Placental abruption Premature separation of a normally situated placenta occurring aher the 24th week of pregnancy is referred to as a placental abruption. The aetiology of this type of haemorrhage is not always clear, but it may be associated with: hypertension a sudden reduction in uterine size, for instance when the membranes rupture or after the birth of a first twin

trauma, for instance external cephalic version of a fetus presenting by the breech, a road traffic accident or domestic violence, as these may partially dislodge the placenta high parity -previous caesarean section cigarette smoking.

Incidence Placental abruption occurs in 0.49–1.8% of all pregnancies with 30% of cases being classed as concealed and 70% being revealed although there is probably a combination of both in many situations (mixed haemorrhage). In any of these situations the blood loss may be mild, moderate or severe, ranging from a few spots to continually soaking clothes and bed linen.

I n revealed haemorrhage, as blood escapes from the placental site it separates the membranes from the uterine wall and drains through the vagina. However in concealed haemorrhage blood is retained behind the placenta where it is forced back into the myometrium, infiltrating the space between the muscle fibres of the uterus. This extravasation (seepage outside the normal vascular channels) can cause marked damage and, if observed at operation, the uterus will appear bruised,

oedematous and enlarged oedematous and enlarged. This is termed Couvelaire uterus or uterine apoplexy. In a completely concealed abruption with no vaginal bleeding, the woman will have all the signs and symptoms of hypovolaemic shock and if the blood loss is moderate or severe she will experience extreme pain. In practice the midwife cannot rely on visible blood loss as a guide to the severity of the haemorrhage; on the contrary, the most severe haemorrhage is ohen that which is totally concealed. As with placenta praevia, the maternal and fetal condition will dictate the management

Mild separation of the placenta Most commonly a woman self-admits to the maternity unit with slight vaginal bleeding. On examination the woman and fetus are in a stable condition and there is no indication of shock. The fetus is alive with normal heart sounds. The consistency of the uterus is normal and there is no tenderness on palpation. The management would include the following plan of care: An ultrasound scan can determine the placental localization and identify any degree of concealed bleeding The fetal condition should be assessed by frequent or continuous monitoring of the fetal heart rate while bleeding persists. Subsequently a cardiotocograph (CTG) should be undertaken once or twice daily

If the woman is not in labour and the gestation is less than 37 weeks she may be cared for in the antenatal ward for a few days. She may return home if there is no further bleeding and the placenta has been found to be in the upper uterine segment. The woman should be encouraged to return to hospital if there is any further bleeding. Women who have passed the 37th week of pregnancy may be offered induction of labour, especially if there has been more than one episode of mild bleeding Further heavy bleeding or evidence of fetal compromise could indicate that a caesarean section is necessary.

The midwife should offer the woman comfort and encouragement by afending to her emotional needs, including her need for information. Physical domestic abuse should be considered by the midwife, which the woman may be frightened to reveal. It should also be noted that if the woman is already severely anaemic then even an apparently mild abruption may compromise her wellbeing and that of the fetus.

Moderate separation of the placenta About a quarter of the placenta will have separated and a considerable amount of blood may be lost, although concealed haemorrhage must also be considered. The woman will be shocked and in pain, with uterine tenderness and abdominal guarding. The fetus may be alive, although hypoxic, however intrauterine death is also a possibility. The priority is to reduce shock and to replace blood loss: Fluid replacement should be monitored with the aid of a central venous pressure (CVP) line. Meticulous fluid balance records must be maintained. The fetal condition should be continuously assessed by CTG if the fetus is alive, in which case immediate caesarean section would be indicated once the woman's condition is stabilized.

If the fetus is in good condition or has died, vaginal birth may be considered as this enables the uterus to contract and control the bleeding. The spontaneous onset of labour frequently accompanies moderately severe placental abruption, but if it does not then amniotomy is usually sufficient to induce labour. Oxytocics may be used with great care, if necessary. The birth of the baby is often quite sudden after a short labour. The use of drugs to attempt to stop labour is usually inappropriate.

Severe separation of the placenta This is an acute obstetric emergency where at least two-thirds of the placenta has detached and 2000 ml of blood or more are lost from the circulation. Most or all of the blood may be concealed behind the placenta. The woman will be severely shocked, perhaps far beyond the degree to which would be expected from the visible blood loss ,The blood pressure will be lowered but if the haemorrhage accompanies pre-eclampsia the reading may lie within the normal range owing to a preceding hypertension. The fetus will almost certainly be dead. The woman will have very severe abdominal pain with excruciating tenderness and the uterus would have a board-like consistency.

Features associated with severe antepartum haemorrhage are: coagulation defects renal failure pituitary failure postpartum haemorrhage. Treatment is the same as for moderate haemorrhage: Whole blood should be transfused rapidly and subsequent amounts calculated in accordance with the woman's CVP.

Labour may begin spontaneously in advance of amniotomy and the midwife should be alert for signs of uterine contraction causing periodic intensifying of the abdominal pain. If bleeding continues or a compromised fetal heart rate is present, caesarean section will be required as soon as the woman's condition has been adequately stabilized.