Complications during Childbirth

Episiotomy and Laceration Repairs

Perineal anatomy

The perineum Perineum The body region lying between the genital area and the anus on the surface of the trunk, and to the shallow compartment lying deep to this area that is inferior to the pelvic diaphragm. The surface area is between the vulva and the anus in the female, and between the scrotum and the anus in the male. Vagina, Vulva, and Pelvic Floor: Anatomy is the space between the vaginal and anal orifices.

• Perineal muscles:
  • Superficial transverse perineal muscle
  • Bulbocavernosus muscle
• Anorectal sphincter complex:
  • The entire complex measures approximately 4 cm. 
  • External anal sphincter External anal sphincter Rectum and Anal Canal: Anatomy:
    • Thick, circular, striated muscle Striated muscle One of two types of muscle in the body, characterized by the array of bands observed under microscope. Striated muscles can be divided into two subtypes: the cardiac muscle and the skeletal muscle. Muscle Tissue: Histology surrounding the anal orifice
    • Responsible for solid, liquid, and gas continence at rest and during rectal distention
    • Under voluntary control
  • Internal anal sphincter Internal anal sphincter Rectum and Anal Canal: Anatomy:
    • Thin condensation of the smooth muscle of the distal colon Colon The large intestines constitute the last portion of the digestive system. The large intestine consists of the cecum, appendix, colon (with ascending, transverse, descending, and sigmoid segments), rectum, and anal canal. The primary function of the colon is to remove water and compact the stool prior to expulsion from the body via the rectum and anal canal. Colon, Cecum, and Appendix: Anatomy submucosa
    • Responsible for continence at rest

Lacerations

Lacerations are spontaneous tears that occur due to the trauma of the infant passing through the vaginal canal during delivery.

• Epidemiology:
  • Up to 80% of women will sustain some type of laceration Laceration Torn, ragged, mangled wounds. Blunt Chest Trauma at vaginal delivery.
  • Most are 1st- and 2nd-degree tears.
• Location:
  • Perineal (most common)
  • Periclitoral
  • Periurethral
  • Labial
• Classifications of perineal lacerations:
  • 1st-degree:
    • Tear extends to the vaginal epithelium Epithelium The epithelium is a complex of specialized cellular organizations arranged into sheets and lining cavities and covering the surfaces of the body. The cells exhibit polarity, having an apical and a basal pole. Structures important for the epithelial integrity and function involve the basement membrane, the semipermeable sheet on which the cells rest, and interdigitations, as well as cellular junctions. Surface Epithelium: Histology and vulva Vulva The vulva is the external genitalia of the female and includes the mons pubis, labia majora, labia minora, clitoris, vestibule, vestibular bulb, and greater vestibular glands. Vagina, Vulva, and Pelvic Floor: Anatomy skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions only.
    • No perineal muscle injury 
  • 2nd-degree:
    • Tear extends to the perineal muscles.
    • No injury to the anal sphincter
  • 3rd-degree:
    • Tear extends through the perineal muscles and
    • Injury to the external anal sphincter External anal sphincter Rectum and Anal Canal: Anatomy
  • 4th-degree:
    • Tear extends through the entire external anal sphincter External anal sphincter Rectum and Anal Canal: Anatomy and into rectal mucosa.
    • Most severe form
• Risk factors for anal sphincter injury:
  • Operative vaginal delivery
  • Midline episiotomy
  • Macrosomia
  • Primiparity (1st delivery)
• Prevention of anal sphincter injury:
  • Perineal massage antenatally and intrapartum
  • Manual perineal support at delivery (poor-quality data, but commonly done)
  • Warm compresses Warm Compresses Chalazion
• Treatment:
  • Adequate analgesia Analgesia Methods of pain relief that may be used with or in place of analgesics. Anesthesiology: History and Basic Concepts  
  • Surgical repair (suturing) in layers
  • Single dose of antibiotics for the 3rd- and 4th-degree lacerations 
• Complications of 3rd- and 4th-degree lacerations:
  • Wound breakdown
  • Fecal incontinence Fecal incontinence Failure of voluntary control of the anal sphincters, with involuntary passage of feces and flatus. Pediatric Constipation
  • Pelvic organ prolapse Pelvic Organ Prolapse Pelvic organ prolapse (POP) is a general term that refers to herniation of 1 or more pelvic organs (e.g., bladder, uterus, rectum) into the vaginal canal, and potentially all the way through the introitus. Weakness and insufficiency of the pelvic floor may result in POP. Pelvic Organ Prolapse
  • Rectovaginal fistulas 
  • Pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways, including dyspareunia Dyspareunia Recurrent genital pain occurring during, before, or after sexual intercourse in either the male or the female. Primary Ovarian Insufficiency

Episiotomy

An episiotomy is an intentional 3–5-cm incision made by the delivering provider to enlarge the vaginal opening at the time of delivery.

