Ante Partum Hemorrhage / Late pregnancy bleeding Flashcards
Source of bleeding during pregnancy is virtually never ________.
fetal
Common origins/sites of bleeding
- disruption of blood vessels in the decidua (pregnancy endometrium)
- lesions in cervix or vagina
Define Antepartum hemorrhage
Vaginal bleeding that occurs after 20wks gestation & unrelated to labor & delivery
Major causes of Antepartum Hemorrhage
- Placenta praevia (20%)
- Placenta abruption (30%)
- Uterine rupture (rare)
- Vasa praevia (rare)
Minor causes of Antepartum Hemorrhage
- Cervical = polyps, infection (cervicitis), carcinoma.
- Vaginal = infection (vaginitis), vaginal warts, vaginal cancer, trauma.
- Uterine pathology = leiomyoma (fibroids), polyps.
- Trauma
- Bloody show = passage of operculum (mucous plug)
Define Placenta Praevia
Implantation of the placenta in the lower segment of the uterus so that it partially or totally covers the internal os of the cervix.
Prevalence of Placenta Praevia
Approx. 4 per 1000 births but varies worldwide.
Placenta Praevia is higher at 20 weeks than at birth because of?
Because the placenta migrates upwards as gestation advances.
Major risk factors - Placenta Praevia
- Previous placenta praevia (4 - 8% recurrence)
- Previous caesarian delivery (increase risk 47 - 60%)
- Multiple gestations (40% higher risk compared to single)
Other risk factors - Placenta Praevia
- Previous uterine surgical procedures
- Increasing parity
- Increasing maternal age
- Infertility treatment
- Previous pregnancy termination
- Maternal smoking
- Male fetus
- Maternal cocaine use
- Prior uterine artery embolization
Placental bleeding is a major sequelae. What does this mean?
Means it results from a prior disease, injury or trauma to the body.
Partial detachment of placenta are due to shearing forces from:
- changes in cervix & lower uterine segment
- vaginal examination (digital examination) = iatrogenic
- coitus (sex)
Where does the bleeding occur in placenta praevia?
Bleeding primarily maternal blood in the intervillous space
Ultrasound examination of placenta praevia
- asymptomatic (incidental) finding
- 16-20wks
- gestational age, fetal anatomy & cervical length
90% placenta praevia on ultrasound before 20 weeks resolves before delivery. Why is this?
- This is because the lower segment lengthens (5mm at 20wks to 50mm at term) & relocates lower edge of placenta away from os.
- Placenta trophotropism = with less vascular lower segment, the placenta tends to migrate upwards to more vascular decidua.
Placenta trophotropism
Process by which the placenta migrates upwards from a less vascular lower segment to a more vascular decidua.
The more the placenta extends over the _____ _____, the more likely it is to ________ until ______.
internal os, persist, delivery
Bleeding in placenta praevia
- Painless (90%):
1/3 initial onset <30wks
1/3 initial onset between 30wks-36wks
1/3 initial onset >36wks - Unpredictable & may occur at any time without warning
- May range from slight intermittent bleeding to heavy profuse bleeding
- Uterine contractions & pain may occur (10 - 20%)
Classification of placenta praevia (3)
- Marginal - placenta is positioned at the edge of the cervix.
- Partial - placenta partially covers the internal os.
- Total - complete coverage of the internal os by the placenta.
Diagnosis of Placenta Praevia
- Clinical suspicion
- vaginal bleeding (painless) after 20wks of gestation
- persistent abnormal fetal lie = transverse, oblique
- Ultrasonography - gold standard
Goal of managing Placenta Praevia
To keep pregnancy intrauterine until risk of continuing pregnancy outweighs risk of preterm delivery.
(prolonging pregnancy to get as close as to the due date without complications)
What examination is not performed in a patient with Placenta Praevia, & why?
Vaginal exam - bc it may exacerbate bleeding when the placenta is disturbed, therefore an ultrasound scan (excludes placenta praevia) is always done before considering a vaginal exam.
Management of Placenta Praevia
- Stabilize & monitor mother
- Admit patient
- Insert a large bore IV cannula = for FBC, Blood group, Rhesus, Crossmatch (blood transfusion)
- Ultrasound to confirm diagnosis
Management of Placenta Praevia (4)
- Less than 37wks & minimal bleeding
- Expectant management
- Limited physical activity, no vaginal douching or sexual intercourse
- Consider corticosteroids for fetal lung maturity (helps mature the development of the lungs)
- Deliver when fetus is mature or hemorrhage threatening fetal or maternal wellbeing.
