As more blood is lost, the patient may feel cold, blood pressure may drop, and they may become unconscious.Signs and symptoms of circulatory shock may also include blurry vision, cold and clammy skin, confusion, and feeling sleepy or weak. Causes
Causes of postpartum hemorrhage are uterine atony, trauma, retained placenta or placental abnormalities, and coagulopathy, commonly referred to as the "four Ts":
Tone: uterine atony is the inability of the uterus to contract and may lead to continuous bleeding. Retained placental tissue and infection may contribute to uterine atony. Uterine atony is the most common cause of postpartum hemorrhage. Trauma: Injury to the birth canal which includes the uterus, cervix, vagina and the perineum which can happen even if the delivery is monitored properly. The bleeding is substantial as all these organs become more vascular during pregnancy. Tissue: retention of tissue from the placenta or fetus as well as placental abnormalities such as placenta accreta and percreta may lead to bleeding. Thrombin: a bleeding disorder occurs when there is a failure of clotting, such as with diseases known as coagulopathies.Other risk factors include obesity, fever during pregnancy, bleeding before delivery, and heart disease. Prevention
Oxytocin is typically used right after the delivery of the baby to prevent PPH. Misoprostol may be used in areas where oxytocin is not available.
In the active management group more patients returned to hospital with bleeding after discharge, and there was also a reduction in birthweight due to infants having a lower blood volume. The effects on the baby of early cord clamping was discussed in another review which found that delayed cord clamping improved iron stores longer term in the infants. Although they were more likely to need phototherapy (light therapy) to treat jaundice, the improved iron stores are expected to be worth increasing the practice of delayed cord clamping in healthy term babies.For preterm babies (babies born before 37 weeks) a review of the research found that delaying cord clamping may lead to fewer babies with bleeding in the brain, compared to early cord clamping.Another Cochrane review looking at the timing of the giving oxytocin as part of the active management found similar benefits with giving it before or after the expulsion of the placenta.There is no good quality evidence on how best to treat a secondary PPH (PPH occurring 24 hrs or more after the birth). Epidemiology
Methods of measuring blood loss associated with childbirth vary, complicating comparison of prevalence rates. A systematic review reported the highest rates of PPH in Africa (27.5%), and the lowest in Oceania (7.2%), with an overall rate globally of 10.8%. The rate in both Europe and North America was around 13%. The rate is higher for multiple pregnancies (32.4% compared with 10.6% for singletons), and for first-time mothers (12.9% compared with 10.0% for women in subsequent pregnancies).