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Placenta praevia (placenta previa AE) is an obstetric complication in which the placenta is attached to the uterine wall close to or covering the cervix.

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• Antepartum haemorrhage (APH) is defined as any
  vaginal bleeding occurring during pregnancy,
  starting from 20 weeks gestation until delivery of
  the fetus.

• APH remains one of the leading causes of maternal
  mortality throughout the world. It may also have and
  adverse effect on the fetal and neonatal outcome.

• In many cases the bleeding in APH is unavoidable, and
  if severe an urgent intervention will be life saving both to
  the mother and the fetus.
• I. Maternal (placental site causes):
    –     Bleeding is due to premature separation of the placenta. They
          are the most worrying causes as both the mother and her
          fetus are in danger, it includes:
          •   Placenta praevia (bleeding from separation of an abnormally
              situated placenta).
          •   Placental abruption (bleeding from separation of a normally
              situated placenta).

•       II. Fetal (rupture vasa praevia):
    –     Vasa praevia (velamentous insertion of the cord with rupture
          of fetal vessels).
  (extra-placental site):
 – Local causes are less worrying. They are
   due to local gynecological condition
   • Cervicitis and cervical erosion.
   • Benign cervical polyp or rarely malignant
       cervical carcinoma.
   •   Severe vaginal infections or rarely vaginal
• Placenta praevia (PP) is a placenta that is encroaching on the
  lower uterine segment. It may be located over or very near
  the internal os.

• Placenta praevia is relatively rare (1/300 to 1/500
  pregnancies), however it may be the cause of one of the most
  serious and life threatening obstetric emergencies.

• Placenta praevia may be associated with mild or severe bleeding
  which may be provoked or spontaneous. Such bleeding is from
  maternal and not fetal circulation, and is more likely to
  compromise the mother before it affects fetal condition
•   Total placenta praevia (complete): The placenta completely covers the internal
•   Partial placenta praevia (incomplete): The placenta partially covers the internal
•   Marginal placenta praevia: The edge of the placenta is at the margin of the
    internal os.
•   Low lying placenta (PP lateralis): The placental encroaches on the lower uterine
    segment but its edge does not reach the internal os. (it is of little clinical

•   N.B.: the nearer the placenta to the internal os, the more is the liability for
    earlier separation leading to more severe bleeding attacks, and liability to preterm
    termination of pregnancy.

•   N.B.: PP marginalis posterior is more dangerous than marginalis anterior because:
•   It encroaches on the true conjugate delaying engagement of the head.
•   Engagement of the head will compress the intact part of the placenta against the
    sacrum causing fetal asphyxia while leaving the lower separated part of placenta
    uncompressed leading to uncontrolled bleeding.

• Advancing maternal age (>35 years).
• Multiparity (para five or greater).
• Prior caesarian delivery: the incidence
    increases with the number of previous C.S.
•   Multifetal pregnancy: the incidence reaches up
    to 40% in twin pregnancy.
•   Other causes of large placentae: as placenta
    membranacaea or multiple lobes (as bipartite).

• During the 2nd half of pregnancy the
 lower uterine segment is progressively
 passively and painlessly stretching and
 elongating but the inelastic placenta
 cannot stretch in a similar pattern, so
 inevitable separation occurs (shearing
 effect) leading to unavoidable bleeding.

• The lower uterine segment: It is thin,
     vascular, and friable thus more liable to
•    The placenta:
    –   Extends to the lower uterine segment, may reach or
        cover the internal os.
    –   Higher incidence of placenta accreta, due to poor
        decidual reaction in the lower segment.
•     The umbilical cord: there is higher
     incidence of velamentous insertion and vasa

