At least three painful regular uterine contractions during a 10-minute period, each lasting more than 45 seconds.Many women are known to experience what has been termed the "nesting instinct". Women report a spurt of energy shortly before going into labour. Common signs that labour is about to begin may include what is known as lightening, which is the process of the baby moving down from the rib cage with the head of the baby engaging deep in the pelvis. The pregnant woman may then find breathing easier, since her lungs have more room for expansion, but pressure on her bladder may cause more frequent need to void (urinate). Lightening may occur a few weeks or a few hours before labour begins, or even not until labour has begun. Some women also experience an increase in vaginal discharge several days before labour begins when the "mucus plug", a thick plug of mucus that blocks the opening to the uterus, is pushed out into the vagina. The mucus plug may become dislodged days before labour begins or not until the start of labour.While inside the uterus the baby is enclosed in a fluid-filled membrane called the amniotic sac. Shortly before, at the beginning of, or during labour the sac ruptures.
Paracentesis (from Greek κεντάω, "to pierce") is a form of body fluid sampling procedure, generally referring to peritoneocentesis (also called laparocentesis or abdominal paracentesis) in which the peritoneal cavity is punctured by a needle to sample peritoneal fluid.The procedure is used to remove fluid from the peritoneal cavity, particularly if this cannot be achieved with medication. The most common indication is ascites that has developed in people with cirrhosis. Indications
It is used for a number of reasons:
to relieve abdominal pressure from ascites
to diagnose spontaneous bacterial peritonitis and other infections (e.g. abdominal TB)
to diagnose metastatic cancer
to diagnose blood in peritoneal space in trauma

For ascites
The procedure is often performed in a doctors office or an outpatient clinic. In an experts hands, it is usually very safe, although there is a small risk of infection, excessive bleeding or perforating a loop of bowel. These last two risks can be minimized greatly with the use of ultrasound guidance.The patient is requested to urinate before the procedure; alternately, a Foley catheter is used to empty the bladder. The patient is positioned in the bed with the head elevated at 45–60 degrees to allow fluid to accumulate in lower abdomen. After cleaning the side of the abdomen with an antiseptic solution, the physician numbs a small area of skin and inserts a large-bore needle with a plastic sheath 2 to 5 cm (1 to 2 in) in length to reach the peritoneal (ascitic) fluid. The needle is removed, leaving the plastic sheath to allow drainage of the fluid.