Maternal smoking during pregnancy and possible effects of in utero testosterone: Evidence from the 2D:4D finger length ratio

• Published in: Early human development Vol. 83; no. 2; pp. 87 - 90
• Main Authors: Rizwan, S, Manning, J.T, Brabin, B.J
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier Ireland Ltd 01.02.2007; New York,NY Elsevier; Amsterdam
• Subjects: 2D:4DL; Advanced Basic Science; Analysis of Variance; Biological and medical sciences; Body Weights and Measures; Child; Embryology: invertebrates and vertebrates. Teratology; England; Female; Finger length; Fingers - anatomy & histology; Fundamental and applied biological sciences. Psychology; Humans; Male; Maternal Exposure; Neonatal and Perinatal Medicine; Pregnancy; Sex Factors; Smoking; Surveys and Questionnaires; Testosterone; England; Pregnancy; Finger length; Testosterone; Smoking; 2D:4DL; Human; Androgen; Finger; Tobacco smoking; In utero; Ratio; Testicular hormone; Sex steroid hormone
• ISSN: 0378-3782; 1872-6232
• DOI: 10.1016/j.earlhumdev.2006.05.005

Abstract Objectives Maternal smoking during pregnancy is linked to high fetal testosterone (FT), and an increased risk in offspring for autism, ADHD, conduct disorder, antisocial behaviour and criminal outcomes. The ratio of the length of the 2nd and 4th fingers (2D:4D) is thought to be negatively related to FT concentration, and is related to autism, hyperactivity, poor social behaviour, and physical aggression. We compare the 2D:4D ratio of children whose mothers smoked during pregnancy with the 2D:4D of children whose mother did not smoke. Method Cross-sectional survey in two primary schools. Questionnaires were distributed to 710 children and 546 were returned. Of these the 2nd and 4th digits of 520 children (259 females and 261 males) were measured. The main outcome measures were 2nd and 4th digit length, smoking history of mother and father. Results Boys had lower mean 2D:4D than girls and right 2D:4D was lower than left. Among boys, those whose mother's smoked during pregnancy had lower right hand 2D:4D ratio than those whose mother did not smoke. The difference remained significant after the effects of age, height, weight and birth weight were removed. Other household smoking patterns were not associated with male offspring 2D:4D. Female offspring 2D:4D did not differ on the basis of maternal smoking. Conclusions Maternal smoking during pregnancy was associated with low right 2D:4D in children, but the effect was restricted to boys. A link between maternal smoking during pregnancy and 2D:4D supports a causal association between FT and such behaviours as hyperactivity and conduct disorder.