Antepartum Hemorrhage

Antepartum hemorrhage is defined as vaginal bleeding that occurs after 20 weeks of gestation and is unrelated to labor Labor Labor is the normal physiologic process defined as uterine contractions resulting in dilatation and effacement of the cervix, which culminates in expulsion of the fetus and the products of conception. Normal and Abnormal Labor. The most important causes are placental abruption (most common), placenta Placenta The placenta consists of a fetal side and a maternal side, and it provides a vascular communication between the mother and the fetus. This communication allows the mother to provide nutrients to the fetus and allows for removal of waste products from fetal blood. Placenta, Umbilical Cord, and Amniotic Cavity previa (2nd most common), vasa previa, and uterine rupture. Placental abruption and uterine rupture are diagnosed clinically. Placenta previa and vasa previa are usually diagnosed as part of routine screening on a midtrimester ultrasound, and digital exams in these women must be avoided. All of these conditions can lead to maternal and/or fetal hemorrhage, necessitating emergency C-section and maternal and/or fetal resuscitation.

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Editorial responsibility: Stanley Oiseth, Lindsay Jones, Evelin Maza

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Overview

Definition

Antepartum hemorrhage is defined as vaginal bleeding that occurs after 20 weeks’ gestation and is unrelated to labor Labor Labor is the normal physiologic process defined as uterine contractions resulting in dilatation and effacement of the cervix, which culminates in expulsion of the fetus and the products of conception. Normal and Abnormal Labor.

Epidemiology and etiology

  • Incidence: occurs in approximately 5% of pregnancies 
  • Most common etiologies:
    • Placental abruption: 30%
    • Placenta previa: 20%
  • The etiology is often not determined.
Table: Causes of antepartum bleeding by location
Anatomic location Causes of antepartum bleeding
Placenta
  • Placental abruption*
  • Placenta previa*
  • Vasa previa*
Uterus Uterus The uterus, cervix, and fallopian tubes are part of the internal female reproductive system. The uterus has a thick wall made of smooth muscle (the myometrium) and an inner mucosal layer (the endometrium). The most inferior portion of the uterus is the cervix, which connects the uterine cavity to the vagina. Posterior Abdominal Wall Uterine rupture*
Cervix
  • “Bloody show”: a small amount of bloody mucus discharge that often precedes labor Labor Labor is the normal physiologic process defined as uterine contractions resulting in dilatation and effacement of the cervix, which culminates in expulsion of the fetus and the products of conception. Normal and Abnormal Labor as the cervix Cervix The uterus, cervix, and fallopian tubes are part of the internal female reproductive system. The most inferior portion of the uterus is the cervix, which connects the uterine cavity to the vagina. Externally, the cervix is lined by stratified squamous cells; however, the cervical canal is lined by columnar epithelium. Posterior Abdominal Wall ripens
  • Cervicitis
    • STIs: gonorrhea Gonorrhea Gonorrhea is a sexually transmitted infection (STI) caused by the gram-negative bacteria Neisseria gonorrhoeae (N. gonorrhoeae). Gonorrhea may be asymptomatic but commonly manifests as cervicitis or urethritis with less common presentations such as proctitis, conjunctivitis, or pharyngitis. Gonorrhea, chlamydia Chlamydia Chlamydiae are obligate intracellular gram-negative bacteria. They lack a peptidoglycan layer and are best visualized using Giemsa stain. The family of Chlamydiaceae comprises 3 pathogens that can infect humans: Chlamydia trachomatis, Chlamydia psittaci, and Chlamydia pneumoniae. Chlamydia
    • Secondary to vaginitis: candidiasis Candidiasis Candida is a genus of dimorphic, opportunistic fungi. Candida albicans is part of the normal human flora and is the most common cause of candidiasis. The clinical presentation varies and can include localized mucocutaneous infections (e.g., oropharyngeal, esophageal, intertriginous, and vulvovaginal candidiasis) and invasive disease (e.g., candidemia, intraabdominal abscess, pericarditis, and meningitis). Candida/Candidiasis, bacterial vaginosis
  • Cervical ectropion: exposed cervical columnar 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 that is prone to light bleeding when touched
  • Polyps
  • Carcinoma
Vagina 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
  • Varicosities
  • Vaginitis
  • Lacerations
  • Carcinoma
*Clinically important obstetric cause.