Management of Placenta Praevia
- Greater than 37wks
Deliver = mode of delivery is to be determined by degree of placenta praevia:
- complete placenta praevia = caesarian section
- low lying placenta = may consider trial of vaginal delivery.
Placenta Abruption
(abruptio placentae)
Partial or complete placental detachment from the uterine wall after 20wks of gestation.
Placenta Abruption - complicates approx. _______ per _____ births.
2-10 per 1000 births
Pathophysiology of Placenta Abruption
Rupture of placental vessels in the decidua basalis (basal layer) → accumulating blood splits the decidua from its placental attachment → leads to the development of potentially life-threatening complications = severe bleeding, maternal DIC (disseminated intravascular coagulation), fetal compromise.
Placenta Abruption - Risk factors
- previous abruption
- hypertension/preeclampsia
- multiparity
- increased age
- smoking/alcohol use
- cocaine use
- polyhydramnios
- premature rupture of membranes
- external trauma
- uterine anomalies (bicornuate uterus/ uterine synaechae/ leiomyomata)
Clinical Features of Placenta Abruption
- pain = sudden onset, constant, localized to uterus & lower back.
- painful vaginal bleeding (80%)
- external/revealed = presents with vaginal bleeding
- internal/concealed (20%) = may or may not present with vaginal bleeding.
- uterine tenderness/ uterine contractions/ hypertonus (uterus doesn’t relax between contractions)
- shock/anemia = out of proportion to external blood loss
- fetal distress/ fetal demise/ bloody amniotic fluid
- couvelaire uterus = extravasation of blood into the uterine musculature and beneath the uterine peritoneum.
Placenta Abruption - 2 main types
- Revealed
- bleeding tracks down from the site of placental separation & drains through the cervix
- results in vaginal bleeding - Concealed
- bleeding remains within the uterus, and typically forms a clot retroplacentally (behind).
- bleeding is not visible but can be severe enough to cause systemic shock.
Management of Placenta Abruption
- Maternal stabilization
- large bore IV with fluids = FBC, Group, Crossmatch, Coagulation profile.
- monitoring of vital signs, urine output, blood loss.
Management of Placenta Abruption
- Fetal monitoring
Cardiotocogram (CTG)
Management of Placenta Abruption
- Abruption without fetal/maternal compromise (mild)
<37 wks
- close monitoring
- deliver when fetus is mature or signs of fetal/maternal compromise
> 37 wks
- deliver
Complications of Placenta Abruption
- Maternal
- hypovolemic shock
- DIC = disseminated intravascular coagulation
- blood transfusion
- hysterectomy (removal of uterus)
- renal failure
- in hospital death
Complications of Placenta Abruption
- Fetal
- non-reassuring status
- growth restriction
- death
Complications of Placenta Abruption
- Newborn
- pre-term birth
- small for gestational age
- death
Vasa Previa
Rare condition where one of the branches of the fetal umbilical vessels lies in the membranes & across the cervical os.
If vasa praevia is undiagnosed…
50% perinatal mortality, increasing to 75% if membranes rupture.
If vasa praevia is diagnosed antenatally using ultrasound without labour or symptoms…
97% survival
Management of Vasa Praevia
- Planned c-section delivery at 37wks
- Emergency c-section if bleeding earlier
Rupture of uterus can occur?
*During pregnancy - before or after the onset of labor.
- Spontaneously
- previous caesarian scar (classical c/section more than lower segment c/section)
- uterine anomaly
- intact uterus (rare)
- as a side effect of uterotonic agents (oxytocin)
*Acquired
- trauma (car accidents, physical violence)
- obstetrics procedures (e.g. forceps rotation, external cephalic version)
Rupture of the uterus may lead to ____ of both ____ & ____.
death, mother, fetus
Clinical features - Rupture of uterus
- high index of suspicion
- vaginal bleeding
- absence of contractions in a woman who was contracting regularly
- abdominal distension
- fetal distress & possibly death
- maternal reduction in level of consciousness & shock
Management - Rupture of the uterus
- Obstetrics emergency
- Multidisciplinary team effort
- ABC
- Stabilize woman & transfer for urgent laparotomy - uterine repair vs hysterectomy.
Complications of Rupture of the uterus
- Fetal
- hypoxia
- acidosis
- NICU admission
- death
Complications of Rupture of the uterus
- Maternal
- severe blood loss
- blood transfusion
- surgical risk with possible hysterectomy
- death
