title: Letter: Where have all the conceptions gone?
mesh_terms: D000022:Abortion, Spontaneous / Q000145:classification / Q000209:etiology*; D000013:Congenital Abnormalities / Q000209:etiology; D004622:Embryo, Mammalian; D005260:Female; D005306:Fertilization; D006801:Humans; D006828:Hydatidiform Mole / Q000150:complications; D011247:Pregnancy