Fetal growth and the timing of exposure to maternal smoking.
BACKGROUND
Maternal smoking during the third trimester reduces the birthweight of the full-term neonate. We assessed the relationship between the timing of exposure to maternal smoking, gestational period, weight and body length for both full-term and preterm neonates.


METHODS
A retrospective study with a questionnaire was conducted in 1194 infants who participated in the official medical examination for 3-year-old infants.


RESULTS
The risk of preterm birth from mothers who smoked during any trimesters was significantly increased. The body length of neonates whose mothers smoked during the third trimester was shorter than that of neonates whose mothers did not smoke during the third trimester. The weight of full-term neonates whose mothers smoked during the third trimester was lighter than that of neonates whose mothers did not smoke during the third trimester.


CONCLUSIONS
Maternal smoking during any trimesters increased the risk of preterm birth. Maternal smoking during the third trimester reduced the body length of both full-term and preterm neonates, and the birthweight of the full-term neonate in a somewhat dose-dependent manner.
Ohmi
Hiroki
H
Health and Disease Prevention Division, Department of Health and Welfare, Hokkaido Government, N3-W6, Chuo-ku, Sapporo, Hokkaido 060-8588, Japan. hiroki.oomi@pref.hokkaido.jp
Hirooka
Kenzou
K
Mochizuki
Yoshikatsu
Y
D000328:Adult; D001724:Birth Weight; D005260:Female; D005333:Fetus / Q000502:physiology*; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D011247:Pregnancy; D011263:Pregnancy Trimester, Third; D011297:Prenatal Exposure Delayed Effects; D012907:Smoking / Q000009:adverse effects*