Placental Abruption

Overview

Placental abruption is the complete or partial premature detachment of a normally implanted placenta Placenta The placenta consists of a fetal side and a maternal side, and it provides a vascular communication between the mother and the fetus. This communication allows the mother to provide nutrients to the fetus and allows for removal of waste products from fetal blood. Placenta, Umbilical Cord, and Amniotic Cavity before the birth of the infant.

Clinical relevance:

  • With a detached placenta Placenta The placenta consists of a fetal side and a maternal side, and it provides a vascular communication between the mother and the fetus. This communication allows the mother to provide nutrients to the fetus and allows for removal of waste products from fetal blood. Placenta, Umbilical Cord, and Amniotic Cavity:
    • The infant is no longer able to get oxygen.
    • Maternal and fetal hemorrhage occurs through the placenta Placenta The placenta consists of a fetal side and a maternal side, and it provides a vascular communication between the mother and the fetus. This communication allows the mother to provide nutrients to the fetus and allows for removal of waste products from fetal blood. Placenta, Umbilical Cord, and Amniotic Cavity.
  • An obstetric emergency that usually requires immediate delivery

Epidemiology

  • Incidence: approximately 2–10 per 1000 births
  • Age: more common in women < 20 and > 35 years of age
  • Gestational age at abruption:
    • Term: 60%
    • 32–36 weeks: 25%
    • < 32 weeks: 15%

Risk factors

  • Previous abruption (strongest risk factor)
  • Hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension
    • Preeclampsia
    • Poorly controlled chronic hypertension
  • Trauma to the abdomen
  • Cocaine or tobacco use
  • Quick decompression of the uterus
    • Rupture of membranes in a pregnancy Pregnancy Pregnancy is the time period between fertilization of an oocyte and delivery of a fetus approximately 9 months later. The 1st sign of pregnancy is typically a missed menstrual period, after which, pregnancy should be confirmed clinically based on a positive β-HCG test (typically a qualitative urine test) and pelvic ultrasound. Pregnancy: Diagnosis, Maternal Physiology, and Routine Care with polyhydramnios Polyhydramnios Polyhydramnios is a pathological excess of amniotic fluid. Common causes of polyhydramnios include fetal anomalies, gestational diabetes, multiple gestations, and congenital infections. Patients are often asymptomatic but may present with dyspnea, extremity swelling, or abdominal distention. Polyhydramnios
    • Delivery of the 1st infant in a multiple gestation
  • Fetal growth restriction Fetal growth restriction Fetal growth restriction (FGR), also known as intrauterine fetal growth restriction (IUGR), is an estimated fetal weight (EFW) or abdominal circumference < 10th percentile for gestational age. The term small for gestational age (SGA) is sometimes erroneously used interchangeably with FGR. Fetal Growth Restriction (may suggest a small chronic partial abruption)
  • Uterine anomalies 
    • Leiomyomas
    • Bicornuate uterus

Etiology

  • Unknown, but likely related to: 
    • Chronic placental disease processes 
    • Abnormalities in the development of placental vasculature
  • Direct abdominal trauma (less common)

Pathophysiology

  • Rupture of maternal vessels in the decidua basalis → accumulation of blood splits the decidua → a thin layer of decidua is separated off with its placental attachment
  • Thrombin is a potent uterotonic agent → clotting in the decidua triggers uterine contractions
  • Complete abruption:
    • Caused by high-pressure arterial hemorrhage in the center of the placenta Placenta The placenta consists of a fetal side and a maternal side, and it provides a vascular communication between the mother and the fetus. This communication allows the mother to provide nutrients to the fetus and allows for removal of waste products from fetal blood. Placenta, Umbilical Cord, and Amniotic Cavity
    • Life-threatening for fetus and mother
  • Partial abruption:
    • Caused by low-pressure venous hemorrhage, usually at the periphery of the placenta Placenta The placenta consists of a fetal side and a maternal side, and it provides a vascular communication between the mother and the fetus. This communication allows the mother to provide nutrients to the fetus and allows for removal of waste products from fetal blood. Placenta, Umbilical Cord, and Amniotic Cavity
    • Often self-limited, with only a small area of separation
    • Can lead to “chronic abruption” throughout the remainder of pregnancy Pregnancy Pregnancy is the time period between fertilization of an oocyte and delivery of a fetus approximately 9 months later. The 1st sign of pregnancy is typically a missed menstrual period, after which, pregnancy should be confirmed clinically based on a positive β-HCG test (typically a qualitative urine test) and pelvic ultrasound. Pregnancy: Diagnosis, Maternal Physiology, and Routine Care