• Not recommended for routine deliveries
• Indications:
  • Woman at high risk for a 3rd- or 4th-degree laceration Laceration Torn, ragged, mangled wounds. Blunt Chest Trauma.
  • Nonreassuring fetal heart rate Heart rate The number of times the heart ventricles contract per unit of time, usually per minute. Cardiac Physiology tracing that warrants hastening vaginal delivery
  • Create space for the provider to:
    • Perform internal maneuvers to relieve a shoulder dystocia
    • Safely apply forceps Forceps Surgical Instruments and Sutures or a vacuum for an operative vaginal delivery
• Types/location:
  • Mediolateral
    • Incision is cut at an angle toward the ischial tuberosity Ischial Tuberosity Chronic Apophyseal Injury (about 45 degrees from midline).
    • Preferred because ↓ risk of extension Extension Examination of the Upper Limbs into the anal sphincter
  • Midline
• Episiotomy ↑ risk of:
  • Extension Extension Examination of the Upper Limbs to 3rd- and 4th-degree lacerations (especially with midline incisions)
  • 3rd- or 4th-degree lacerations in subsequent deliveries
  • Greater blood loss
  • Infection and dehiscence
  • Dyspareunia Dyspareunia Recurrent genital pain occurring during, before, or after sexual intercourse in either the male or the female. Primary Ovarian Insufficiency at 1 year postpartum

Operative Vaginal Delivery

Overview

Operative vaginal delivery is the use of obstetric forceps Forceps Surgical Instruments and Sutures or a vacuum extractor to effect delivery of a fetus. 

• Epidemiology:
  • Overall incidence Incidence The number of new cases of a given disease during a given period in a specified population. It also is used for the rate at which new events occur in a defined population. It is differentiated from prevalence, which refers to all cases in the population at a given time. Measures of Disease Frequency: approximately 3% of deliveries
  • Forceps Forceps Surgical Instruments and Sutures: 0.5% of all vaginal births
  • Vacuum: 2.6% of all vaginal births
• Indications:
  • Fetal distress in the 2nd stage of labor 2nd stage of labor The period of obstetric labor that is from the complete dilatation of the cervix uteri to the expulsion of the fetus. Normal and Abnormal Labor (2nd stage: time from complete dilation through delivery of the fetus; “pushing”)
  • Prolonged or arrested 2nd stage of labor 2nd stage of labor The period of obstetric labor that is from the complete dilatation of the cervix uteri to the expulsion of the fetus. Normal and Abnormal Labor
  • Shortening of the 2nd stage of labor 2nd stage of labor The period of obstetric labor that is from the complete dilatation of the cervix uteri to the expulsion of the fetus. Normal and Abnormal Labor for maternal medical indications (conditions that prevent safe maternal pushing):
    • Maternal cardiac disease (e.g., heart failure Heart Failure A heterogeneous condition in which the heart is unable to pump out sufficient blood to meet the metabolic need of the body. Heart failure can be caused by structural defects, functional abnormalities (ventricular dysfunction), or a sudden overload beyond its capacity. Chronic heart failure is more common than acute heart failure which results from sudden insult to cardiac function, such as myocardial infarction. Total Anomalous Pulmonary Venous Return (TAPVR))
    • Maternal intracranial pathology (e.g., berry aneurysms Berry aneurysms Brain Aneurysms)
  • Maternal exhaustion
• Criteria required to perform operative vaginal deliveries:
  • Vertex presentation
  • Ruptured fetal membranes
  • Full cervical dilation Cervical dilation A measurement of the diameter of the cervical canal, reported in centimeters Normal and Abnormal Labor (10 cm)
  • At least +2 station (fetal head is 2 cm below the maternal ischial spine Spine The human spine, or vertebral column, is the most important anatomical and functional axis of the human body. It consists of 7 cervical vertebrae, 12 thoracic vertebrae, and 5 lumbar vertebrae and is limited cranially by the skull and caudally by the sacrum. Vertebral Column: Anatomy)
  • Knowledge of the fetal position Fetal position Direction of the fetal head in relation to the maternal pelvis in vertex presentations Normal and Abnormal Labor (e.g., occiput anterior versus posterior)
  • Adequate anesthesia Anesthesia A state characterized by loss of feeling or sensation. This depression of nerve function is usually the result of pharmacologic action and is induced to allow performance of surgery or other painful procedures. Anesthesiology: History and Basic Concepts
  • Empty maternal bladder Bladder A musculomembranous sac along the urinary tract. Urine flows from the kidneys into the bladder via the ureters, and is held there until urination. Pyelonephritis and Perinephric Abscess

