Miscarriage

The loss of a pregnancy at less than 24 weeks’ gestation

Aetiology

Risk factors

  • Maternal age >30-35 (largely due to an increase in chromosomal abnormalities)
  • Previous miscarriage
  • Obesity
  • Chromosomal abnormalities (maternal or paternal)
  • Smoking, cocaine, alcohol misuse
  • Uterine anomalies
  • Previous uterine surgery
  • Anti-phospholipid syndrome
  • Coagulopathies
  • Infections - CMV, rubella, toxoplasmosis, listeria
  • Severe emotional upsets, stress
  • Iatrogenic loss e.g. after. CVS
  • Uncontrolled diabetes

Pathophysiology

  • Early miscarriages occur in the first trimester (<12-13 weeks) and are more common than late miscarriages, which occur at 13-24 weeks

Types of miscarriage

  • Threatened miscarriage: this is where there are some mild symptoms of bleeding with the foetus retained within the uterus as the cervical os is closed
    • Hence there is the 'threat' of a miscarriage, but it is not certain
    • There may be little or no pain
    • Ultrasound reveals that the foetus is present intrauterine
  • Inevitable miscarriage: there is often heavy bleeding and pain, where the foetus is currently intrauterine but the cervical os is open - it is inevitable that the foetus will be lost
    • Ultrasound reveals that the foetus is present intrauterine
  • Complete miscarriage: there was an intrauterine pregnancy which has now fully miscarried, with all products of conception expelled, and the uterus is now empty
    • The os is usually closed
    • The patient may have been alerted to the miscarriage by pain and bleeding
  • Missed miscarriage: the uterus still contains foetal tissue, but the foetus is no longer alive
    • The miscarriage is 'missed' as often the woman is asymptomatic so does not realise something is wrong
    • The cervical os is closed

Clinical presentation

Symptoms

  • The main presenting symptom of miscarriage is vaginal bleeding
    • Passed products may be brought in
  • 'Period type cramps'

Signs

  • If there is excessive bleeding, this can lead to haemodynamic instability
    • Pallor, tachycardia, tachyopnea, hypotension
  • Abdominal examination - the abdomen may be distended, with localised areas of tenderness
  • Speculum examination - assess the diameter of the cervical os, and observe for any products of conception in cervical canal, or local areas of bleeding
  • Bimanual examination - assess any uterine tenderness and any adnexal masses or collections (consider ectopic pregnancy)

Investigations

Bloods

  • Serum hCG
  • FBC
  • Blood group and rhesus status

Imaging

  • Definitive diagnosis is made via a transvaginal ultrasound scan

Management

Less than 6 weeks gestation

  • Women with a pregnancy less than 6 weeks’ gestation presenting with bleeding can be managed expectantly provided they have no pain and no other complications or risk factors (e.g. previous ectopic)
  • Involves awaiting the miscarriage without investigations or treatment
  • An ultrasound is unlikely to be helpful this early as the pregnancy will be too small to be seen
  • A repeat urine pregnancy test is performed after 7-10 days, and if negative, a miscarriage can be confirmed
  • When bleeding continues, or pain occurs, referral and further investigation is indicated

More than 6 weeks gestation

  • Expectant management (do nothing and await a spontaneous miscarriage)
  • Medical management (misoprostol)
  • Surgical management - manual vacuum aspiration, electric vacuum aspiration
    • Anti-rhesus D prophylaxis is given to rhesus negative women having surgical management of miscarriage

Incomplete miscarriage

  • Retained products create risk of infection - requires medical or surgical management

Complications: cervical shock

  • Cramps, nausea/vomiting, sweating, fainting
  • Resolved if products removed from cervix
  • Resuscitation with IVI uterotonics may be required