Hemostasis in Obstetrics and Gynecology

What Is Hemostasis in Obstetrics and Gynecology?

• Hemostasis is a complex process that involves multiple interlinked steps culminating in the formation of a clot (or plug) that will close up the detached (or damaged in case of an injury) blood vessel, thereby controlling bleeding.

• Bleeding (or hemorrhage) during menstruation and parturition (the process of giving birth) is a normal biological process due to the contraction and shedding of the uterine lining and expulsion of the placenta.

• In the absence of underlying medical conditions, the average amount of blood loss after the birth of a single baby is about 500 ml, and it is around 30 ml to 40 ml during menstruation.

• The bleeding blood vessels that are attached to the uterus and the placenta need to be compressed through a process called hemostasis to prevent further bleeding.

• In a few complicated cases like obstetrical hemorrhage (excessive bleeding during birth) or menorrhagia (heavy menstrual bleeding), the normal physiological process of hemostasis will not be sufficient to control the bleeding.

• If left untreated, this can lead to life-threatening complications.

• Treatment involves a wide variety of hemostatic options like surgery, laser, hemostatic agents, etc. Early recognition and a multidisciplinary approach in management are the cornerstones of improving the outcome of such cases.

What Causes Hemorrhage in Obstetrics and Gynecology?

Bleeding during pregnancy and menstruation is normal and is caused due to hormonal changes, changes in the cervix, implantation, etc. These resolve on their own and do not need medical intervention; however, a few medical conditions that can cause excessive bleeding (Hemorrhage) are-

1. Pregnancy- Bleeding can happen during any of the three trimesters; some of the frequently seen causes are ectopic pregnancy (abnormal implantation of the fertilized egg), miscarriage (loss of pregnancy), molar pregnancy (an abnormally fertilized egg that eventually transforms into a mass of tissue), cervical infection, cervical growths, placental absorption, etc.

2. Parturition- Also known as labor, is a physiological process that involves various changes in the body of the pregnant mother leading to the expulsion of the fetus and the placenta. Parturition happens in stages and can be divided into antepartum, delivery, and postpartum. Any bleeding abnormalities during these three phases can lead to a life-threatening condition known as major obstructive hemorrhage (MOH). Different conditions that have been known to cause MOH are placenta previa (partial or complete coverage of the uterus with placenta), coagulopathies (bleeding disorders), uterine rupture, uterine atony (inadequate contractions), placenta accreta (abnormal growth of placenta into the uterine wall), carcinoma, etc.

3. Menstruation- In a few individuals, menstrual bleeding lasts for more than seven days leading to a condition called menorrhagia. Various conditions that can cause menorrhagia are hormonal imbalance, dysfunction of the ovaries, adenomyosis (abnormal growth of the endometrium into the walls of the uterus), intrauterine device (IUD), etc.

All of the conditions mentioned above will cause complications ranging from vaginal bleeding, pain, dizziness, anemia, hemorrhagic shock, and occasionally death. Apart from menorrhea, all of the conditions should be addressed immediately through hemostasis to avoid complications.

How Is Hemostasis Achieved in Obstetrics and Gynecology?

Treatment depends on the type of the condition, for example-

1. In individuals with MOH, treatment involves two components-

• Initial resuscitation and management of hemorrhagic/hypovolemic shock.

• Identification and management of the underlying condition.

Hemorrhagic shock refers to decreased tissue perfusion, leading to insufficient nutrient and oxygen delivery required for the normal functioning of cells due to hypovolemia secondary to massive hemorrhage. It should be managed by replacing the lost blood and fluids with intravenous fluids, blood, and blood products.

Surgery is the next possible option if the conventional methods are ineffective. The commonly performed surgical interventions are manual removal of the placenta, uterine packing, intrauterine balloon tamponade, uterine compression sutures, pelvic vessel ligations, uterine and hypogastric ligation, interventional radiology, and hysterectomy.

If the hemorrhage is caused due to menorrhagia, the first-like of treatment will be

Medical management of the condition with drugs like non-steroidal anti-inflammatory drugs, Tranexamic acid, oral contraceptives, and oral progesterone.

If the medication is ineffective, the next option is surgery. Various surgeries that are performed in individuals suffering from menorrhagia are dilation and curettage, uterine artery embolization, focussed ultrasound surgery, myomectomy, endometrial ablation, endometrial resection, and hysterectomy.

What Are Hemostatic Agents?

These are substances that are used as an adjunct to provide active and passive hemostasis in situations where bleeding is difficult or impractical to be controlled by conventional methods. There are four sub-categories of hemostatic agents that can be utilized for this purpose; they are-

1. Mechanical Hemostatic Agents- Mechanical hemostatic agents act as a scaffold for platelet aggregation and can dehydrate the injury bed allowing for a local increase in clotting factors.

This type of hemostatic agent, when used alone, acts passively to control hemostasis, which means that an intact clotting cascade is necessary for adequate clot stabilization. The commonly used mechanical hemostatic agents are-

• Oxidized regenerated cellulose ( trade name- Surgicel, Surgicel Fibrillar, Nu-Kit).
• Gelatins (Gelfoam, Surgifoam).
• Microfibrillar collagen (Trade name- Avitene, Avitene Ultrafoam, Avitene Ultrawrap)

2. Biological Hemostatic Agents- These are active ingredients that work to provide hemostasis by activating clotting factors in the final stages of the clotting cascade. The commonly used biological hemostatic agent is thrombin; the various types of thrombin are bovine thrombi (Thrombin-jmi), pooled human thrombin (Evithrom), and recombinant thrombin (Recothrom).

3. Flowable Hemostatic Agents- The most commonly used flowable hemostatic agents are Floseal and Gelfoam; however,, they are rarely used in obstetrics and gynecology due to their ability to contribute to adhesive diseases and their association with small bowel obstruction.

4. Fibrin Sealant- The commonly used fibrin sealants are pooled human plasma (Tisseel and Evicel), pooled human and equine collagen (Tachosil), and individual human plasma with bovine collagen and thrombin (Vitagel). Fibrin sealants are effective and are best used for bleeding from large surfaces.

In obstetrics, hemostatic agents are most often used to control postpartum hemorrhage in the setting of postpartum hemorrhage. They are far more commonly used in gynecological surgeries like hysterotomy, myomectomy, endometrial resection/ablation, etc.

Conclusion:

Hemostasis is a time-sensitive procedure that should be performed immediately after observing the associated clinical manifestations, especially during labor and the postpartum period. Immediate diagnosis and treatment can reduce the rate of maternal morbidity and mortality and improve the outcome.