Vacuum-assisted delivery

• Technique:
  • A vacuum extractor is applied to the fetal vertex.
    • Centered over the sagittal suture Sagittal suture Cranial suture, or a type of fibrous joint, between the parietal bones, along the midline. Skull: Anatomy
    • Avoid placement over the fontanelles Fontanelles Physical Examination of the Newborn.
  • Steady downward traction is applied during contractions with maternal pushing.
• Maternal complications
  • 2-fold ↑ risk of 3rd- and 4th-degree perineal lacerations (involves the anal sphincter)
  • Vulvar and vaginal hematomas
  • Urinary tract Urinary tract The urinary tract is located in the abdomen and pelvis and consists of the kidneys, ureters, urinary bladder, and urethra. The structures permit the excretion of urine from the body. Urine flows from the kidneys through the ureters to the urinary bladder and out through the urethra. Urinary Tract: Anatomy injury
  • Lower rates of maternal complications with vacuum as compared with forceps Forceps Surgical Instruments and Sutures and cesarean deliveries
• Fetal complications:
  • Fetal scalp lacerations
  • Cephalohematoma Cephalohematoma Von Willebrand Disease → hyperbilirubinemia Hyperbilirubinemia A condition characterized by an abnormal increase of bilirubin in the blood, which may result in jaundice. Bilirubin, a breakdown product of heme, is normally excreted in the bile or further catabolized before excretion in the urine. Jaundice
  • Intracranial hemorrhage Intracranial hemorrhage Subarachnoid hemorrhage (SAH) is a type of cerebrovascular accident (stroke) resulting from intracranial hemorrhage into the subarachnoid space between the arachnoid and the pia mater layers of the meninges surrounding the brain. Most sahs originate from a saccular aneurysm in the circle of willis but may also occur as a result of trauma, uncontrolled hypertension, vasculitis, anticoagulant use, or stimulant use. Subarachnoid Hemorrhage

Forceps-assisted delivery

• Technique:
  • Obstetric forceps Forceps Surgical Instruments and Sutures are applied around the fetal head.
  • Steady downward traction is applied during contractions with maternal pushing.
• Maternal complications:
  • 6-fold ↑ risk of 3rd- and 4th-degree perineal lacerations 
  • Vulvar and vaginal hematomas
  • Urinary tract Urinary tract The urinary tract is located in the abdomen and pelvis and consists of the kidneys, ureters, urinary bladder, and urethra. The structures permit the excretion of urine from the body. Urine flows from the kidneys through the ureters to the urinary bladder and out through the urethra. Urinary Tract: Anatomy injury
• Fetal complications:
  • Facial lacerations
  • Facial nerve Facial nerve The 7th cranial nerve. The facial nerve has two parts, the larger motor root which may be called the facial nerve proper, and the smaller intermediate or sensory root. Together they provide efferent innervation to the muscles of facial expression and to the lacrimal and salivary glands, and convey afferent information for taste from the anterior two-thirds of the tongue and for touch from the external ear. The 12 Cranial Nerves: Overview and Functions injury
  • Skull Skull The skull (cranium) is the skeletal structure of the head supporting the face and forming a protective cavity for the brain. The skull consists of 22 bones divided into the viscerocranium (facial skeleton) and the neurocranium. Skull: Anatomy fracture Fracture A fracture is a disruption of the cortex of any bone and periosteum and is commonly due to mechanical stress after an injury or accident. Open fractures due to trauma can be a medical emergency. Fractures are frequently associated with automobile accidents, workplace injuries, and trauma. Overview of Bone Fractures
  • Intracranial hemorrhage Intracranial hemorrhage Subarachnoid hemorrhage (SAH) is a type of cerebrovascular accident (stroke) resulting from intracranial hemorrhage into the subarachnoid space between the arachnoid and the pia mater layers of the meninges surrounding the brain. Most sahs originate from a saccular aneurysm in the circle of willis but may also occur as a result of trauma, uncontrolled hypertension, vasculitis, anticoagulant use, or stimulant use. Subarachnoid Hemorrhage

Shoulder Dystocia

Overview

Shoulder dystocia is when the baby’s anterior shoulder becomes impacted behind the maternal pubic symphysis Pubic Symphysis A slightly movable cartilaginous joint which occurs between the pubic bones. Vagina, Vulva, and Pelvic Floor: Anatomy, preventing delivery of the fetal body. Shoulder dystocia is a true obstetric emergency.

