Jumat, 23 Juli 2010

ANTEPARTUM HAEMORRHAGE

Antepartum Haemorrhage

Antepartum haemorrhage (APH) is defined as bleeding from the birth canal after the 24th week (some authors define as 20th week) of pregnancy.1 Women with APH should always be admitted to hospital for assessment and management. Miscarriage (Spontaneous Abortion) is discussed in a separate article.

Epidemiology2

  • Affects 3-5% of all pregnancies.
  • 3 times more common in multiparous than primiparous women.

Causes1,3

  • No definite cause is diagnosed in about 40% of all women who present with APH.
  • Placenta praevia:4,5 insertion of the placenta, partially or fully, in the lower segment of the uterus. There are four grades:
    • Grade I: placenta encroaches lower segment but does not reach the cervical os.
    • Grade II: reaches cervical os but does not cover it.
    • Grade III: covers part of the cervical os.
    • Grade IV: completely covers the os, even when the cervix is dilated.
  • Placental abruption (30% of all cases of antepartum haemorrhage):1,6
    • Normal placenta separates from the uterus prematurely and blood collects between the placenta and the uterus.
    • It is estimated to occur in 6.5 pregnancies per 1,000 births.
    • The cause of placental abruption is unknown.
    • Risk factors for placental abruption include:
      • Increasing maternal age and parity
      • High blood pressure (140/90 or greater)
      • Trauma (usually a car accident or maternal battering)
      • Cocaine use
      • Smoking
      • Prolonged rupture of membranes
      • Abruption in previous pregnancies (10% recurrence risk)
  • Local causes, e.g. vulval or cervical infection, trauma or tumours.
  • Vasa praevia (bleeding from fetal vessels in the fetal membranes):7
    • Occurs in about 1 of every 1,000 pregnancies.
    • The baby's blood vessels from the umbilical cord may attach to the membranes instead of the placenta.
  • Uterine rupture:8,9,10
    • Rare but very dangerous for both mother and baby.
    • About 40% of women who have uterine rupture had prior surgery of their uterus, including caesarean section.
    • Other risk factors for uterine rupture are these conditions:
    • The rupture may occur before or during labour or at the time of delivery.
  • Inherited bleeding problems are very rare, occurring in 1 in 10,000 women.11

Presentation

Placenta praevia1,4

  • First episode of bleeding occurs:
    • After 36th week: 60%
    • 32-36th week: 30%
    • Before 32nd week: 10%
  • Bleeding is painless and recurrent.
  • Presenting part is usually high and not central to the pelvic brim.
  • Diagnosis is by ultrasound showing that the placenta is praevia. Transvaginal ultrasound is safe in the presence of placenta praevia and is more accurate than transabdominal ultrasound in locating the placenta.
  • Placenta praevia is the main risk factor for placenta accreta (an abnormally firm attachment of the placenta to the uterine wall). Antenatal imaging by colour flow doppler ultrasound should be performed in women with placenta praevia who are at a particularly increased risk of placenta accreta (anterior placenta praevia and have previously been delivered by caesarean section). Where this is not possible locally, the woman should be managed as if they have placenta accreta until proven otherwise.

Placental abruption1,12

  • May present with vaginal bleeding, abdominal pain, uterine contraction, shock or fetal distress.
  • May not be demonstrable on ultrasound as the blood clot is not easily distinguishable from the placenta.
  • Moderate placental detachment and haemorrhage: at least one quarter of placenta has become detached and less than 1,000 ml of blood lost. Abdominal pain and tender uterus, mother may be in shock, fetus is hypoxic and may show abnormal heart rate patterns.
  • Severe placental detachment and haemorrhage: at least 1,500 ml of blood lost, shock usual, uterus firm-to-hard and very tender. Fetus almost always dead. Hypotension in 1/3 of cases but may be normal in spite of shock. Coagulopathy is common.

Management1

Always admit to hospital for assessment and management. Phone 999 if any major concerns regarding maternal or fetal wellbeing.

  • The mainstays of management are resuscitation and accurate diagnosis of the underlying cause.13
  • Severe bleeding or fetal distress: urgent delivery of baby irrespective of gestational age.
  • Admit to hospital, even if bleeding is only a very small amount. There may be a large amount of concealed bleeding with only a small amount of revealed vaginal bleeding.
  • No vaginal examination should be attempted at least until a placenta praevia is excluded by ultrasound. May initiate torrential bleeding from a placenta praevia.1
  • Resuscitation can be inadequate because of under-estimation of blood loss and misleading maternal response. A young woman may maintain a normal blood pressure until sudden and catastrophic decompensation occurs.14
  • Take blood for full blood count and clotting studies. Cross match as heavy loss may require transfusion.
  • Gentle palpation of the abdomen to determine gestational age of fetus, presentation and position.
  • Fetal monitoring.
  • Arrange urgent ultrasound.
  • With every episode of bleeding, a Rhesus negative woman should have a Kleihauer test and be given prophylactic anti-D immunoglobulin.15

