It is the most common cause of early pregnancy bleeding and is associated only with heavy (versus light) bleeding. However, patients typically remain hemodynamically stable. Threatened early pregnancy loss, often considered a type of early pregnancy loss, refers vaginal bleeding in the presence of an intrauterine pregnancy and a closed cervix. The presence of fetal heart rate largely determines whether the pregnancy will progress to a viable outcome. Ectopic pregnancy refers to a pregnancy outside the uterus, commonly in the fallopian tube. It is a less common but more serious cause of early pregnancy bleeding. Ectopic pregnancies can rupture, leading to internal bleeding that can be fatal if untreated. Implantation bleeding involves a small amount of bleeding that may occur 10 to 14 days after implantation of the fertilized egg. However, there is little evidence to support the existence of such bleeding. Chorionic hematoma is the pooling of blood (hematoma) between the chorion, a membrane surrounding the embryo, and the uterine wall. It occurs in about 3.1% of all pregnancies and is the most common cause of first trimester bleeding. Gestational trophoblastic neoplasia, which refers to pregnancy-related tumors that be either cancerous or non-cancerous. This cause is extremely rare with non-cancerous gestational trophoblastic neoplasia found in 23 to 1,299 cases per 100,000 pregnancies and cancerous forms with a 10-fold lower incidence.Obstetric causes of second/third trimester bleeding include the following:

Bloody show refers to the passage of a small amount of blood or blood-tinged mucus resulting from labor or cervical weakness.
Uses
Placement of a catheter into a particular part of the body may allow:

Draining urine from the urinary bladder as in urinary catheterization, using intermittent catheters or Foley catheter inserted through urethra. When the urethra is damaged, suprapubic catheterisation is used instead. The suprapubic catheter is inserted through the lower part of the abdomen directly into the urinary bladder. drainage of urine from the kidney by percutaneous (through the skin) nephrostomy
drainage of fluid collections, e.g. an abdominal abscess
pigtail catheter: used to drain air from around the lung (pneumothorax)
administration of intravenous fluids, medication or parenteral nutrition with a peripheral venous catheter or central venous catheter
angioplasty, angiography, balloon septostomy, balloon sinuplasty, cardiac electrophysiology testing, catheter ablation. Often the Seldinger technique is used. direct measurement of blood pressure in an artery or vein
direct measurement of intracranial pressure
administration of anaesthetic medication into the epidural space, the subarachnoid space, or around a major nerve bundle such as the brachial plexus
transfer of fertilized embryos, from in vitro fertilization, or sperm, during artificial insemination, into the uterus
administration of oxygen, volatile anesthetic agents, and other breathing gases into the lungs using a tracheal tube
subcutaneous administration of insulin or other medications, with the use of an infusion set and insulin pump

History
Ancient inventors
Ancient Chinese used onion stalks, the Romans, Hindus, and Greeks used tubes of wood or precious metals.The ancient Syrians created catheters from reeds. Modern
The earliest invention of the flexible catheter was during the 18th century.