• Definition:
  • Failure to deliver the fetal shoulders with gentle downward traction, where additional maneuvers are required to deliver the baby 
  • This is a bone-on-bone obstruction → episiotomy will not relieve shoulder dystocia
  • During the dystocia, the fetus is not getting any oxygen. 
• Epidemiology:
  • Incidence Incidence The number of new cases of a given disease during a given period in a specified population. It also is used for the rate at which new events occur in a defined population. It is differentiated from prevalence, which refers to all cases in the population at a given time. Measures of Disease Frequency: 0.2%–3% of vaginal births in the vertex presentation
  • Risk of recurrence: 10%–16% 
  • Unpredictable and can occur in any laboring woman
• Risk factors (though shoulder dystocia often occurs in the absence of risk factors):
  • Fetal macrosomia Fetal macrosomia A condition of fetal overgrowth leading to a large-for-gestational-age fetus. It is defined as birth weight greater than 4, 000 grams or above the 90th percentile for population and sex-specific growth curves. It is commonly seen in gestational diabetes; prolonged pregnancy; and pregnancies complicated by pre-existing diabetes mellitus. Wilms Tumor
  • Maternal diabetes mellitus Diabetes mellitus Diabetes mellitus (DM) is a metabolic disease characterized by hyperglycemia and dysfunction of the regulation of glucose metabolism by insulin. Type 1 DM is diagnosed mostly in children and young adults as the result of autoimmune destruction of β cells in the pancreas and the resulting lack of insulin. Type 2 DM has a significant association with obesity and is characterized by insulin resistance. Diabetes Mellitus (pregestational or gestational)
  • Previous shoulder dystocia
  • Maternal obesity Obesity Obesity is a condition associated with excess body weight, specifically with the deposition of excessive adipose tissue. Obesity is considered a global epidemic. Major influences come from the western diet and sedentary lifestyles, but the exact mechanisms likely include a mixture of genetic and environmental factors. Obesity 
  • Operative vaginal delivery 
  • Prolonged 2nd stage of labor 2nd stage of labor The period of obstetric labor that is from the complete dilatation of the cervix uteri to the expulsion of the fetus. Normal and Abnormal Labor
• Clinical presentation:
  • Failure of the fetal shoulders to deliver with gentle downward traction on the fetal head
  • Turtle sign: retraction of the fetal head tightly against the maternal perineum Perineum The body region lying between the genital area and the anus on the surface of the trunk, and to the shallow compartment lying deep to this area that is inferior to the pelvic diaphragm. The surface area is between the vulva and the anus in the female, and between the scrotum and the anus in the male. Vagina, Vulva, and Pelvic Floor: Anatomy
  • Abnormal progression of the 2nd stage of labor 2nd stage of labor The period of obstetric labor that is from the complete dilatation of the cervix uteri to the expulsion of the fetus. Normal and Abnormal Labor

Initial management

Shoulder dystocia is an obstetric emergency. 

• Call for help.
• Have mother stop pushing.
  • Pushing is only further forcing the shoulder into the pubic symphysis Pubic Symphysis A slightly movable cartilaginous joint which occurs between the pubic bones. Vagina, Vulva, and Pelvic Floor: Anatomy.
  • Relaxing allows room for maneuvers to dislodge the shoulder.
• Immediately have mother assume the McRoberts position:
  • Abduction Abduction Examination of the Upper Limbs + hyperflexion of the maternal hips
  • “Knees to armpits”
  • Causes cephalad rotation Rotation Motion of an object in which either one or more points on a line are fixed. It is also the motion of a particle about a fixed point. X-rays of the pubic symphysis Pubic Symphysis A slightly movable cartilaginous joint which occurs between the pubic bones. Vagina, Vulva, and Pelvic Floor: Anatomy and flattens the lumbar lordosis → maximizes the pelvic diameter
• Suprapubic pressure:
  • Attempts to push the shoulder down and inward 
  • Slightly rotates the fetus and dislodges the impacted shoulder
  • Avoid fundal pressure, which may make the dystocia worse.
• Manual delivery of the posterior arm Arm The arm, or “upper arm” in common usage, is the region of the upper limb that extends from the shoulder to the elbow joint and connects inferiorly to the forearm through the cubital fossa. It is divided into 2 fascial compartments (anterior and posterior). Arm: Anatomy
  • Reduces the bisacromial diameter
  • ↑ Risk of clavicular and/or humerus Humerus Bone in humans and primates extending from the shoulder joint to the elbow joint. Arm: Anatomy fracture Fracture A fracture is a disruption of the cortex of any bone and periosteum and is commonly due to mechanical stress after an injury or accident. Open fractures due to trauma can be a medical emergency. Fractures are frequently associated with automobile accidents, workplace injuries, and trauma. Overview of Bone Fractures
• 95% of shoulder dystocias will be relieved with the management described.

Additional maneuvers

Additional maneuvers to attempt if the dystocia persists include:

• Rotational maneuvers:
  • Attempt to manually rotate the shoulders
  • Rubin’s maneuver: rotate the anterior or posterior fetal shoulder anteriorly toward the fetal face
  • Woods screw maneuver: rotate the posterior fetal shoulder backward
• Gaskin maneuver:
  • Have mother assume a position on her hands and knees.
  • Repeat above maneuvers in this position.
  • May be helpful in women who are not anesthetized
• Intentional clavicular fracture Fracture A fracture is a disruption of the cortex of any bone and periosteum and is commonly due to mechanical stress after an injury or accident. Open fractures due to trauma can be a medical emergency. Fractures are frequently associated with automobile accidents, workplace injuries, and trauma. Overview of Bone Fractures:
  • Pop the anterior clavicle Clavicle A bone on the ventral side of the shoulder girdle, which in humans is commonly called the collar bone. Clavicle Fracture outward to ↓ the bisacromial diameter.
  • ↑ Risk of injury to vasculature and pulmonary structures
  • Less morbidity Morbidity The proportion of patients with a particular disease during a given year per given unit of population. Measures of Health Status than procedures of last resort
• Episiotomy:
  • Episiotomy will not relieve shoulder dystocia.
  • Consider cutting one to allow space to adequately perform the maneuvers.
• Repeat all above maneuvers several times before moving on to procedures of last resort.
• Procedures of last resort:
  • Zavanelli maneuver:
    • Replace the fetal head in the abdomen by reversing the cardinal movements of labor and perform an urgent cesarean delivery Cesarean Delivery Cesarean delivery (CD) is the operative delivery of ≥ 1 infants through a surgical incision in the maternal abdomen and uterus. Cesarean deliveries may be indicated for a number of either maternal or fetal reasons, most commonly including fetal intolerance to labor, arrest of labor, a history of prior uterine surgery, fetal malpresentation, and placental abnormalities. Cesarean Delivery.
    • High morbidity Morbidity The proportion of patients with a particular disease during a given year per given unit of population. Measures of Health Status and mortality Mortality All deaths reported in a given population. Measures of Health Status
  • Abdominal rescue:
    • Make a hysterotomy, manually reduce the impacted shoulder, and deliver vaginally.
    • Done when the head is unable to be manually replaced during attempted Zavanelli maneuver
  • Symphysiotomy:
    • Surgical division of the cartilage Cartilage Cartilage is a type of connective tissue derived from embryonic mesenchyme that is responsible for structural support, resilience, and the smoothness of physical actions. Perichondrium (connective tissue membrane surrounding cartilage) compensates for the absence of vasculature in cartilage by providing nutrition and support. Cartilage: Histology of the pubic symphysis Pubic Symphysis A slightly movable cartilaginous joint which occurs between the pubic bones. Vagina, Vulva, and Pelvic Floor: Anatomy
    • Only used when an OR is unavailable

