Relationship between Digit Ratio (2D:4D) and Birth Weight in Nigerians

Digit ratio (2D:4D) as an indicator of body size, testosterone concentration and number of children in human males

“…A similar relationship was shown in a sample of British men among whom low 2D:4D was related to higher birth length (Ronalds et al, 2002) and in a sample of Nigerian men where low 2D:4D was related to higher birth weight (Danborno et al, 2010). This may be due to a role of testosterone in determining body composition, especially its positive impact on somatic growth (Danborno et al, 2010) and development of lean body mass (Schroeder et al, 2012). Higher body mass and higher BMI (calculated as z-score) among children and adolescents with low 2D:4D (borderline significance for BMI) was observed.…”

“…Vermeulen et al, 1999). It should also be noted that high testosterone levels may accelerate foetal growth and, thus, result in higher birth weight and length, but the positive role of oestrogen also should be taken into account (Danborno et al, 2010;Frank, 2003). Moreover, a relationship between 2D:4D and birth size can also be expected, since it is hypothesized that both these traits are pre-natally programmed (Voracek, 2009).…”

“…These Hox genes are responsible for differentiation of both the digits and the urinogenital system simultaneously , although this hypothesis still requires confirmation (Medland et al, 2010). Digit ratio (as a possible marker of pre-natal sex hormone levels) has been reported to correlate with male birth size (Danborno et al, 2010;McIntyre et al, 2006;Ronalds et al, 2002), adult body size (Fink et al, 2003;Van Dongen, 2009) and family size . However, some other studies have not confirmed these relationships (for a review see: Putz et al, 2004).…”

Family effects on the digit ratio (2D:4D): The role of the interbirth interval

“…Increasing differences between siblings with decreasing IBI below the expected evolutionary norm/optimum for our species (3‐4 years) indicates that some kind of stress might be imposed on the affected (subsequent order) fetuses, even in nutritionally and medically well supplemented populations, and that the stress is followed with some changes in the digit development. The prenatal stress explanation of sex‐atypical digit ratios might also be applied to some previous results, for example, lowered 2D:4D ratio in females with coronary artery disease (Wang et al, ) or high 2D:4D ratio in men with shorter neonatal crown‐heel length (Ronalds, Phillips, Godfrey, & Manning, ) or low birth weight (Danborno, Adebisi, Adelaiye, & Ojo, ). Whether the possible stress effect of short IBI is mediated by prenatal sex hormones remains a question.…”

Digit ratio (2D:4D): A Potential Anatomical Biomarker for Predicting the risk of development of Polycystic Ovarian Syndrome

“…The digit ratio has also been associated by many authors with several characteristics such as congenital adrenal hyperplasia [10,29], developmental psychopathology, Autism and Aspergers syndrome [30], Down's syndrome [1], Physical aggression [31], Sperm counts [7,32], family size [33], age at myocardial infarction [34], good visualspatial ability [35], late menarche and time to pregnancy [36], eating disorders [37], fetal growth and birth weight [38][39][40], alcohol dependency [41], breast cancer [42][43], and prostate cancer risk [44][45]. Women with congenital adrenal hyperplasia who are genetically programmed to produce in utero androgens have masculine finger length patterns [10], commonly exhibit a PCOS-like syndrome with hypersecretion of luteinizing hormone and ovarian hyperandrogenism, suggesting prenatal testosterone excess as a possible PCOS etiology [46].…”