Clinical presentation

  • Bleeding may be:
    • External with visible vaginal bleeding (80%) OR
    • Concealed (blood pools behind the placenta Placenta The placenta consists of a fetal side and a maternal side, and it provides a vascular communication between the mother and the fetus. This communication allows the mother to provide nutrients to the fetus and allows for removal of waste products from fetal blood. Placenta, Umbilical Cord, and Amniotic Cavity) without vaginal bleeding (20%)
  • Painful bleeding:
    • Abdominal and/or back pain Back pain Back pain is a common complaint among the general population and is mostly self-limiting. Back pain can be classified as acute, subacute, or chronic depending on the duration of symptoms. The wide variety of potential etiologies include degenerative, mechanical, malignant, infectious, rheumatologic, and extraspinal causes. Back Pain
    • Bleeding can range from mild to life-threatening.
  • Contractions (often hypertonic or high-frequency)
  • Uterine tenderness
  • Fetal distress/decreased fetal movement
  • Small, partial abruptions may be less dramatic and present with:
    • Smaller amounts of bleeding over time (chronic abruptions)
    • Oligohydramnios Oligohydramnios Oligohydramnios refers to amniotic fluid volume less than expected for the current gestational age. Oligohydramnios is diagnosed by ultrasound and defined as an amniotic fluid index (AFI) of ‰¤ 5 cm or a single deep pocket (SDP) of < 2 cm in the 2nd or 3rd trimester. Oligohydramnios
    • Intrauterine fetal growth restriction
Placental abruption

Placental abruption:
External versus concealed bleeding

Image: “Placental abruption” by BruceBlaus. License: Public Domain

Diagnosis

The diagnosis of placental abruption is usually clinical, based on the history, exam, and fetal monitoring Fetal monitoring The primary goals of antepartum testing and monitoring are to assess fetal well-being, identify treatable situations that may cause complications, and evaluate for chromosomal abnormalities. These tests are divided into screening tests (which include cell-free DNA testing, serum analyte testing, and nuchal translucency measurements), and diagnostic tests, which provide a definitive diagnosis of aneuploidy and include chorionic villus sampling (CVS) and amniocentesis. Antepartum Testing and Monitoring.

  • Fetal nonstress test:
    • Measures fetal heart rate and uterine contractions (tocometry)
    • Used to assess fetal status
    • Signs of fetal distress: bradycardia, ↓ heart rate variability, late decelerations
    • Tocometry: frequent and/or hypertonic contractions
  • Ultrasonography:
    • Exclude placenta Placenta The placenta consists of a fetal side and a maternal side, and it provides a vascular communication between the mother and the fetus. This communication allows the mother to provide nutrients to the fetus and allows for removal of waste products from fetal blood. Placenta, Umbilical Cord, and Amniotic Cavity previa
    • May show a retroplacental hematoma
    • Low sensitivity, but decent specificity 
  • Laboratory: helpful in managing acute resuscitation, rather than diagnosis of abruption itself
    • Kleihauer-Betke test: can detect fetal RBCs in maternal circulation
    • Type and cross
    • CBC → evaluate degree of 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
    • Coagulation panel: PT, PTT, fibrinogen → evaluate for 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