To remember the management of a shoulder dystocia, remember HELPERR:

• Call for Help.
• Consider an Episiotomy (to allow space for maneuvers).
• Elevate the Legs.
• Apply suprapubic Pressure.
• Enter the vagina Vagina The vagina is the female genital canal, extending from the vulva externally to the cervix uteri internally. The structures have sexual, reproductive, and urinary functions and a rich blood supply, mainly arising from the internal iliac artery. Vagina, Vulva, and Pelvic Floor: Anatomy for internal rotational maneuvers.
• Reliever the posterior arm Arm The arm, or “upper arm” in common usage, is the region of the upper limb that extends from the shoulder to the elbow joint and connects inferiorly to the forearm through the cubital fossa. It is divided into 2 fascial compartments (anterior and posterior). Arm: Anatomy.
• Rotate the woman to hands-and-knees position.

Complications

• Brachial plexus Brachial Plexus The large network of nerve fibers which distributes the innervation of the upper extremity. The brachial plexus extends from the neck into the axilla. In humans, the nerves of the plexus usually originate from the lower cervical and the first thoracic spinal cord segments (c5-c8 and T1), but variations are not uncommon. Peripheral Nerve Injuries in the Cervicothoracic Region injury
  • Erb palsy Erb Palsy Mononeuropathy and Plexopathy:
    • Stretching of the C5 and C6 nerves from continuous downward traction on the head
    • Often reversible
    • 75% of brachial plexus Brachial Plexus The large network of nerve fibers which distributes the innervation of the upper extremity. The brachial plexus extends from the neck into the axilla. In humans, the nerves of the plexus usually originate from the lower cervical and the first thoracic spinal cord segments (c5-c8 and T1), but variations are not uncommon. Peripheral Nerve Injuries in the Cervicothoracic Region injury
  • Klumpke palsy Palsy paralysis of an area of the body, thus incapable of voluntary movement Cranial Nerve Palsies: stretching of C8 and T1 nerves
• Clavicular fracture Fracture A fracture is a disruption of the cortex of any bone and periosteum and is commonly due to mechanical stress after an injury or accident. Open fractures due to trauma can be a medical emergency. Fractures are frequently associated with automobile accidents, workplace injuries, and trauma. Overview of Bone Fractures
• Humerus Humerus Bone in humans and primates extending from the shoulder joint to the elbow joint. Arm: Anatomy fracture Fracture A fracture is a disruption of the cortex of any bone and periosteum and is commonly due to mechanical stress after an injury or accident. Open fractures due to trauma can be a medical emergency. Fractures are frequently associated with automobile accidents, workplace injuries, and trauma. Overview of Bone Fractures
• Fetal asphyxia Asphyxia A pathological condition caused by lack of oxygen, manifested in impending or actual cessation of life. Drowning
• Contusions and lacerations

Amniotic Fluid Embolism

Overview

Amniotic fluid Amniotic fluid A clear, yellowish liquid that envelopes the fetus inside the sac of amnion. In the first trimester, it is likely a transudate of maternal or fetal plasma. In the second trimester, amniotic fluid derives primarily from fetal lung and kidney. Cells or substances in this fluid can be removed for prenatal diagnostic tests (amniocentesis). Placenta, Umbilical Cord, and Amniotic Cavity embolism (AFE) is a complication of labor affecting the mother in the immediate postpartum period Postpartum period In females, the period that is shortly after giving birth (parturition). Postpartum Complications.

