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MAJOR CAUSES OF ANTEPARTUM HAEMORRHAGE

Blood loss is one of the commonest occurrences during the period in which a woman carries a pregnancy. Even before pregnancy, bleeding from the vagina during menstruation is synonymous to all women of childbearing age. This bleeding from the genital tract especially during pregnancy can appear at anytime in the pregnancy from the onset, right to when the woman delivers her baby and even afterwards. Depending on the cause and time the bleeding occurs in pregnancy, it suggests to the healthcare givers what exactly they are dealing with and how to tackle the issue in order to achieve the best possible care for both mother and fetus.

Antepartum haemorrhage (APH) refers to any bleeding from the genital tract at 28 weeks or more during pregnancy. Bleeding in APH may be associated with abdominal pains or occur painlessly. Antepartum haemorrhage is an obstetric emergency regardless whether the woman has pain or not and medical attention should be sought immediately as if left untreated, can lead to death of the mother and/or the fetus. Blood loss from the genital tract before the 28th week of pregnancy is not considered as antepartum haemorrhage, and that is what differentiates APH from other forms of bleeding in pregnancy.

General causes of Antepartum haemorrhage 

The possible causes of antepartum haemorrhage can come from either the mother or the fetus. Maternal causes can either be physiological or pathological but fetal causes are always pathological. The general causes of APH are

  • Placental abnormalities including placenta praevia, placental abruption, and vasa praevia.
  • Maternal blood loss from “bloody show” which is a normal physiological occurrence during labour.
  • Uterine rupture before delivery.
  • Bleeding from the lower genital tract involving the cervix (cervicitis, cervical neoplasm, cervical polyp) and bleeding from the vagina itself due to trauma or neoplasm, is a maternal cause of antepartum haemorrhage.
  • Bleeding from other sources outside the genital tract such as urinary tract bleeding from urinary tract infection and G. I bleeding from haemorrhoids, inflammatory bowel disease e.t.c can occur at the defined period of antepartum haemorrhage.

Bloody show is the most common physiological maternal cause of antepartum haemorrhage. The most common causes of antepartum haemorrhage are from placental abnormalities. Each type of placental abnormality presents differently with different risk factors and are diagnosed and managed differently.

PLACENTA PRAEVIA 

placenta praevia is the second most common cause of antepartum haemorrhage next after placenta abruption, which is the most common cause. Placenta praevia occurs when the placenta grows at the lower part of the uterus and located near to or actually covering the cervix. Placenta praevia is more simple and commonly referred to as low lying placenta and is classified into four depending on the proximity of the placenta to the cervix.

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  1. Type 1 : placenta is located at the lower part of the uterus but does not come near the cervix. Vaginal delivery is possible in this type of placenta praevia.
  2. Type 2 : the placenta is at the lower part of the uterus and touches but does not cover the cervix. It is also called marginal placenta praevia.
  3. Type 3 : also called partial placenta praevia where the placenta located at the lower part of the uterus and partially covers the cervix.
  4. Type 4 : also called complete placenta praevia in which the low lying placenta completely covers the cervix.

Types 2, 3 and 4 are associated with heavy bleeding during labour as the cervix dilates making vaginal delivery very risky.

Bleeding from the genital tract is the symptom for placenta praevia. The blood is usually bright red in colour and is often painless.

What causes placenta praevia? 

The cause of placenta praevia is unknown but certain risk factors have been found that predispose to the occurrence of placenta praevia. They include

  • Women who have had previous cesarean section or uterine surgery.
  • Women who have had placenta praevia in past pregnancy.
  • Age > 35 years
  • Multiple pregnancy or have had multiple pregnancy in the past.
  • Closely spaced consecutive pregnancies.
  • Smoking.
  • Fetal abnormalities.

Diagnosis and management of placenta praevia 

The diagnosis of placenta praevia, in addition to the clinical features, is confirmed through repeated ultrasound scans. An ultrasound scan done at 18 weeks to 20 weeks can show a low lying placenta. A repeat scan at 32 weeks or 36 weeks is required to confirm the position of the placenta before the onset of labour.

The management of placenta praevia is delivery of the baby through a cesarean section due to the great bleeding risk attempted vaginal delivery has especially for placenta touching or covering the cervix.

PLACENTA ABRUPTION 

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Placenta abruption occurs when part of a normal positioned placenta separates from the wall of the uterus before a term delivery.  A large amount of vaginal blood loss usually occurs in placenta abruption which can lead to maternal and fetal mortality. Some of the blood may also remain in the uterus leading to a blood clot formed behind the placenta and making estimation of blood loss inaccurate.

The signs and symptoms of placenta abruption involves bleeding from the genital tract with associated abdominal pain and sometimes back ache. The blood loss from placenta abruption is usually dark red in colour. The uterus may be tender when palpated and fetal parts may be impalpable due to tensed uterus.

Causes and risk factors of placenta abruption 

The precise cause is not known but predisposing factors include

  • Woman with chronic hypertension or pre-eclampsia.
  • Woman who has had a previous placenta abruption.
  • Smoking and cocaine use.
  • Chorioamnionitis.
  • Sudden reduction in size of an overdistended uterus e.g  rupture of membranes in polyhydramnios or multiple pregnancy.
  • Trauma, whether physical or motor vehicle accident.

Management of placenta abruption 

Admission to hospital is required for any woman with placenta abruption. Ultrasound scan is done and cardiotocography for the fetal heart beat is done also.

If there is significant blood loss, it is quickly compensated by intravenous fluids or blood transfusion as the case may be.

The ultimate treatment for placenta abruption is the delivery of the baby after the assessment of the healthcare team on the best route of delivery.

VASA PRAEVIA 

This is a very rare condition and is the least common cause of antepartum haemorrhage. It occurs where umbilical cord blood vessels traverse the fetal membranes of the lower uterine segment unsupported by the umbilical cord or the placenta. This results in bleeding from the fetal blood vessels when fetal membrane ruptures. This is the only antepartum haemorrhage where the blood loss is from the fetus and not the mother.

Placenta praevia is a single risk factor for vasa praevia. When vasa praevia occurs, delivery of the fetus is very imminent.

COMPLICATIONS OF ANTEPARTUM HAEMORRHAGE 

  • Maternal anaemia
  • Fetal anaemia
  • Preterm delivery
  • Intrauterine Growth Retardation
  • Premature rupture of membrane
  • Abnormal carditocograph of fetus
  • Shock and maternal and/or fetal mortality.

 

 

REFEEENCE

Wikipedia : “Antepartum bleeding”

brochures.master.org : “Antepartum haemorrhage”

3centres.com : “Antepartum haemorrhage (APH), including placenta praevia, abruption and vasa praevia”

 

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