Management

  • Severe abruption:
    • Needed in individuals with 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, hypovolemic shock Shock Shock is a life-threatening condition associated with impaired circulation that results in tissue hypoxia. The different types of shock are based on the underlying cause: distributive (↑ cardiac output (CO), ↓ systemic vascular resistance (SVR)), cardiogenic (↓ CO, ↑ SVR), hypovolemic (↓ CO, ↑ SVR), obstructive (↓ CO), and mixed. Types of Shock, or nonreassuring fetal status
    • Step 1: stabilization
      • Establish 2 large-bore IV lines.
      • Initiate IV fluids IV fluids Intravenous fluids are one of the most common interventions administered in medicine to approximate physiologic bodily fluids. Intravenous fluids are divided into 2 categories: crystalloid and colloid solutions. Intravenous fluids have a wide variety of indications, including intravascular volume expansion, electrolyte manipulation, and maintenance fluids. Intravenous Fluids.
      • Transfuse blood products as needed.
    • Step 2: emergent 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
  • Mild or chronic abruption:
    • Monitor and observe the mother to ensure the abruption remains stable.
    • Frequent assessments of fetal well-being
    • Corticosteroids (betamethasone) for fetal lung maturity in premature infants
    • Deliver if mother or infant decompensates.

Complications

  • Maternal complications:
    • 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 
    • Renal failure
    • ARDS ARDS Acute respiratory distress syndrome is characterized by the sudden onset of hypoxemia and bilateral pulmonary edema without cardiac failure. Sepsis is the most common cause of ARDS. The underlying mechanism and histologic correlate is diffuse alveolar damage (DAD). Acute Respiratory Distress Syndrome
    • Peripartum hysterectomy
    • Complications associated with blood transfusions
    • Increased risk of cardiovascular disease later in life
  • Fetal complications:
    • Complications of hypoxemia (e.g., neurologic impairment)
    • Complications of prematurity (e.g., respiratory distress, intraventricular hemorrhage, retinopathy of prematurity Retinopathy of prematurity Retinopathy of prematurity (ROP) is a condition seen in premature infants of low birth weight that is characterized by progressive and excessive neovascularization. In this condition, the inappropriate proliferation of blood vessels and fibrovascular tissue behind the lens prevents retinal development. Retinopathy of Prematurity)
    • Fetal growth restriction Fetal growth restriction Fetal growth restriction (FGR), also known as intrauterine fetal growth restriction (IUGR), is an estimated fetal weight (EFW) or abdominal circumference < 10th percentile for gestational age. The term small for gestational age (SGA) is sometimes erroneously used interchangeably with FGR. Fetal Growth Restriction (chronic partial abruption)

Placenta Previa

Overview

Placenta previa is a condition in which the placenta Placenta The placenta consists of a fetal side and a maternal side, and it provides a vascular communication between the mother and the fetus. This communication allows the mother to provide nutrients to the fetus and allows for removal of waste products from fetal blood. Placenta, Umbilical Cord, and Amniotic Cavity implants in the lower uterine segment, near or covering the internal cervical os.

Definitions:

  • Low-lying placenta Placenta The placenta consists of a fetal side and a maternal side, and it provides a vascular communication between the mother and the fetus. This communication allows the mother to provide nutrients to the fetus and allows for removal of waste products from fetal blood. Placenta, Umbilical Cord, and Amniotic Cavity: the placental edge is < 2 cm from (but not covering) the internal os (managed in the the same way as placenta Placenta The placenta consists of a fetal side and a maternal side, and it provides a vascular communication between the mother and the fetus. This communication allows the mother to provide nutrients to the fetus and allows for removal of waste products from fetal blood. Placenta, Umbilical Cord, and Amniotic Cavity previa)
  • “Marginal” and “partial” placenta Placenta The placenta consists of a fetal side and a maternal side, and it provides a vascular communication between the mother and the fetus. This communication allows the mother to provide nutrients to the fetus and allows for removal of waste products from fetal blood. Placenta, Umbilical Cord, and Amniotic Cavity previa are older terms that should be avoided.

Clinical relevance: 

