B. Zaren et al., HEMOCONCENTRATION IN SMOKING MOTHERS IS ASSOCIATED WITH IMPAIRED FETAL GROWTH, Acta obstetricia et gynecologica Scandinavica, 76(10), 1997, pp. 933-941
Objective. To examine the effect of maternal smoking on the relationsh
ip between maternal hemoglobin levels and pregnancy outcome. Design. A
prospective study of healthy parous women from early pregnancy and of
their infants. Setting. Three Scandinavian university hospitals cover
ing all deliveries from well defined,geographical areas. Subjects. Smo
king (669) and non-smoking (368) mothers, para 1 and 2 and with greate
r than or equal to 37 weeks of gestational length. Main outcome measur
es. Birth weight and placental weight. Ponderal Index and Placental In
dex as measures of possible discordant fetal and placental growth. Res
ults. In non-smoking mothers the hemoglobin levels in the three trimes
ters had no relation to birth weight. In smoking mothers a significant
ly lower birth weight was seen with a high hemoglobin level in the thi
rd trimester, but hemoglobin levels in early or mid-pregnancy had no a
ssociation to birth weight. Smoking mothers also had a significantly g
reater fall in hemoglobin concentration from first to second and third
trimester as compared to nonsmokers although ferritin levels were sim
ilar in smokers and non-smokers, implying similar iron stores. The rat
io of placental weight to the weight of the newborn was significantly
higher in smokers, but no association was found to different hemoglobi
n levels. Conclusions. Fetal growth impairment associated with materna
l smoking is even more pronounced in smoking mothers with high hemoglo
bin levels in late pregnancy. Smoking mothers were also found to have
disproportional fetal/placental growth with relatively high placental
weights. In non-smoking mothers hemoglobin levels had no relation to b
irthweight.