Biomaterial Database

Preterm birth and maternal smoking: risks related to gestational age and onset of delivery. 1998

N B Kyrklund-Blomberg, and S Cnattingius

Division of Obstetrics and Gynaecology, Danderyd Hospital, Karolinska Institutet, Stockholm, Sweden.

OBJECTIVE The object was to examine the effects of smoking on spontaneous and induced very and moderately preterm birth (< or = 32 and 33-36 completed weeks' gestation, respectively). METHODS Live singleton births in Sweden, 1991-1993 (n = 311,977), were examined. RESULTS Risk of preterm birth consistently increased with amount smoked. Smoking was most heavily associated with increased risks of very preterm birth and spontaneous preterm birth. The highest impact of smoking was seen on risk of spontaneous very preterm birth among women who smoked at least 10 cigarettes/d (odds ratio 1.7). The smoking-related risks of preterm birth remained essentially unchanged after excluding pregnancies with smoking-associated pregnancy complications. CONCLUSIONS There is a dose-related impact of smoking on risk of preterm birth. The fact that the smoking-related risk of spontaneous preterm birth is more pronounced than that of induced preterm birth suggests that smoking is associated with spontaneous preterm labor.

UI	MeSH Term	Description	Entries
D007743	Labor, Obstetric	The repetitive uterine contraction during childbirth which is associated with the progressive dilation of the uterine cervix (CERVIX UTERI). Successful labor results in the expulsion of the FETUS and PLACENTA. Obstetric labor can be spontaneous or induced (LABOR, INDUCED).	Obstetric Labor
D007751	Labor, Induced	Artificially induced UTERINE CONTRACTION.	Induced Labor,Induction of Labor,Labor Induced,Labor Induction,Induced, Labor,Induction, Labor,Inductions, Labor,Labor Inductions
D007752	Obstetric Labor, Premature	Onset of OBSTETRIC LABOR before term (TERM BIRTH) but usually after the FETUS has become viable. In humans, it occurs sometime during the 29th through 38th week of PREGNANCY. TOCOLYSIS inhibits premature labor and can prevent the BIRTH of premature infants (INFANT, PREMATURE).	Preterm Labor,Labor, Premature,Premature Labor,Premature Obstetric Labor,Labor, Premature Obstetric,Labor, Preterm
D008423	Maternal Age	The age of the mother in PREGNANCY.	Age, Maternal,Ages, Maternal,Maternal Ages
D010298	Parity	The number of offspring a female has borne. It is contrasted with GRAVIDITY, which refers to the number of pregnancies, regardless of outcome.	Multiparity,Nulliparity,Primiparity,Parity Progression Ratio,Parity Progression Ratios,Ratio, Parity Progression,Ratios, Parity Progression
D010923	Placenta Previa	Abnormal placentation in which the PLACENTA implants in the lower segment of the UTERUS (the zone of dilation) and may cover part or all of the opening of the CERVIX. It is often associated with serious antepartum bleeding and PREMATURE LABOR.	Placenta Praevia
D011247	Pregnancy	The status during which female mammals carry their developing young (EMBRYOS or FETUSES) in utero before birth, beginning from FERTILIZATION to BIRTH.	Gestation,Pregnancies
D005260	Female		Females
D005317	Fetal Growth Retardation	Failure of a FETUS to attain expected GROWTH.	Growth Retardation, Intrauterine,Intrauterine Growth Retardation,Fetal Growth Restriction,Intrauterine Growth Restriction
D005322	Fetal Membranes, Premature Rupture	Spontaneous tearing of the membranes surrounding the FETUS any time before the onset of OBSTETRIC LABOR. Preterm PROM is membrane rupture before 37 weeks of GESTATION.	Premature Rupture of Membrane (Pregnancy),PROM (Pregnancy),Premature Rupture of Fetal Membranes,Preterm PROM (Pregnancy),Preterm Premature Rupture of Fetal Membranes,Membrane Premature Rupture (Pregnancy),Membrane Premature Ruptures (Pregnancy),PROM, Preterm (Pregnancy)