title: Interplay between maternal weight and seasons in determining the secondary sex ratio of human offspring.
abstract: When gender of 9,284 single fetuses, which were delivered at term in the Policlinic of Modena between 1997-2001, was stratified for month of conception and for quartiles of pregravid maternal weight, it showed that the ratio of male to female fetuses (secondary sex ratio) was characterized by a clear seasonal variation that was modulated by pregravid maternal weight. Two seasonal peaks of sex ratio (March and October +/- 31 days) were observed in mothers in the lowest two quartiles of prepregnancy body weight (< or =62 kg), and one single peak (October +/-36 days) was observed in mothers with preconception weight in the upper two quartiles.
authors: Department of Obstetrics, Gynaecology, and Pediatrics, Policlinico of Modena, Modena, Italy. cagnacci@unimore.it
authors: Angelo
authors: A
authors: Cagnacci
authors: Antonietta
authors: A
authors: Renzi
authors: Serenella
authors: S
authors: Arangino
authors: Chiara
authors: C
authors: Alessandrini
authors: Annibale
authors: A
authors: Volpe
mesh_terms: D000328:Adult; D001835:Body Weight / Q000502:physiology*; D016009:Chi-Square Distribution; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D010507:Periodicity; D011247:Pregnancy; D012621:Seasons; D012744:Sex Ratio