The passage from the safety of the uterus to the outside world is made hazardous by the following:
- The skull has to mould to facilitate passage through the pelvis and there may be cephalopelvic disproportion (CPD) - a mismatch between the size of the fetal head and the capacity of the maternal pelvis. It may represent a large head in a normal pelvis or a normal head in a restricted pelvis.
- Malposition increases risk, whilst malpresentation necessitates Caesarean section.
- Contractions tax the reserve of the placenta.
- The lungs and circulation undergo great changes.
Difficulties in delivery may compound the situation. Delivery may need to be expedited because of fetal distress. This may present as fetal hypoxia (shown on electronic fetal monitoring) and as acidosis on fetal blood sampling.
Injuries may be caused by a combination of mechanical trauma and hypoxia. Birth injuries may be minor and transient but they can produce serious and permanent effect as well as being fatal. Previously it was assumed that most cases of cerebral palsy were due to obstetric mismanagement, but now the figure for those caused by obstetric trauma is put at around 5%.
Figures for major (but not fatal) birth trauma in the UK are not routinely collected. For fatal outcomes a national intrapartum-related confidential enquiry reported and reviewed 37 cases in which birthweight was in excess of 2,500 grams for the year 1994-1995.
American and Canadian papers found that birth trauma occurred in 2% deliveries and brachial plexus injury in 0.5 to 2.0 per 1,000 live births.
Risk factors for birth trauma include:
- A large infant (especially if weighing more than 4,500 g).
- Cephalopelvic disproportion (CPD).
- Instrumental delivery (especially mid-cavity forceps or ventouse delivery for deep transverse arrest).
- Breech delivery (advantages of elective lower segment Caesarean section (LSCS) for breech presentation are not clear).
- A premature baby (small head and incompletely formed skull - precipitate delivery can cause "champagne cork popping" - risking intracranial haemorrhage).
- Shoulder dystocia (a skilled midwife or obstetrician will reduce the risk).
Other risk factors include:
- Primagravida (untried pelvis).
- Very short labour may represent precipitate delivery of a premature baby.
- Very long labour may indicate CPD
- Congenital abnormalities (especially if there is enlarged head or macrosomia).
- Bleeding between the periosteum and skull causes a haematoma, usually in the parietal region and sometimes the occipital region. Spread is restricted by suture lines that are adherent.
- Blood loss can cause anaemia and even hypotension.
- As the haematoma resolves, breakdown of haemoglobin can cause hyperbilirubinaemia that may need treatment.
- An underlying skull fracture is found in up to 20% cases. If it is thought to be depressed, CT or MRI imaging is required.
- Spontaneous remission may take weeks and there is sometimes residual calcification.
- A haematoma may rarely become infected.
- Consider the possibility of a coagulation defect.
- Bleeding between the periosteum and scalp is usually associated with use of ventouse extraction.
- 77% follow instrumental delivery and 40-50% overlie a skull fracture or brain haemorrhage.
- It usually appears within 12-72 hours of birth as a soft, fluctuant mass within the scalp, especially over the back of the head.
- It can spread slowly and be unnoticed and present as hypotension.
- The spread is not restricted by suture lines.
- As with cephalohaematoma, management is conservative but check for anaemia.
- This is a poorly defined, subcutaneous collection of serosanguinous fluid that spreads over suture lines and the midline.
- It is very common after prolonged labour.
- It does not cause significant problems and needs only to be monitored.
Cuts and abrasions
- These may result from operative delivery, including cutting the baby with the scalpel blade at LSCS. Great care is needed in cutting the last layer of the uterus, even in an emergency.
- Cuts need closing and dressing. Topical antibiotic may be indicated.
Subcutaneous fat necrosis
- This is not usually apparent at birth.
- Some time later, irregular, hard, subcutaneous plaques appear with overlying dusky red-purple discoloration.
- They occur on the extremities, face, trunk or buttocks, having been caused by pressure during delivery.
- There is no treatment and they should resolve but sometimes there is calcification.
Brachial plexus injury
The majority of these are Erb's palsy involving the upper part of the brachial plexus. The underlying problem is usually injudicious traction when the anterior shoulder is trapped (shoulder dystocia). Only 10% involve the whole brachial plexus. Associated injuries include:
- Fractured clavicle.