• Clinical Symptoms of APH due to PP:
• Vaginal bleeding in placenta praevia is
   characterized by being:
       – Causeless (unless it follows intercourse or vaginal
       – Painless (unless it is associated with labour pains)
       – Recurrent (unless pregnancy is terminated with the first
       – Bleeding is always revealed and bright red in colour.
Clinical Signs in APH due to PP:
• General signs related to bleeding:
  –    The general condition is proportionate to amount of
  –    Anaemia is present if bleeding is severe or
  –    No signs of toxaemia of pregnancy as in some cases
       of placental abruption (see later).
  –    Signs of hypovolaemic shock, if present, include:
  –    Drowsiness, delirium or loss of consciousness.
  –    Pallor, tachypnia, hypotension, and tachycardia
       (rapid and rising pulse).
      • N.B.: In APH due to PP, signs of hypovolaemic shock
         correlate with the severity of bleeding (amount of blood
         lost), the rate of blood loss (duration of bleeding), and the
         previous general condition of the patient (haemoglobin
         level and anaemia).
Abdominal Examination in PP:
• The abdomen and uterus are lax and not
    tender, so fetal parts and movements are
    easily felt.
•   Fundal level corresponds to the period of
•   Malpresentations are common, and there is
    usually delayed engagement of the presenting
    part in the last weeks of pregnancy.
•   Fetal heart sounds (FHS) are usually audible
    and regular, except if severe bleeding
    compromises the fetal condition.
Pelvic vaginal Examination:
•       Vaginal examination (PV) in PP is generally
        contra-indicated, as it may provoke an
        uncontrollable attack of bleeding due to placental
    –     Indications of PV examination: Only when active
          management is decided.
    –     Aim of PV examination: To obtain the following data:
•       The degree of cervical effacement and dilatation, and
        the condition of the membranes.
•       The type and station of the presenting part and
        assessment of pelvic adequacy.
•       The degree of PP if present (placenta is felt as tough
        spongy mass by the index finger while a blood clot is
Precautions during vaginal examination if
• It should NOT be done at home or even in
  hospital outpatient or emergency room.
• It should be done ONLY in the operating
  theater under complete aseptic
• Anaesthesia should be ready and blood
  transfusion is readily available
• The settings for performing an immediate
  caesarean section are prepared
Ultrasound diagnosis of PP:
•   Ultrasonography (US) is the gold standard in the
    diagnosis of placenta praeviae (PP). Placental
    localization can be easily made by US at the middle of
    the second trimester. By beginning of the third
    trimester partial and complete types of PP can be
    easily excluded during any attack of vaginal bleeding.
•   US, is also the gold standard in the differentiation
    between APH due to PP from that due to placental
•   Other additional US benefits include accurate
    estimation of fetal gestational age, amniotic fluid
    volume evaluation, assessment of fetal well being, and
    exclusion of major fetal anomalies.
• Laboratory Investigations:
  – Complete blood picture (CBC), to detect
    anaemia necessitating blood transfusion.
  – Urine analysis: to exclude albuminuria
    associated with preeclampsia (PE).

 due to PP:
    • Other causes of APH (placental abruption, vasa
      praevia, and local gynecologic causes).
    • Other causes of bleeding as severe hypertension
      and thrombocytopenic purpura, etc...
• Factors affecting the management of APH
 secondary to PP:
  – The severity of bleeding and its effect on the patient's
    general condition.
  – The duration of gestational age and its effect on fetal
    lung maturity.
• The main lines of management in Placenta
 Praevia are:
  – Expectant (conservative) Management (continuation
    of pregnancy)
  – Active management (termination of pregnancy)
          Expectant Management
• The aim of conservative (expectant)
  management is to allow pregnancy to continue
  until either fetal maturity is achieved, or labor
  pains start spontaneously.
• Indications of expectant management:
   – Pregnancy < 37 weeks, with mild bleeding and
     absent labour pains.
   – Patient is in good general condition
   – Fetus is living and with no associated gross fetal
      Lines of expectant management:

• Complete bed rest, diet and vitamin support.
• Correction of anaemia, if present, by oral or
    parentral iron therapy.
•   Localization of the placenta by US, to exclude
    placental abruption.
•   Laboratory investigations to check on the
    bleeding and coagulation profiles.
•   After complete cessation of bleeding, a local
    gynaecologic examination could be performed
    (speculum examination) to exclude local organic
• The aim of active management is the immediate
  termination of pregnancy whenever the fetus is mature
  or the bleeding is so severe compromising maternal and
  fetal health.