  • As the cervix Cervix The uterus, cervix, and fallopian tubes are part of the internal female reproductive system. The most inferior portion of the uterus is the cervix, which connects the uterine cavity to the vagina. Externally, the cervix is lined by stratified squamous cells; however, the cervical canal is lined by columnar epithelium. Posterior Abdominal Wall dilates beneath the placenta Placenta The placenta consists of a fetal side and a maternal side, and it provides a vascular communication between the mother and the fetus. This communication allows the mother to provide nutrients to the fetus and allows for removal of waste products from fetal blood. Placenta, Umbilical Cord, and Amniotic Cavity, it exposes the placenta Placenta The placenta consists of a fetal side and a maternal side, and it provides a vascular communication between the mother and the fetus. This communication allows the mother to provide nutrients to the fetus and allows for removal of waste products from fetal blood. Placenta, Umbilical Cord, and Amniotic Cavity → bleeding (both maternal and fetal blood loss)
  • Never perform a digital cervix Cervix The uterus, cervix, and fallopian tubes are part of the internal female reproductive system. The most inferior portion of the uterus is the cervix, which connects the uterine cavity to the vagina. Externally, the cervix is lined by stratified squamous cells; however, the cervical canal is lined by columnar epithelium. Posterior Abdominal Wall exam on a woman with placenta Placenta The placenta consists of a fetal side and a maternal side, and it provides a vascular communication between the mother and the fetus. This communication allows the mother to provide nutrients to the fetus and allows for removal of waste products from fetal blood. Placenta, Umbilical Cord, and Amniotic Cavity previa; you will stick your finger into the placenta Placenta The placenta consists of a fetal side and a maternal side, and it provides a vascular communication between the mother and the fetus. This communication allows the mother to provide nutrients to the fetus and allows for removal of waste products from fetal blood. Placenta, Umbilical Cord, and Amniotic Cavity and cause severe hemorrhage.
Location of the placenta in placenta previa

Location of the placenta Placenta The placenta consists of a fetal side and a maternal side, and it provides a vascular communication between the mother and the fetus. This communication allows the mother to provide nutrients to the fetus and allows for removal of waste products from fetal blood. Placenta, Umbilical Cord, and Amniotic Cavity in placenta Placenta The placenta consists of a fetal side and a maternal side, and it provides a vascular communication between the mother and the fetus. This communication allows the mother to provide nutrients to the fetus and allows for removal of waste products from fetal blood. Placenta, Umbilical Cord, and Amniotic Cavity previa

Image: “Placenta previa” by OpenStax College – Anatomy & Physiology. License: CC BY 3.0

Epidemiology

  • Prevalence: 4 per 1000 births
  • In up to 6% of women, a midtrimester ultrasound will show placenta Placenta The placenta consists of a fetal side and a maternal side, and it provides a vascular communication between the mother and the fetus. This communication allows the mother to provide nutrients to the fetus and allows for removal of waste products from fetal blood. Placenta, Umbilical Cord, and Amniotic Cavity previa.
  • Approximately 90% of placenta Placenta The placenta consists of a fetal side and a maternal side, and it provides a vascular communication between the mother and the fetus. This communication allows the mother to provide nutrients to the fetus and allows for removal of waste products from fetal blood. Placenta, Umbilical Cord, and Amniotic Cavity previas identified at < 20 weeks resolve by delivery.
    • The lower uterine segment lengthens from 0.5 cm at 20 weeks to over 5 cm at term.
    • This lengthening “moves” the placenta Placenta The placenta consists of a fetal side and a maternal side, and it provides a vascular communication between the mother and the fetus. This communication allows the mother to provide nutrients to the fetus and allows for removal of waste products from fetal blood. Placenta, Umbilical Cord, and Amniotic Cavity away from the os.
  • Complete placenta Placenta The placenta consists of a fetal side and a maternal side, and it provides a vascular communication between the mother and the fetus. This communication allows the mother to provide nutrients to the fetus and allows for removal of waste products from fetal blood. Placenta, Umbilical Cord, and Amniotic Cavity previa is unlikely to resolve.

Risk factors

  • Most important risk factors:
    • Previous placenta Placenta The placenta consists of a fetal side and a maternal side, and it provides a vascular communication between the mother and the fetus. This communication allows the mother to provide nutrients to the fetus and allows for removal of waste products from fetal blood. Placenta, Umbilical Cord, and Amniotic Cavity previa
    • Previous C-section
    • Multiple gestation
  • Other risk factors:
    • Previous curettage
    • Previous or recurrent abortions
    • Infertility Infertility Infertility is the inability to conceive in the context of regular intercourse. The most common causes of infertility in women are related to ovulatory dysfunction or tubal obstruction, whereas, in men, abnormal sperm is a common cause. Infertility treatment
    • Advanced maternal age (> 35 years old)
    • Multiparity
    • Uterine structural anomaly 
    • Smoking 
    • Cocaine use

Clinical presentation

  • Painless vaginal bleeding
  • Fetal distress
  • Usually asymptomatic until cervical dilation begins after 30 weeks