• Caused by entry of amniotic fluid Amniotic fluid A clear, yellowish liquid that envelopes the fetus inside the sac of amnion. In the first trimester, it is likely a transudate of maternal or fetal plasma. In the second trimester, amniotic fluid derives primarily from fetal lung and kidney. Cells or substances in this fluid can be removed for prenatal diagnostic tests (amniocentesis). Placenta, Umbilical Cord, and Amniotic Cavity into the maternal circulation Circulation The movement of the blood as it is pumped through the cardiovascular system. ABCDE Assessment by:
  • Placental tears
  • Uterine vein rupture
• Incidence Incidence The number of new cases of a given disease during a given period in a specified population. It also is used for the rate at which new events occur in a defined population. It is differentiated from prevalence, which refers to all cases in the population at a given time. Measures of Disease Frequency: 1 in 40,000 deliveries
• Mortality Mortality All deaths reported in a given population. Measures of Health Status:
  •  80% mortality rate Mortality rate Calculated as the ratio of the total number of people who die due to all causes over a specific time period to the total number of people in the selected population. Measures of Health Status 
  • AFE causes 10% of maternal deaths in developed countries.

Risk factors

• Cesarean delivery Cesarean Delivery Cesarean delivery (CD) is the operative delivery of ≥ 1 infants through a surgical incision in the maternal abdomen and uterus. Cesarean deliveries may be indicated for a number of either maternal or fetal reasons, most commonly including fetal intolerance to labor, arrest of labor, a history of prior uterine surgery, fetal malpresentation, and placental abnormalities. Cesarean Delivery
• Operative vaginal deliveries
• Placental abnormalities Placental abnormalities Normal placental structure and function are essential for a healthy pregnancy. Some of the most common placental abnormalities include structural anomalies (such as a succenturiate lobe or velamentous cord insertion), implantation anomalies (such as placenta accreta and placenta previa), and functional anomalies (such as placental insufficiency). Placental Abnormalities (e.g., placenta Placenta A highly vascularized mammalian fetal-maternal organ and major site of transport of oxygen, nutrients, and fetal waste products. It includes a fetal portion (chorionic villi) derived from trophoblasts and a maternal portion (decidua) derived from the uterine endometrium. The placenta produces an array of steroid, protein and peptide hormones (placental hormones). Placenta, Umbilical Cord, and Amniotic Cavity previa)
• Preeclampsia Preeclampsia A complication of pregnancy, characterized by a complex of symptoms including maternal hypertension and proteinuria with or without pathological edema. Symptoms may range between mild and severe. Pre-eclampsia usually occurs after the 20th week of gestation, but may develop before this time in the presence of trophoblastic disease. Hypertensive Pregnancy Disorders/ eclampsia Eclampsia Onset of hyperreflexia; seizures; or coma in a previously diagnosed pre-eclamptic patient (pre-eclampsia). Hypertensive Pregnancy Disorders

Pathogenesis

• Unclear
• Amniotic fluid Amniotic fluid A clear, yellowish liquid that envelopes the fetus inside the sac of amnion. In the first trimester, it is likely a transudate of maternal or fetal plasma. In the second trimester, amniotic fluid derives primarily from fetal lung and kidney. Cells or substances in this fluid can be removed for prenatal diagnostic tests (amniocentesis). Placenta, Umbilical Cord, and Amniotic Cavity enters maternal circulation Circulation The movement of the blood as it is pumped through the cardiovascular system. ABCDE Assessment and triggers:
  • Intense pulmonary vasoconstriction Vasoconstriction The physiological narrowing of blood vessels by contraction of the vascular smooth muscle. Vascular Resistance, Flow, and Mean Arterial Pressure:
    • ↑ Pulmonary pressure → right ventricular failure → systemic hypotension Hypotension Hypotension is defined as low blood pressure, specifically < 90/60 mm Hg, and is most commonly a physiologic response. Hypotension may be mild, serious, or life threatening, depending on the cause. Hypotension
    • Hypoxemic respiratory failure Respiratory failure Respiratory failure is a syndrome that develops when the respiratory system is unable to maintain oxygenation and/or ventilation. Respiratory failure may be acute or chronic and is classified as hypoxemic, hypercapnic, or a combination of the two. Respiratory Failure
    • Pulmonary edema Edema Edema is a condition in which excess serous fluid accumulates in the body cavity or interstitial space of connective tissues. Edema is a symptom observed in several medical conditions. It can be categorized into 2 types, namely, peripheral (in the extremities) and internal (in an organ or body cavity). Edema
  • An abnormal immune response:
    • Intense inflammatory response (similar to SIRS) is activated.
    • Inflammatory mediators activate the coagulation cascade Coagulation cascade The coagulation cascade is a series of reactions that ultimately generates a strong, cross-linked fibrin clot. Hemostasis systemically → DIC DIC Disseminated intravascular coagulation (DIC) is a condition characterized by systemic bodywide activation of the coagulation cascade. This cascade results in both widespread microvascular thrombi contributing to multiple organ dysfunction and consumption of clotting factors and platelets, leading to hemorrhage. Disseminated Intravascular Coagulation 
• DIC DIC Disseminated intravascular coagulation (DIC) is a condition characterized by systemic bodywide activation of the coagulation cascade. This cascade results in both widespread microvascular thrombi contributing to multiple organ dysfunction and consumption of clotting factors and platelets, leading to hemorrhage. Disseminated Intravascular Coagulation leads to:
  • Hemorrhage → further hemodynamic instability
  • Ischemic multiorgan failure
• Mechanical obstruction Mechanical Obstruction Any impairment, arrest, or reversal of the normal flow of intestinal contents toward the anal canal. Imaging of the Intestines from amniotic fluid Amniotic fluid A clear, yellowish liquid that envelopes the fetus inside the sac of amnion. In the first trimester, it is likely a transudate of maternal or fetal plasma. In the second trimester, amniotic fluid derives primarily from fetal lung and kidney. Cells or substances in this fluid can be removed for prenatal diagnostic tests (amniocentesis). Placenta, Umbilical Cord, and Amniotic Cavity debris likely does not play a significant role.

