<prompt> NOT a definitive sign of pregnancy:Fetal skeleton on X-rayFetal hea soundsUltrasound examinationAmenorrhea  <response>: Amenorrhea can be due to many reasons including pregnancy but also PCOS, Tuberculosis, Hypothalamic causes like Kallmans Sheehans syndrome , Pseudocyesis etc Remaining 3 are the definite signs of Pregnancy 