Diagnosis

  • Transvaginal ultrasonography:
    • Shows placenta Placenta The placenta consists of a fetal side and a maternal side, and it provides a vascular communication between the mother and the fetus. This communication allows the mother to provide nutrients to the fetus and allows for removal of waste products from fetal blood. Placenta, Umbilical Cord, and Amniotic Cavity near or covering the cervical os
    • Usually diagnosed on routine midtrimester ultrasound
    • Assessing placental location is a recommended part of routine obstetric care.
  • Avoid digital exams on a woman with placenta Placenta The placenta consists of a fetal side and a maternal side, and it provides a vascular communication between the mother and the fetus. This communication allows the mother to provide nutrients to the fetus and allows for removal of waste products from fetal blood. Placenta, Umbilical Cord, and Amniotic Cavity previa.
Placenta previa on ultrasound

Transabdominal ultrasound showing placenta Placenta The placenta consists of a fetal side and a maternal side, and it provides a vascular communication between the mother and the fetus. This communication allows the mother to provide nutrients to the fetus and allows for removal of waste products from fetal blood. Placenta, Umbilical Cord, and Amniotic Cavity previa
P = placenta Placenta The placenta consists of a fetal side and a maternal side, and it provides a vascular communication between the mother and the fetus. This communication allows the mother to provide nutrients to the fetus and allows for removal of waste products from fetal blood. Placenta, Umbilical Cord, and Amniotic Cavity
CX = cervix Cervix The uterus, cervix, and fallopian tubes are part of the internal female reproductive system. The most inferior portion of the uterus is the cervix, which connects the uterine cavity to the vagina. Externally, the cervix is lined by stratified squamous cells; however, the cervical canal is lined by columnar epithelium. Posterior Abdominal Wall

Image: “Placenta previa” by Haiyan Yu et al. License: CC BY 4.0

Management

  • Asymptomatic antenatal management:
    • Pelvic rest (no intercourse)
    • Plan to deliver at 36 weeks, prior to the onset of labor Labor Labor is the normal physiologic process defined as uterine contractions resulting in dilatation and effacement of the cervix, which culminates in expulsion of the fetus and the products of conception. Normal and Abnormal Labor.
    • When exam is required, visual assessment with a speculum only
  • If bleeding: emergency C-section to prevent fetal death

Vasa Previa

Overview

Definitions:

  • Velamentous cord: portion of the umbilical cord lacks the protective Wharton’s jelly near the placental insertion site, making the cord prone to rupture:
    • Known as “membranous vessels” because they are attached to the chorion
    • Length of unprotected cord may be several centimeters long
  • Vasa previa: condition in which fetal vessels run across the internal cervical os

Clinical significance:

  • A digital exam may rupture these vessels, causing fetal exsanguination within minutes.
  • Rupture of membranes may rupture the vessels.
  • These vessels may also become compressed by the fetal head.
Vasa previa

Vasa previa

Image: “Vasa previa” by Sigrid de Rooij. License: CC BY-SA 4.0, edited by Lecturio.

Epidemiology

  • Prevalence: 
    • 1% of singleton gestations
    • Up to 15% of monochorionic twin gestations
  • Risk factors: 
    • Accessory (succenturiate) placental lobes
    • Multiple gestation
    • Placenta previa
    • Velamentous cord insertion

Clinical presentation

  • Painless vaginal bleeding (often after rupture of membranes)
  • Fetal distress
  • Women are often asymptomatic until cervical dilation or disruption due to mechanical trauma.

Diagnosis

  • Transvaginal ultrasound with Doppler: 
    • Demonstrates fetal vessels traversing the internal cervical os
    • Assessing the umbilical cord vessels and insertion site at around 20 weeks is a recommended element of routine prenatal care Prenatal care Prenatal care is a systematic and periodic assessment of pregnant women during gestation to assure the best health outcome for the mother and her fetus. Prenatal care prevents and identifies maternal and fetal problems that adversely affect the pregnancy outcome. Prenatal Care.
  • Avoid digital exam on a woman with vasa previa.
Doppler ultrasound of vasa previa

Transvaginal ultrasound showing a vasa previa:
The color Doppler shows blood flowing through the vasa previa vessel over the internal cervical os. The cervical canal is marked with the yellow asterisks on each end.

