A number of complications of the third stage of labour may involve a general surgeon, especially where experienced obstetric help is unavailable.

The placenta may be retained either as a result of a constriction ring in the lower uterus or, more rarely, because of morbid adherence at the site of a previous uterine scar, so-called placenta accreta. Separation may be complete or partial, and the latter is frequently associated with primary postpartum haemorrhage.

This is defined as a vaginal blood loss exceeding 500 ml within 24 h of delivery, but most haemorrhages occur during or immediately after the third stage of labour. Common causes include partial separation of the placenta, uterine atony, and genital tract trauma.

Excessive bleeding after vaginal delivery requires immediate action. The general condition of the patient must be assessed, and ergometrine, 0.5 mg, should be given intravenously, regardless of whether or not the placenta has been expelled. The uterine fundus should then be massaged until it contracts and, if the placenta is retained, a vaginal examination should be performed to assess its site. If placental delivery does not appear to be imminent or if bleeding persists, summon assistance, set up an intravenous infusion and request cross-matched blood. Oxytocin, 10 units IV followed by an intravenous infusion of 50 units in 500 ml of normal saline should also be given to keep the uterus firmly contracted. If the placenta has been delivered and the uterus remains relaxed despite these measures, then it should be compressed firmly between a fist introduced into the anterior fornix of the vagina and a hand placed on the lower abdomen, so-called bimanual compression.

If the placenta has not been delivered and remains within the uterine cavity, arrange for manual removal. This should be performed under general anaesthesia unless there is already an effective epidural in place. Place the patient in the lithotomy position and with the fingers held together insert a hand into the vagina. The other hand is placed over the uterine fundus and used to push the uterus down towards the pelvis. The edge of the placenta should then be identified and the vaginal hand gently introduced into the uterus along the plane of cleavage between the placenta and uterine wall. Ideally the whole placenta should be separated and removed intact, after which a further 0.25 mg ergometrine should be administered intravenously. There is a serious risk of traumatic uterine rupture during this procedure. This usually occurs if the operator uses excessive force when insinuating his hand through the constriction ring, or fails to ‘guard’ the uterine fundus by pushing it down on to the vaginal hand. An inexperienced surgeon may also mistake the lower segment for the uterine cavity and attempt to deliver the whole upper segment, instead of the placenta. Rarely the placenta is morbidly adherent and no true cleavage plane will be identified. As this situation creates a serious risk of uterine perforation and severe haemorrhage, hysterectomy is the safest course of action in a woman who has completed her family. If bleeding is not excessive and only a part of the placenta is retained, then a conservative approach may be adopted, and the placenta left in situ. This, however, creates a significant risk of infection and secondary postpartum haemorrhage, and should only be used when the patient is adamant that she wishes to have further children. Prophylactic antibiotics should be administered after manual removal of the placenta to minimize the risk of infection.

If the uterus is well contracted and bleeding persists after the placenta has been delivered, genital tract trauma must be excluded.

Factors predisposing to genital tract trauma during delivery are inexpert operative delivery, previous surgery, and congenital abnormalities, such as a double cervix or vagina.

These are common during the delivery of the fetal head, but serious injury can usually be avoided by an appropriately timed episiotomy. Labial and clitoral lacerations usually heal without treatment, but should be sutured if they are deep or bleed persistently. A vulval haematoma may form beneath intact skin but, more commonly, develops insidiously deep to an inadequately repaired laceration and may extend to fill the ischiorectal fossa with more than 500 ml of blood. The haematoma should be drained under general anaesthesia and, when possible, all bleeding points should be ligated. Prophylactic antibiotics are advisable and blood transfusion may be necessary.

These are uncommon but should be suspected if bleeding persists despite vulval haemostasis and a well-contracted uterus. Predisposing factors include previous cervical surgery, misapplication of forceps or the vacuum extractor, and traumatic manipulation of a malpresentation. Examination should be performed with the woman under general anaesthesia in the lithotomy position and requires good illumination, large retractors, and skilled assistance. Large vaginal lacerations should be oversewn, taking care to obliterate dead space and avoid damage to the underlying rectum. The cervix should be grasped with large sponge holding forceps and drawn down to facilitate inspection. The apex of all tears must be identified and wide, deep sutures inserted to achieve haemostasis. When sutures are inserted into the lateral vaginal fornices great care must be taken to avoid the ureters.

If the apex of a tear cannot be visualized, or if a broad ligament haematoma has formed, then a laparotomy is required to repair the trauma. If the maternal condition deteriorates due to oligaemic shock, a pelvic haematoma or uterine rupture must be excluded.