Clinical presentation

Amniotic fluid Amniotic fluid A clear, yellowish liquid that envelopes the fetus inside the sac of amnion. In the first trimester, it is likely a transudate of maternal or fetal plasma. In the second trimester, amniotic fluid derives primarily from fetal lung and kidney. Cells or substances in this fluid can be removed for prenatal diagnostic tests (amniocentesis). Placenta, Umbilical Cord, and Amniotic Cavity embolism typically presents dramatically, as sudden onset cardiopulmonary collapse occurring during labor or within 30 minutes after delivery.

• Signs:
  • Cardiopulmonary collapse: loss of breathing and pulse
  • Hypoxemia Hypoxemia Neonatal Respiratory Distress Syndrome/ cyanosis Cyanosis A bluish or purplish discoloration of the skin and mucous membranes due to an increase in the amount of deoxygenated hemoglobin in the blood or a structural defect in the hemoglobin molecule. Pulmonary Examination
  • Dyspnea Dyspnea Dyspnea is the subjective sensation of breathing discomfort. Dyspnea is a normal manifestation of heavy physical or psychological exertion, but also may be caused by underlying conditions (both pulmonary and extrapulmonary). Dyspnea
  • Hypotension Hypotension Hypotension is defined as low blood pressure, specifically < 90/60 mm Hg, and is most commonly a physiologic response. Hypotension may be mild, serious, or life threatening, depending on the cause. Hypotension
  • Tachycardia Tachycardia Abnormally rapid heartbeat, usually with a heart rate above 100 beats per minute for adults. Tachycardia accompanied by disturbance in the cardiac depolarization (cardiac arrhythmia) is called tachyarrhythmia. Sepsis in Children 
• Other symptoms:
  • Nausea Nausea An unpleasant sensation in the stomach usually accompanied by the urge to vomit. Common causes are early pregnancy, sea and motion sickness, emotional stress, intense pain, food poisoning, and various enteroviruses. Antiemetics and vomiting Vomiting The forcible expulsion of the contents of the stomach through the mouth. Hypokalemia
  • Mental status changes 
  • Seizure 
• DIC DIC Disseminated intravascular coagulation (DIC) is a condition characterized by systemic bodywide activation of the coagulation cascade. This cascade results in both widespread microvascular thrombi contributing to multiple organ dysfunction and consumption of clotting factors and platelets, leading to hemorrhage. Disseminated Intravascular Coagulation:
  • Usually develops shortly after an AFE
  • Leads to obstetric hemorrhage
  • Bleeding from catheter sites and mucosal surfaces
• Fetal heart rate Heart rate The number of times the heart ventricles contract per unit of time, usually per minute. Cardiac Physiology abnormalities indicating distress (e.g., late decelerations, terminal bradycardia Bradycardia Bradyarrhythmia is a rhythm in which the heart rate is less than 60/min. Bradyarrhythmia can be physiologic, without symptoms or hemodynamic change. Pathologic bradyarrhythmia results in reduced cardiac output and hemodynamic instability causing syncope, dizziness, or dyspnea. Bradyarrhythmias) if still pregnant

Diagnosis

Amniotic fluid Amniotic fluid A clear, yellowish liquid that envelopes the fetus inside the sac of amnion. In the first trimester, it is likely a transudate of maternal or fetal plasma. In the second trimester, amniotic fluid derives primarily from fetal lung and kidney. Cells or substances in this fluid can be removed for prenatal diagnostic tests (amniocentesis). Placenta, Umbilical Cord, and Amniotic Cavity embolism is a clinical diagnosis based on presentation. 