Image: “Doppler ultrasound of vasa previa” by Division of Reproductive Endocrinology & Infertility Infertility Infertility is the inability to conceive in the context of regular intercourse. The most common causes of infertility in women are related to ovulatory dysfunction or tubal obstruction, whereas, in men, abnormal sperm is a common cause. Infertility, Beth Israel Deaconess Medical Center/Boston IVF, Harvard Medical School, Boston, MA, USA. License: CC BY 3.0

Management

  • Asymptomatic antenatal management:
    • Pelvic rest (no intercourse)
    • Plan to deliver at 36 weeks, prior to the onset of labor Labor Labor is the normal physiologic process defined as uterine contractions resulting in dilatation and effacement of the cervix, which culminates in expulsion of the fetus and the products of conception. Normal and Abnormal Labor.
    • When exam is required, visual assessment with a speculum only
  • If bleeding: emergency C-section to prevent fetal death

Uterine Rupture

Definition

Uterine rupture is a clinically significant disruption in all layers of the uterus, usually through a previous uterine scar.

Epidemiology

  • Incidence in individuals with a prior 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
    • 0.3%
    • More common in women undergoing a trial of labor Labor Labor is the normal physiologic process defined as uterine contractions resulting in dilatation and effacement of the cervix, which culminates in expulsion of the fetus and the products of conception. Normal and Abnormal Labor after cesarean (TOLAC) compared to planned repeat cesarean deliveries
  • Incidence in individuals without a prior uterine scar: 
    • Rare
    • Estimated at 1 per 20,000 pregnancies
  • Perinatal death rate associated with uterine rupture: 5%–25%

Risk factors

  • Prior uterine incision:
    • C-section (most common)
    • Classical (high vertical or fundal) uterine incision (highest risk)
    • Myomectomy
  • TOLAC
  • Induction and augmentation of labor Labor Labor is the normal physiologic process defined as uterine contractions resulting in dilatation and effacement of the cervix, which culminates in expulsion of the fetus and the products of conception. Normal and Abnormal Labor (excessive oxytocin stimulation)

Clinical presentation

  • Abdominal pain Pain Pain has accompanied humans since they first existed, first lamented as the curse of existence and later understood as an adaptive mechanism that ensures survival. Pain is the most common symptomatic complaint and the main reason why people seek medical care. Physiology of Pain (often severe and with sudden onset)
  • Vaginal bleeding (may be light if a majority of blood is lost intraabdominally)
  • Nonreassuring fetal heart rate patterns:
    • Bradycardia
    • Late decelerations
    • Minimal or absent fetal heart rate variability
  • Loss of uterine tone
  • Sudden loss of station of the presenting fetal part
  • Maternal hemodynamic instability
  • May be diagnosed postpartum after a TOLAC with a postpartum hemorrhage Postpartum hemorrhage Postpartum hemorrhage is one of the most common and deadly obstetric complications. Since 2017, postpartum hemorrhage has been defined as blood loss greater than 1,000 mL for both cesarean and vaginal deliveries, or excessive blood loss with signs of hemodynamic instability. Postpartum Hemorrhage that does not respond to uterotonic agents

Diagnosis

  • The diagnosis is clinical, based on presentation and risk factors.
  • Usually, significant fetal distress necessitates immediate action.
  • Diagnosis is confirmed on laparotomy Laparotomy Laparotomy is an open surgical exploration of the abdomen, usually through a single large incision. Laparotomy and Laparoscopy.

Management

  • Immediate emergency 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
  • Concurrent maternal stabilization with IV fluids IV fluids Intravenous fluids are one of the most common interventions administered in medicine to approximate physiologic bodily fluids. Intravenous fluids are divided into 2 categories: crystalloid and colloid solutions. Intravenous fluids have a wide variety of indications, including intravascular volume expansion, electrolyte manipulation, and maintenance fluids. Intravenous Fluids and blood products, as needed
  • Surgical repair of the uterine rupture, following delivery of the infant and maternal stabilization
  • Hysterectomy (last resort in cases of persistent hemorrhage and/or nonrepairable uterus)
Uterine rupture photograph

Uterine rupture:
This woman has undergone a laparotomy Laparotomy Laparotomy is an open surgical exploration of the abdomen, usually through a single large incision. Laparotomy and Laparoscopy through a vertical midline incision. Within the abdominal cavity, a bulging amniotic sac is noted through a large defect in the anterior uterine wall.

