Gender, smoking during pregnancy and gestational age influence cord leptin concentrations in newborn infants.
BACKGROUND
Low birth weight (BW), small head circumference, reduced length, increased preterm births and neuro-endocrine dysfunctions are among known consequences of smoking during pregnancy. Few studies have linked leptin to clinical features of growth restriction associated with maternal smoking and explored interaction with other determinants of size at birth, such as gender.


METHODS
Cord serum leptin concentrations were measured in 1215 term infants born to Caucasian mothers at completion of uneventful pregnancy. Serum concentrations were related to BW, gestational length, gender and maternal smoking and interaction with other determinants of size at birth evaluated.


RESULTS
Smoking was more frequent in younger (P<0.001) and shorter mothers (P=0.03) from lower socio-economic groups (SEGPs) (P<0.001). Infants born to smokers were lighter (190 g less), shorter and with smaller head circumference. Cord serum leptin concentrations were higher in girls (9.8 s.d. 7.6 ng/ml) than in boys (7.05 s.d. 5.8 ng/ml) (P<0.001). Boys were heavier (BW 3.52 s.d. 0.49 kg) than girls (3.39 s.d. 0.44 kg) (P<0.001), but girls had greater skinfold thickness measurements (sub-scapular and quadriceps skinfold thicknesses 5.5 s.d. 1.6 mm and 7.6 s.d. 1.9 mm respectively; boys 5.3 s.d. 1.6 vs 7.24+/-1.90 mm, P<0.001 respectively). Multivariate analyses showed gender (P<0.001), BW SDS (P<0.001), gestational length (P<0.001) and maternal smoking (P<0.042) as factors that influenced umbilical cord serum leptin concentrations in newborns.


CONCLUSIONS
Maternal smoking restrains foetal growth through placental vascular effects, and likely also via associated effects on leptin metabolism. More studies are needed to determine the influence that maternal smoking may have on placental syncytiotrophoblast and foetal adipose tissue.
Kayemba-Kay's
Simon
S
London Centre for Paediatric Endocrinology and Metabolism at Institute of Child Health, University College London, London W1T 3AA, UK.
Geary
Michael P P
MP
Pringle
Jane
J
Rodeck
Charles H
CH
Kingdom
John C P
JC
Hindmarsh
Peter C
PC
D001724:Birth Weight / Q000502:physiology; D001827:Body Height / Q000502:physiology; D005260:Female; D005312:Fetal Blood / Q000737:chemistry; D005317:Fetal Growth Retardation / Q000097:blood / Q000209:etiology / Q000503:physiopathology; D005500:Follow-Up Studies; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn / Q000097:blood*; D020738:Leptin / Q000032:analysis / Q000097:blood*; D008297:Male; D011247:Pregnancy; D011248:Pregnancy Complications / Q000097:blood / Q000209:etiology; D011297:Prenatal Exposure Delayed Effects / Q000097:blood* / Q000209:etiology; D012727:Sex Characteristics; D012907:Smoking / Q000009:adverse effects / Q000097:blood
D020738:Leptin