Further management

  • Further management will depend on fetal distress, the cause of the APH, extent of bleeding and gestation.
  • In slight haemorrhage with blood loss less than 500 ml and no disturbance of maternal or fetal condition, ultrasound shows placenta not lying in lower uterine segment, no retroplacental clots, patient may be discharged or have baby induced if after 37 weeks and other conditions suitable.
  • Placenta praevia:4,5
    • Grades I and II may be able to deliver vaginally; Grades III and IV will require caesarean section by a senior obstetrician. Cervical cerclage may reduce very premature births but the evidence is not strong. There is little evidence of advantages or disadvantages to prolonged hospitalisation for placenta praevia.12
    • Women with major placenta praevia who have previously bled should be admitted and managed as inpatients from 34 weeks of gestation.
    • Women with major placenta praevia who remain asymptomatic, having never bled, require careful counselling before contemplating outpatient care. Any home-based care requires close proximity with the hospital, the constant presence of a companion and full informed consent from the woman.4
    • The mode of delivery should be based on clinical judgement supplemented by ultrasound findings. A placental edge less than 2 cm from the internal os is likely to need delivery by caesarean section, especially if it is posterior or thick.4
    • For pre-term delivery when immediate delivery is not necessary, maternal steroids may be indicated in order to promote fetal lung development and reduce the risk of respiratory distress syndrome.16
  • Moderate or severe placental abruption:12,17
    • Restore blood loss, prevent coagulopathy, monitor urinary output. In moderate cases, give 1,500 ml of blood and in severe cases, give 2,500 ml (first 500 ml transfused rapidly). Ideally measure central venous pressure (CVP) and adjust transfusion accordingly.
    • Measure venous blood for coagulation 2 hourly, treat accordingly.
    • Measure urine output 2 hourly. Oliguria may occur but if sufficient blood has been given, then diuresis will follow birth.
    • If fetus is alive, perform either caesarean section or artificial rupture of the amniotic membranes (restore blood volume first). Monitor fetus and switch to caesarean if fetal distress develops.
    • Vaginal delivery is the treatment of choice in the presence of a dead fetus.

Complications1

  • Premature labour
  • Disseminated intravascular coagulopathy
  • Renal tubular necrosis
  • Postpartum haemorrhage
  • Placenta accreta: complicates approximately 10% of all cases of placenta praevia, rare in the absence of placenta praevia4

Prognosis14

  • One study found that bleeding in the second half of pregnancy is an independent risk factor for perinatal mortality.18
  • The fetus may die from hypoxia during heavy bleeding.
  • Perinatal mortality less than 50 per 1,000 maternal mortality is low if managed by experienced obstetrician and no vaginal examination performed before admission to hospital.

Document references

  1. El-Mowafi D; Bleeding in Late Pregnancy (Antepartum Haemorrhage) Geneva Foundation for Medical Education and Research 2008.
  2. Mehboob, R, Ahmad N; Fetal outcome in major degree placenta praevia Pakistan J. Med. Res. Vol. 42 No.1, 2003.
  3. Department of Reproductive Health and Research (RHR); Managing Complications in Pregnancy and Childbirth, World Health Organisation 2003.
  4. Placenta Praevia and Placenta Praevia Accreta: Diagnosis and Management, Royal College of Obstretricians and Gynaecologists (2005)
  5. NICE Clinical Guideline; Antenatal care: routine care for the healthy pregnant woman. March 2008.
  6. Neilson JP; Interventions for treating placental abruption. Cochrane Database Syst Rev. 2003;(1):CD003247. [abstract]
  7. Lijoi AF, Brady J; Vasa previa diagnosis and management; J Am Board Fam Pract. 2003 Nov-Dec;16(6):543-8. [abstract]
  8. Walsh CA, O'Sullivan RJ, Foley ME; Unexplained prelabor uterine rupture in a term primigravida. Obstet Gynecol. 2006 Sep;108(3 Pt 2):725-7. [abstract]
  9. Walsh CA, Baxi LV; Rupture of the primigravid uterus: a review of the literature. Obstet Gynecol Surv. 2007 May;62(5):327-34; quiz 353-4. [abstract]
  10. Leung AS, Farmer RM, Leung EK, et al; Risk factors associated with uterine rupture during trial of labor after cesarean delivery: a case-control study. Am J Obstet Gynecol. 1993 May;168(5):1358-63. [abstract]
  11. Kadir RA, Aledort LM; Obstetrical and gynaecological bleeding: a common presenting symptom. Clin Lab Haematol. 2000 Oct;22 Suppl 1:12-6; discussion 30-2. [abstract]
  12. Neilson JP; Interventions for suspected placenta praevia. Cochrane Database Syst Rev. 2003;(2):CD001998. [abstract]
  13. Sinha P, Kuruba N; Ante-partum haemorrhage: an update. J Obstet Gynaecol. 2008 May;28(4):377-81. [abstract]
  14. Crochetiere C; Obstetric emergencies; Anesthesiol Clin North America. 2003 Mar;21(1):111-25. [abstract]
  15. Use of Anti-D for Rh Prophylaxis Guideline, Royal College of Obstetricians and Gynaecologists (2002)
  16. Antenatal Corticosteroids to Prevent Respiratory Distress Syndrome, Royal College of Obstetricians and Gynaecologists (2004)
  17. Papp Z; Massive obstetric hemorrhage. J Perinat Med. 2003;31(5):408-14. [abstract]
  18. Koifman A, Levy A, Zaulan Y, et al; The clinical significance of bleeding during the second trimester of pregnancy. Arch Gynecol Obstet. 2008 Jul;278(1):47-51. Epub 2007 Dec 8. [abstract]

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