Uterine rupture occurs in less than 1 in 5000 labours and is usually due to oxytocic hyperstimulation, operative manipulation, or obstructed labour, especially in women with a pre-existing uterine scar. It may also occur before labour, either as a ‘silent’ event with minimal lower abdominal pain and tenderness, or as a result of seat belt trauma in a motor accident. Uterine rupture in labour is most common in multigravidae, and usually involves the lower segment.

Signs of impending rupture include fetal distress, local pain, and tenderness. These are, however, common in labour and are usually missed. Vaginal bleeding may occur, but concealed intraperitoneal haemorrhage is usually associated with fetal death and rapidly leads to severe oligaemic shock. Severe placental abruption may display similar clinical features and should always be considered, especially if the bleeding is largely concealed.

Whenever possible, experienced anaesthetic and surgical staff should be called to assist as the maternal mortality in this condition is high. As soon as resuscitation has been established, a laparotomy should be performed using a vertical midline incision. The fetus should be removed, if it has not already been delivered, and the site of bleeding identified and arrested. The damage can then be assessed and a decision made whether to repair the rupture or perform a hysterectomy. Hysterectomy is the procedure of choice, but the uterus should be conserved, whenever possible, if the patient is primigravid or desires more children. Optimal haemostasis can be achieved with total hysterectomy, but a subtotal hysterectomy, leaving the cervix, may be necessary if the patient's condition is unstable. Extension of the rupture into the upper vagina or bladder may result in ureteric damage and difficulties with haemostasis. If necessary, urological assistance should be sought, and when an open bladder injury has occurred, continuous drainage should be maintained for 10 to 14 days. Uncontrollable haemorrhage may necessitate ligation of the anterior division of one or both internal iliac arteries. It is rarely necessary to pack the pelvis.

Postoperative care includes careful blood and fluid replacement with the aid of central venous pressure measurements, an indwelling Foley catheter, and regular checks of coagulation status and blood electrolyte concentrations. Prophylactic antibiotics should also be administered.

Uterine inversion may occur spontaneously, but is usually the result of mismanagement of the third stage of labour. Spontaneous inversion is extremely rare, but may be caused by a sustained rise in intra-abdominal pressure, such as vomiting, when the placenta is adherent at the fundus of an atonic uterus. Fundal pressure or sustained traction on the umbilical cord with an adherent fundal placenta and atonic uterus is, however, a much more common cause of uterine inversion.

Initially a dimple develops in the fundus of the uterus and may be palpable by abdominal examination. The fundus subsequently reaches the cervix, and passes through it to present at the introitus. In extreme cases, the uterus, cervix, and vagina invert completely. If the placenta has been delivered, then the rough, plum-coloured surface of the uterus will be visible. With mild degrees of inversion the woman complains of lower abdominal pain, but in more severe forms this is followed rapidly by profound shock. Haemorrhage may be minimal, especially if the placenta remains adherent.

Immediate resuscitation and repositioning of the uterus are vital. Delay results in increasing oedema and this makes replacement much more difficult. The patient should be placed in the lithotomy position under general anaesthesia in an operating theatre, and the placenta, if still attached, should be separated. The fundus should the be grasped and gently but firmly returned through the cervix. If this proves difficult because of a cervical contraction ring, then constant, steady pressure should be maintained, if necessary with the aid of a uterine relaxant, until the uterus slides into place. Alternatively, if the equipment is available, O'Sullivan's ‘hydrostatic’ method can be employed. Sponge forceps are applied to the labia and warm sterile saline is run into the vagina from a height of 1 m above the patient while the introitus is occluded with both hands. This usually corrects the inversion quite dramatically. Rarely, it may be necessary to perform a laparotomy and pull the fundus back through the cervix with large, tissue forceps.

After the inversion has been corrected, oxytocics should be given and an intravenous infusion of oxytocin administered to keep the uterus well contracted. Care must be taken to exclude other trauma, and a urinary catheter should be passed to ensure that the urine is clear. Prophylactic antibiotics should also be given routinely to reduce the risk of infection.

Ratnam SS, Rauff M. Postpartum haemorrhage and abnormalities of the third stage of labour. In: Turnbull AC, Chamberlain GVP, eds. Obstetrics. Edinburgh: Churchill Livingstone, 1989: 867–75.

Hibbard BM. Abnormalities of the third stage of labour and obstetric trauma. Principles of obstetrics. London: Butterworths, 1988: 676–88.