- Fractured humerus.
- Subluxation of cervical spine.
- Cervical cord injury.
- Facial palsy.
- Occasionally, phrenic nerve paresis.
- There is damage to the C5, C6 segments of the brachial plexus.
- It produces loss of motion of the shoulder with a limp arm, adducted and internally rotated. The elbow is pronated and extended with wrist flexed.
- The grasp reflex is normally maintained but Moro, biceps and radial reflexes are lost.
The position of the hand is said to be reminiscent of a porter who is turning away but is holding out his hand behind him for a tip.
This is much less common that Erb's palsy in infants.
- It is due to damage of the nerves of segmental origin C7, C8, T1 in the brachial plexus.
- It causes paralysis with weakness of the hand and loss of grasp reflex.
- Horner's syndrome may be seen if there is T1 damage.
- Most cases of brachial plexus injury resolve spontaneously within four months, but it can take up to two years.
- X-rays to exclude fractures and examination for phrenic nerve paresis are required. Further investigations include MRI scan, electromyography, nerve conduction studies and CT myography.
- To prevent contractures, immobilise the arm across the upper abdomen for seven days, then start physiotherapy using wrist splints.
- Consider surgery if movement is not returning after three months and electrophysiology results suggest a poor prognosis.
Cranial nerve injury
Cranial nerve and spinal cord injuries result from hyperextension, traction and overstretching with simultaneous rotation. Neurapraxia will resolve swiftly but complete nerve or cord transection is a much more serious matter.
- Central damage to the facial and vagus nerves causes an asymmetrical face on crying, with swelling and smoothness of the affected side and drooping of the side of the mouth.
- Peripheral damage causes paralysis to the eye, forehead or mouth only.
- Most cases soon start to recover but full recovery may take months.
- The eye must be protected with a covering and synthetic tears.
- If there is no improvement after 7-10 days, investigation is required.
- Phrenic nerve damage can cause paralysis of half of the diaphragm, leading to breathing difficulties with significant mortality. Ultrasound or X-ray shows an elevated hemidiaphragm but this may be absent in the early stages. Screening may show immobility.
Laryngeal nerve injury
- Unilateral paralysis often presents with a hoarse cry or stridor and may affect swallowing.
- Bilateral damage causes severe respiratory problems.
- Diagnosis is by laryngoscopy to exclude other causes of the symptoms.
- Recovery usually occurs after 4-6 weeks but can take up to a year.
Spinal cord injury
- Damage to the spinal cord often results in stillbirth or babies who die soon after delivery due to an inability to breathe.
- Ventilation may be life-saving but, if the lesion is not a temporary neuropraxia, there will be later agonising decisions about turning off the ventilator.
- Those who survive are weak and often develop spasticity.
- Diagnosis is by MRI or CT myelography.
- Treatment is supportive.
- Fractured clavicle is common and presents with apparent paralysis.
- Palpation may show crepitus, uneven bone and muscle spasm.
- It heals within 7-10 days with the arm immobilised.
- Confirm the diagnosis by X-ray.
- Look for other damage.
Arm and leg bones
- Fracture may be heard during delivery.
- It presents with absence of normal movement of the limb, with swelling becoming apparent later.
- Confirm with X-ray.
- Treat with 8-10 days of splinting or reduction and casting if displaced.
- Check for radial nerve damage in arm fractures.
- This presents with shock, pallor and a distended abdomen, possibly bluish in colour.
- Check for anaemia.
- Diagnose with paracentesis.
- Causes include hepatic laceration and rupture of spleen, so this is serious.
Factors within labour are complex, but processes such as uteroplacental vascular disease, reduced uterine perfusion, fetal sepsis, reduced fetal reserves and cord compression can be involved alone or in combination producing fetal distress. Gestational and antepartum factors modify the fetal response to them.
Even though cerebral palsy is strongly associated with a low Apgar score 5 minutes after birth, the majority of babies with low scores DO NOT develop cerebral palsy. The majority of cases are now thought to be a consequence of postpartum insults to the fetus.
Good maternity care will reduce the risk of an adverse outcome to both mother and child.
Fear of fetal damage and the vast cost of litigation have led to an increasing rate of Caesarean section that is now around 24% in the UK as a whole with significant geographical variation. In some parts of the world the figure is higher.
