烟对双胎妊娠的平均孕周有显著影响，且存在剂量反应关系。
