Postpartum Hemorrhage: What You Need to Know

Postpartum hemorrhage is bleeding that occurs after childbirth. It is one of the most common obstetric emergencies, it’s the most common scenario of significant obstetric hemorrhage (bleeding related to pregnancy), and is a potential cause of maternal. death. It can be caused by uterine atony (failure of the uterus to contract after delivery), which is the most common cause. Other causes include trauma, such as a perineal tear or laceration (tear or cut of muscle between the vagina and anus), retained fragments of the placenta.

Factors that can put you at risk for postpartum hemorrhage include prolonged labor, instrumental delivery, uterine dysfunction, multiple gestation, previous postpartum hemorrhage, obesity, a large baby, failure to progress in the second stage of labor, general anesthesia, a prolonged third stage of labor (stage in which the placenta is delivered), preeclampsia, placenta accreta, and an episiotomy.

Preeclampsia is a condition characterized by elevated blood pressure developing in a pregnant woman beyond the 20th gestational week, the halfway point of pregnancy. Along with high blood pressure, preeclampsia includes dysfunction of an organ, usually the kidneys, so the urine must be tested, plus there are various blood tests. Preeclampsia endangers both the mother and the fetus, and the only cure is to deliver the fetus as soon as possible. Factors that put you at risk of developing preeclampsia include having a previous case of preeclampsia, having a relative who suffered preeclampsia, carrying a male fetus if you are not Asian, carrying a fetus with a genetic mutation called sFlt-1, having type 2 diabetes, being obese, being in your first pregnancy, and certain health problems.

Placenta accreta is a condition in which the placenta is attached too deeply into the uterus and consequently can become difficult to separate from the uterine wall after delivery. Normally, the placenta is attached only through the endometrium, the innermost layer of uterus. In placenta accreta, however, the placenta reaches through the endometrium and is up against the myometrium (the muscular layer of the uterus) or penetrates the myometrium. The condition is subcategorized based on how deep the penetration goes. During and following delivery of the baby, placenta accreta can cause severe bleeding, while also elevating the risk of uterine rupture. This is because, when the placenta does finally separate from the placenta, it can take parts of the myometrium with it.

Symptoms of postpartum hemorrhage may include heavy bleeding, abdominal pain, and abnormal uterine contractions.

Doctors will classify a mother as suffering from postpartum hemorrhage, if she suffers a loss of blood of at least 500 milliliters following a vaginal delivery, or at least 1,000 milliliters after a cesarean section (C-section). There are different ways to classify postpartum hemorrhage. One way is to divide it into minor or major postpartum hemorrhage. Minor postpartum hemorrhage is defined as being less than 1,000 milliliters blood loss, and major postpartum hemorrhage means 1,000 milliliters or more of blood loss. Major postpartum hemorrhage can be divided further into moderate postpartum hemorrhage if blood loss is 1,000-2,000 milliliters and severe postpartum hemorrhage, if more than 2,000 milliliters. A different way classify postpartum hemorrhage is primary postpartum hemorrhage (bleeding is within 24 hours of delivery) versus secondary postpartum hemorrhage (bleeding occurs anywhere from 24 hours to 12 weeks after delivery).

Various measures and precautions can help to prevent postpartum hemorrhage. One important measure is to recognize and treat gestational anemia during the antenatal period. Anemia is common during pregnancy, because the volume of blood within your body increases by up to 50 percent by the end of pregnancy. This causes decreasing concentration in red blood cells (RBCs), causing a drop in the RBC count when your blood is tested, along with a drop in hemoglobin, which in many cases is accompanied by changes in various measurements in the blood that doctors use to determine if you are iron deficient. The body begins compensating for the dilution of RBCs and hemoglobin by increasing RBC production. In some women, this acceleration in RBC production returns the RBC count and hemoglobin to normal, or close to normal by delivery, but often both the RBC count and hemoglobin remain low.

Another preventive measure is to give birth with an empty bladder since a full bladder reduces contractions of the uterus. Additionally, active management of the third stage of labor by giving oxytocin (intramuscular) to the mother makes postpartum hemorrhage less likely. As for women undergoing C-section, doctors can give medicines called an anti-fibrinolytic agent intravenously, the most common one being tranexamic acid.

It is important for doctors to diagnose and treat postpartum hemorrhage quickly, to prevent complications such as anemia, shock, and death. Postpartum hemorrhage is an emergency that must be addressed immediately by the medical team, consisting of various providers, from obstetricians and nurses (and sometimes midwives) to anesthesiologists, hematologists, and blood banking specialists. Treatment can include various medications, fluids, blood products, and surgical interventions.

David Warmflash
Dr. David Warmflash is a science communicator and physician with a research background in astrobiology and space medicine. He has completed research fellowships at NASA Johnson Space Center, the University of Pennsylvania, and Brandeis University. Since 2002, he has been collaborating with The Planetary Society on experiments helping us to understand the effects of deep space radiation on life forms, and since 2011 has worked nearly full time in medical writing and science journalism. His focus area includes the emergence of new biotechnologies and their impact on biomedicine, public health, and society.

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