title: Cyclic variations in date of last menstrual period of mothers of infants with congenital malformations in South Wales, 1964-66.
mesh_terms: D001842:Bone and Bones / Q000002:abnormalities; D002675:Child, Preschool; D002972:Cleft Palate / Q000453:epidemiology; D000013:Congenital Abnormalities / Q000453:epidemiology*; D005260:Female; D005306:Fertilization; D006801:Humans; D007021:Hypospadias / Q000453:epidemiology; D008598:Menstruation; D011247:Pregnancy; D012621:Seasons; D013997:Time Factors; D014852:Wales