title: Sex differences in birth size and intergenerational effects of intrauterine exposure to Ramadan in Saudi Arabia.
abstract: OBJECTIVE
  In Europe, boys and girls have different body proportions at birth. We examined newborn babies in Saudi Arabia to determine the sex differences and whether fetal growth differed if the mother was in utero during Ramadan.
  
  
  METHODS
  We examined body size at birth among 967 babies (479 boys and 488 girls) born in Unizah, a small city in Saudi Arabia.
  
  
  RESULTS
  Large head circumference was the strongest single predictor of male sex. In a simultaneous regression, female sex was predicted by small head circumference (P < 0.001), low birth weight (P = 0.002), and large chest circumference (P = 0.008). The mothers of boys were heavier in pregnancy than the mothers of girls and had a higher body mass index, 31.7 kg/m(2) compared to 30.2 (P < 0.001). The mothers of girls, however, were taller than the mothers of boys, 158.6 cm compared to 157.4 (P = 0.001). Compared to babies whose mothers were not in utero during Ramadan boys whose mothers were in mid gestation during Ramadan were 1.2 cm longer (P = 0.005) while girls had a 0.4 week shorter gestation period (P = 0.04).
  
  
  CONCLUSIONS
  Our findings are consistent with other evidence that boys are more ready than girls to trade off visceral development in utero to protect somatic and brain growth. They also support the hypothesis that boys are more responsive to their mother's current diet than girls, who respond more to their mother's life time nutrition and metabolism. They provide the first evidence that changes in the life style of pregnant women during Ramadan affect more than one generation.
authors.affiliation: Fetal Programming of Disease' Research Chair, Zoology Department, College of Science, King Saud University, Saudi Arabia.
authors.forename: S H
authors.initials: SH
authors.lastname: Alwasel
authors.forename: Z
authors.initials: Z
authors.lastname: Abotalib
authors.forename: J S
authors.initials: JS
authors.lastname: Aljarallah
authors.forename: C
authors.initials: C
authors.lastname: Osmond
authors.forename: S M
authors.initials: SM
authors.lastname: Alkharaz
authors.forename: I M
authors.initials: IM
authors.lastname: Alhazza
authors.forename: A
authors.initials: A
authors.lastname: Harrath
authors.forename: K
authors.initials: K
authors.lastname: Thornburg
authors.forename: D J P
authors.initials: DJ
authors.lastname: Barker
mesh_terms: D000328:Adult; D001724:Birth Weight; D049628:Body Size; D002508:Cephalometry; D005215:Fasting; D005260:Female; D047109:Fetal Development; D006801:Humans; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D007514:Islam; D008297:Male; D016017:Odds Ratio; D011247:Pregnancy / Q000502:physiology*; D012529:Saudi Arabia; D012727:Sex Characteristics