Endometrial: Endometrial causes of abnormal bleeding include infection of the endometrium, endometritis, which may occur after a miscarriage (spontaneous abortion) or a delivery, or may be related to a sexually-transmitted infection of the uterus, fallopian tubes or pelvis generally termed pelvic inflammatory disease (PID). Other endometrial causes of abnormal bleeding may relate to the ways that the endometrium heals itself or develops blood vessels. Iatrogenic (caused by medical treatment or procedures): The most common Iatrogenic cause of abnormal bleeding relates to treatment with hormonal medications such as birth control pills, patches, rings, injections, implants, and intrauterine devices (IUDs). Hormone therapy for treatment of menopausal symptoms can also cause abnormal bleeding. Unscheduled bleeding that occurs during such hormonal treatment is termed "breakthrough bleeding" (BTB)  Breakthrough bleeding may result from inconsistent use of hormonal treatment, although in the initial months after initiation of a method, it may occur even with perfect use, and may ultimately affect adherence to the medication regimen. The risk of breakthrough bleeding with oral contraceptives is greater if pills are missed. Not classified: The Not Classified category of the PALM-COEIN system includes conditions that may be rare, or whose contribution to abnormal bleeding has not been well established or understood. Pregnancy
Vaginal bleeding occurs during 15–25% of first trimester pregnancies. Of these, half go on to miscarry and half bring the fetus to term. There are a number of causes including complications to the placenta, such as placental abruption and placenta previa.
Toxic amblyopia, or nutritional optic neuropathy, is a condition where a toxic reaction in the optic nerve results in visual loss. Various poisonous substances may cause the condition as well as nutritional factors.Tobacco amblyopia is a form of toxic amblyopia caused by tobacco containing cyanide. Tobacco amblyopia is marked by a gradual impairment of vision characterised by visual field defects and hindered central vision. Methyl alcohol amblyopia occurs through acute poisoning by methyl alcohol and may lead to complete blindness. Since the term toxic amblyopia is a misnomer according to modern definition of amblyopia, it is now more accurately termed as toxic retinopathies or neuropathies. == References ==