Image: “Silent uterine rupture” by Department of Obstetrics and Gynecology, Michigan State University/Sparrow Hospital, Lansing, MI MI MI is ischemia and death of an area of myocardial tissue due to insufficient blood flow and oxygenation, usually from thrombus formation on a ruptured atherosclerotic plaque in the epicardial arteries. Clinical presentation is most commonly with chest pain, but women and patients with diabetes may have atypical symptoms. Myocardial Infarction 48912, USA. License: CC BY 3.0

Comparison of Diagnoses

Table: Comparison of causes of antepartum bleeding
Condition Typical presentation Important risk factors Management
Placental abruption
  • Painful bleeding
  • Contractions
  • Nonreassuring fetal status
  • Hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension
  • Rapid uterine decompression
  • Trauma
  • Cocaine or tobacco use
Emergent delivery
Placenta previa Painless bleeding OR asymptomatic
  • Prior placenta Placenta The placenta consists of a fetal side and a maternal side, and it provides a vascular communication between the mother and the fetus. This communication allows the mother to provide nutrients to the fetus and allows for removal of waste products from fetal blood. Placenta, Umbilical Cord, and Amniotic Cavity previa
  • Prior 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
  • Multiple gestation
  • No digital exams
  • Pelvic rest
  • Deliver with bleeding, or at 36 weeks.
Vasa previa Painless bleeding OR asymptomatic
  • Accessory placental lobe
  • Current placenta Placenta The placenta consists of a fetal side and a maternal side, and it provides a vascular communication between the mother and the fetus. This communication allows the mother to provide nutrients to the fetus and allows for removal of waste products from fetal blood. Placenta, Umbilical Cord, and Amniotic Cavity previa
  • Multiple gestation
  • Velamentous cord
  • No digital exams
  • Pelvic rest
  • Deliver with bleeding, or at 36 weeks.
Uterine rupture
  • Painful bleeding
  • Loss of fetal station
  • Nonreassuring fetal status
  • Prior uterine incision (especially vertical or fundal incisions)
  • TOLAC
  • Induction of labor Labor Labor is the normal physiologic process defined as uterine contractions resulting in dilatation and effacement of the cervix, which culminates in expulsion of the fetus and the products of conception. Normal and Abnormal Labor
  • Emergent delivery
  • Surgical repair of rupture

References

  1. Ananth, C.V., Kinzler, W.L. (2021). Placental abruption: Pathophysiology, clinical features, diagnosis, and consequences. In: Barss, V.A. (Ed.), UpToDate. Retrieved March 12, 2021, from https://www.uptodate.com/contents/placental-abruption-pathophysiology-clinical-features-diagnosis-and-consequences
  2. Deering, S. (2018). Abruptio placentae. Medscape. Retrieved March 12, 2021, from https://emedicine.medscape.com/article/252810-overview 
  3. Lockwood, C.J. (2019). Placenta previa: Epidemiology, clinical features, diagnosis, morbidity, and mortality. UpToDate. Retrieved March 11, 2021, from https://www.uptodate.com/contents/placenta-previa-epidemiology-clinical-features-diagnosis-morbidity-and-mortality
  4. Bakker, R. (2018). Placenta previa. Medscape. Retrieved March 12, 2021, from https://emedicine.medscape.com/article/262063-overview#a4 
  5. Anderson-Bagg, F. (2020). Placenta previa. StatPearls. Retrieved March 11, 2021, from https://www.statpearls.com/articlelibrary/viewarticle/27262/ 
  6. Lockwood, C.J. (2020). Velamentous umbilical cord insertion and vasa previa. UpToDate. Retrieved March 12, 2021, from https://www.uptodate.com/contents/velamentous-umbilical-cord-insertion-and-vasa-previa 
  7. Landon, M.B. (2020). Uterine rupture: after previous cesarean delivery. UpToDate. Retrieved March 12, 2021, from https://www.uptodate.com/contents/uterine-rupture-after-previous-cesarean-delivery

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