There is debate as to whether the current rising rate of Caesarean section has gone too high. The World Health Organization has suggested that, in developed countries, the figure should not be above 15%. Skills in the use of Kielland's forceps and assisted breech delivery are being lost as LSCS is more readily undertaken.
A major contributor to perinatal mortality and morbidity is prematurity. Prevention of this is important and analysis of figures for outcomes should exclude babies below a certain weight.
Weight is a more reliable parameter for risk assessment than gestational age.
Further reading & references
- Brown HC, Paranjothy S, Dowswell T, et al; Package of care for active management in labour for reducing caesarean section rates in low-risk women. Cochrane Database Syst Rev. 2008 Oct 8;(4):CD004907.
- Naftalin J, Paterson-Brown S; A pilot study exploring the impact of maternal age and raised body mass index on caesarean section rates. J Obstet Gynaecol. 2008 May;28(4):394-7.
- CEMACH Perinatal Mortality 2007, published June 2009 (5th annual report)
- Jan MM; Cerebral palsy: comprehensive review and update. Ann Saudi Med. 2006 Mar-Apr;26(2):123-32.
- O'Mahony F, Settatree R, Platt C, et al; O'Mahony F, Settatree R, Platt C, et al; Review of singleton fetal and neonatal deaths associated with cranial trauma and cephalic delivery during a national intrapartum-related confidential enquiry. BJOG. 2005 May;112(5):619-26.
- Baskett TF, Allen VM, O'Connell CM, et al; Baskett TF, Allen VM, O'Connell CM, et al; Fetal trauma in term pregnancy. Am J Obstet Gynecol. 2007 Nov;197(5):499.e1-7.
- Hankins GD, Clark SM, Munn MB; Cesarean section on request at 39 weeks: impact on shoulder dystocia, fetal trauma, neonatal encephalopathy, and intrauterine fetal demise. Semin Perinatol. 2006 Oct;30(5):276-87.
- Pradhan P, Mohajer M, Deshpande S; Outcome of term breech births: 10-year experience at a district general hospital. BJOG. 2005 Feb;112(2):218-22.
- Crofts JF, Fox R, Ellis D, et al; Observations from 450 shoulder dystocia simulations: lessons for skills training. Obstet Gynecol. 2008 Oct;112(4):906-12.
- Hoffman MK, Bailit JL, Branch DW, et al; A Comparison of Obstetric Maneuvers for the Acute Management of Shoulder Obstet Gynecol. 2011 Jun;117(6):1272-1278.
- Chang HY, Peng CC, Kao HA, et al; Neonatal subgaleal hemorrhage: clinical presentation, treatment, and predictors Pediatr Int. 2007 Dec;49(6):903-7.
- Ouzounian JG, Korst LM, Phelan JP; Permanent Erb palsy: a traction-related injury? Obstet Gynecol. 1997 Jan;89(1):139-41.
- Weizsaecker K, Deaver JE, Cohen WR; Labour characteristics and neonatal Erb's palsy. BJOG. 2007 Aug;114(8):1003-9. Epub 2007 Jun 12.
- Laroia N, Pediatric Cardiac Birth Trauma, Medscape, Mar 2010
- Birch R, Ahad N, Kono H, et al; Repair of obstetric brachial plexus palsy: results in 100 children. J Bone Joint Surg Br. 2005 Aug;87(8):1089-95.
- Lie KK, Groholt EK, Eskild A; Association of cerebral palsy with Apgar score in low and normal birthweight BMJ. 2010 Oct 6;341:c4990. doi: 10.1136/bmj.c4990.
- Bragg F, Cromwell DA, Edozien LC, et al; Variation in rates of caesarean section among English NHS trusts after accounting BMJ. 2010 Oct 6;341:c5065. doi: 10.1136/bmj.c5065.Status: 500 Server Error
- Terzidou V, Bennett P; Maternal risk factors for fetal and neonatal brain damage. Biol Neonate. 2001;79(3-4):157-62.
|Original Author: Dr Hayley Willacy||Current Version: Dr Hayley Willacy||Peer Reviewer: Dr Colin Tidy|
|Last Checked: 19/08/2011||Document ID: 1864 Version: 25||© EMIS|
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