• Laboratory evaluation (primarily to help with resuscitation Resuscitation The restoration to life or consciousness of one apparently dead. . Neonatal Respiratory Distress Syndrome):
  • Coagulation profile:
    • ↑ Prothrombin Prothrombin A plasma protein that is the inactive precursor of thrombin. It is converted to thrombin by a prothrombin activator complex consisting of factor Xa, factor V, phospholipid, and calcium ions. Hemostasis time
    • ↓ Fibrinogen Fibrinogen Plasma glycoprotein clotted by thrombin, composed of a dimer of three non-identical pairs of polypeptide chains (alpha, beta, gamma) held together by disulfide bonds. Fibrinogen clotting is a sol-gel change involving complex molecular arrangements: whereas fibrinogen is cleaved by thrombin to form polypeptides a and b, the proteolytic action of other enzymes yields different fibrinogen degradation products. Hemostasis
    • ↑ D-dimer D-dimer Deep Vein Thrombosis
  • CBC:
    • Anemia Anemia Anemia is a condition in which individuals have low Hb levels, which can arise from various causes. Anemia is accompanied by a reduced number of RBCs and may manifest with fatigue, shortness of breath, pallor, and weakness. Subtypes are classified by the size of RBCs, chronicity, and etiology. Anemia: Overview and Types 
    • Leukocytosis Leukocytosis A transient increase in the number of leukocytes in a body fluid. West Nile Virus
    • Thrombocytopenia Thrombocytopenia Thrombocytopenia occurs when the platelet count is < 150,000 per microliter. The normal range for platelets is usually 150,000-450,000/µL of whole blood. Thrombocytopenia can be a result of decreased production, increased destruction, or splenic sequestration of platelets. Patients are often asymptomatic until platelet counts are < 50,000/µL. Thrombocytopenia 
  • Arterial blood gas Arterial blood gas Respiratory Alkalosis:
    • Hypoxemia Hypoxemia Neonatal Respiratory Distress Syndrome
    • Acidosis Acidosis A pathologic condition of acid accumulation or depletion of base in the body. The two main types are respiratory acidosis and metabolic acidosis, due to metabolic acid build up. Respiratory Acidosis (both respiratory and metabolic)
• Imaging (once woman is stable enough):
  • Chest radiography: bilateral diffuse infiltrates
  • Echocardiography Echocardiography Ultrasonic recording of the size, motion, and composition of the heart and surrounding tissues. The standard approach is transthoracic. Tricuspid Valve Atresia (TVA) to assess cardiac function, which may have become compromised

Management

Survival depends on prompt diagnosis and effective resuscitation Resuscitation The restoration to life or consciousness of one apparently dead. . Neonatal Respiratory Distress Syndrome.

• Airway Airway ABCDE Assessment: Secure the airway Airway ABCDE Assessment.
• Breathing: mechanical ventilation Ventilation The total volume of gas inspired or expired per unit of time, usually measured in liters per minute. Ventilation: Mechanics of Breathing
• Circulation Circulation The movement of the blood as it is pumped through the cardiovascular system. ABCDE Assessment:
  • High-quality cardiopulmonary resuscitation Resuscitation The restoration to life or consciousness of one apparently dead. . Neonatal Respiratory Distress Syndrome ( CPR CPR The artificial substitution of heart and lung action as indicated for heart arrest resulting from electric shock, drowning, respiratory arrest, or other causes. The two major components of cardiopulmonary resuscitation are artificial ventilation and closed-chest cardiac massage. Cardiac Arrest)
  • 2 large-bore IVs → fluid resuscitation Resuscitation The restoration to life or consciousness of one apparently dead. . Neonatal Respiratory Distress Syndrome
  • Transfuse to combat DIC DIC Disseminated intravascular coagulation (DIC) is a condition characterized by systemic bodywide activation of the coagulation cascade. This cascade results in both widespread microvascular thrombi contributing to multiple organ dysfunction and consumption of clotting factors and platelets, leading to hemorrhage. Disseminated Intravascular Coagulation; typically a 1:1:1 ratio of:
    • Packed RBCs Packed RBCs Transfusion Products
    • Fresh frozen plasma Plasma The residual portion of blood that is left after removal of blood cells by centrifugation without prior blood coagulation. Transfusion Products
    • Cryoprecipitate Cryoprecipitate Transfusion Products
  • Vasopressors Vasopressors Sepsis in Children
• Immediate delivery if woman is still pregnant

Complications

• Hematologic: DIC DIC Disseminated intravascular coagulation (DIC) is a condition characterized by systemic bodywide activation of the coagulation cascade. This cascade results in both widespread microvascular thrombi contributing to multiple organ dysfunction and consumption of clotting factors and platelets, leading to hemorrhage. Disseminated Intravascular Coagulation
• Cardiovascular: hemorrhage and cardiac arrest Cardiac arrest Cardiac arrest is the sudden, complete cessation of cardiac output with hemodynamic collapse. Patients present as pulseless, unresponsive, and apneic. Rhythms associated with cardiac arrest are ventricular fibrillation/tachycardia, asystole, or pulseless electrical activity. Cardiac Arrest
• Pulmonary-related: pulmonary edema Edema Edema is a condition in which excess serous fluid accumulates in the body cavity or interstitial space of connective tissues. Edema is a symptom observed in several medical conditions. It can be categorized into 2 types, namely, peripheral (in the extremities) and internal (in an organ or body cavity). Edema and ARDS
• Permanent neurologic deficits Neurologic Deficits High-Risk Headaches due to cerebral hypoxia Hypoxia Sub-optimal oxygen levels in the ambient air of living organisms. Ischemic Cell Damage (85% of survivors)