• Indications of active management:
   – Any bleeding > 37 weeks gestation (even if mild or moderate).
   – Any severe bleeding irrespective of gestation age.
   – Patient with hypovolaemic shock or in poor general condition
   – Labour pains have already started.
   – Recurrent and persistent mild to moderate bleeding during
     expectant management.
   – Fetus is dead or with major fetal anomalies incompatible with
              Caesarean Section:
• Indications specific to Placenta praevia:
  – Total (complete), or partial (incomplete), or marginal
    posterior types of PP.
  – Severe bleeding or patient in shock.
  – Moderate bleeding and cervix is closed.
  – Continuous bleeding during trial for vaginal delivery.
  – Fetal distress due to severe bleeding during
    pregnancy or during labour.
• Other indications associated with PP:
  – Elderly primigravida, previous caesarean section,
    associated malpresentations, any degree of pelvic
    contraction, associated pregnancy complications as
    toxaemia or diabetes.
Precautions during performing C.S. for
Placenta praevia:
• Anti-shock measurements including blood transfusion if needed.
• The technique is by a lower segment C.S.
• After performing the uterine incision the fetus is delivered before
  the placenta.
• IV Oxytocin (syntocinon), ergometrin (methergin), prostaglandins,
  or mesoprostol (cytotec), can be used single or in combination to
  assure excellent uterine contractions capable of controlling expected
  postpartum haemorrhage.
• In cases of uncontrollable bleeding with failure of above measures,
  we may do:
   – Bilateral ligation of the uterine arteries.
   – Unilateral or bilateral ligation of the anterior division of internal
      iliac artery.
   – Abdominal hysterectomy if above measures fail (or in grand
   Trial of vaginal delivery:
• Indications:
  – Absence of any of the previously discussed indications
    for caesarean section.
  – PP lateralis or marginalis anterior, with minimal
    separation and bleeding.
  – Normal fetal well being (no fetal distress, no IUGR).
  – Fetus is in a cephalic presentation (best
    occipitoanterior position).
  – Favorable local pelvic examination (cervix is ripe,
    sufficiently dilated, pelvis adequate and head not in a
    high station)
Method: Should be done in the following

• Artificial rupture of membranes (ROM) :
    – Stops the shearing effect and separation of the
      placenta from lower segemnt
    – Allows more rapid descent of the head and
      compression of the bleeding sinuses.
    – Stimulates uterine contractions (prostaglandin
• Intravenous oxytocin (unless
    contraindicated), in order to augment uterine
•   Care of the 3rd stage and puerperium to
    avoid postpartum haemorrhage and treat
          Complications and effects of PP on
          pregnancy, labour and puerperium:
•       Unavoidable haemorrhage causing hypovolaemic shock if severe
        and anaemia if mild and recurrent.
•       Abortion, IUGR and IUFD (intrauterine fetal death).
•       Premature delivery (with all complications of prematurity).
•       Malpresentations and non-engagement of the presenting part
        (dysfunctional labour).
•       Predisposition to presentation and prolapse of cord.
•       Postpartum haemorrhage due to:
    –      Defective retraction in the lower uterine segment so unable to close
           the bleeding sinuses.
    –      Inertia of the upper uterine segment due to anaemia.
    –      Retention of parts of the placenta due to abnormal adhesion to lower
           uterine segment.
    –      Lower uterine segment is thin and vascular so liable to be torn during
           any manipulation.
•       Puerperal sepsis (due to anaemia and laceration).

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