Previous placenta

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I- INTRODUCTION-DEFINITION :

They say that’a placenta is prevalent when’he s’inserts in whole or in part on the lower segment The frequency of the hemorrhagic placenta previa is 0.28% pregnancy

II- ETIOLOGY :

A- AVERAGING PLACENTA ON SEGMENT LOWER :

The placenta overflows on the lower segment to increase the area of’maternal-fetal exchanges due to multiple pregnancies, Advanced maternal age, smoking and drug abuse.

B- LOW implantation PRIMITIVE :

  • uterine abnormalities (uterine malformations, fibroma, adenomyosis…)
  • Assisted reproduction
  • Endometrial weakened by multiparity, endometritis, Caesarean scar, ATCD d’abortion, récidive of PP

III- ANATOMICAL CLASSIFICATION :

There are four stages in the classification MacAfee

  • Stage IV : Total central placenta praevia or : fully covering the’orifice cervical interne
  • Stage III : PP part where only a portion of the neck is covered by the placenta
  • Stage II : Marginal PP that outcrops l’orifice cervical interne
  • Stage I : Lateral PP whose lower edge remains at a distance due to l’orifice cervical interne < 5cm

IV- PATHOLOGICAL ANATOMY :

A- MACROSCOPIE :

The PP is generally more spread out and thinner than normal placenta, it shows a small side of the membranes, at this level of villous degeneration zones (fibrin)

In case of fetal death : the placenta shows a decrease 30% placental weight with hematoma associated with death

B- MICROSCOPY FOR DEATH FETAL :

necrosis decidua, Marginal thrombosis with stromal fibrosis detached placental tongue

V- PATHOPHYSIOLOGY :

  • During pregnancy bleeding occurs during uterine contractions that cause a tugging on the lower edge of the placenta
  • When working : I cervical dilatation causes detachment of the placenta
  • L’origin of bleeding is double maternal and fetal

WE- CLINICAL STUDY :

A- FUNCTIONAL SIGNS :

  • L’haemorrhage : made of red blood, franc, appear spontaneously or at’opportunity for uterine contraction or physical exertion. It is often recurrent.
  • The pain kind of uterine contractions

B- GENERAL SIGNS :

Pallor, rapid pulse, low TA.

C- PHYSICAL SIGNS :

  • Palpation : flexible uterus outside contraction, with high and mobile presentation
  • Auscultation : BCF good or altered
  • Examination under speculum : check the’endo-uterine origin of bleeding
  • Televisions : cervical intra looking placental mattress is formally against indicated

VII- ADDITIONAL TESTS :

A- BIOLOGY :

  • GR HR and NFS
  • Results of the blood erase : TP, fibrinogen, soluble complexes, PDF and D.dimères
  • Search fetal red blood cells by the Kleihauer

B- cardiotocographic REGISTRATION :

  • Highlights uterine contractions with normal fetal heart rate
  • Signs of suffering in case of’maternal shock (fetal tachycardia, restricted or late decelerations oscillations)

C- ULTRASOUND :

For abdominal and vaginal way above : allows the diagnosis of placenta previa and to classify as classified by BESSIS :

  • Placenta praevia Antérieur :

– Type 1 : not exceeding the upper third of the bladder
– Type 2 : between the 1/3 and 2/3 upper bladder
– Type 3 : flush with the collar
– Type 4 : is located at 4cm back of the neck

  • Placenta praevia postérieur :

– Type 1 : is located at 4 cm back of the neck
– Type 2 : flush with the collar
– Type 3 : reached the lower third of the bladder
– Type 4 : exceeds the lower third of the bladder

VIII- EVOLUTION- COMPLICATION :

In the absence of treatment : maternal mortality is 25 for miles case (disorders of the’haemostasis, anemia, endometritis, accident thrombo embolique, renal failure, or pituitary necrosis syndrome SHEEHAN)

Fetal mortality is 90% ; it is linked to prematurity, RCIU, especially heart defects)

When Active Management, l’evolution of the PP marked by :

  • The rebleeding
  • RPM risk with chorioamnionitis or prolapsed cord
  • Premature delivery

IX- CLINICAL FORMS :

  • asymptomatic
  • early form of 1is and 2th trimester
  • Forms associated :

– and HRP
– placenta accreta
– Rupture of’a prævia vessel (vasa praevia)

X- DIAGNOSTIC DIFFERECIEL :

  • Any extra genital bleeding (hemorrhagic cystitis, anal fissure or haemorrhoids)
  • vulval bleeding, vaginal or cervical
  • During the 2th trimester : basal decidual hematoma, late ABRT, or hydatidiform mole
  • During the 3th trimester : decidual or marginal hematoma, uterine rupture, placenta circumvallata, Intra uterine melaena.

XI- TREATMENT :

  • Hospitalization in the presence of’a multidisciplinary team (obstetrician, anesthetist, pediatrician)
  • maternal resuscitation : two wide tracks of’on board, decubitus left lateral, oxygen 6 at 81 / m transfusion d’albumin, PFC, blood group iso iso rhesus
  • Conservative treatment :

– Toccolyse : antagonists to’oxytocin (atosiban*), AINS, (3against mimetic indicated if bleeding PP
– lung maturation of corticosteroids : 12mg of betamethazone at 24h d’interval
– Prevention of’allo HR immunization

  • treatment obstetrical :

– caesarean : if emergency : massive hemorrhage’admission or not responding to treatment, or if the presence of signs of fetal distress

Outside the’emergency if PP covering or pathological presentation

– low life : PP non-overlapping with cephalic presentation, artificial rupture of membranes early is advised with strict monitoring of BCF, natural or placenta, perfusion d’oxytocics maintained in the result of childbirth.

XII- CONCLUSION :

If placenta previa, Perinatal mortality has decreased significantly due to the prolongation of pregnancy, l’cesarean section, Prenatal steroids and neonatal resuscitation

Maternal mortality has decreased significantly due to blood transfusions and’cesarean section.

Course of Dr A. ABSURD – Faculty of Constantine