Miscarriage

Question 1

Definition

Answer 1

Involuntary loss of pregnancy before 24 weeks of gestation. It can be classified as either early (<12 weeks) or late (13-24 weeks)

Question 2

Aetiology

Answer 2

Embryonic factors
Maternal factors

Question 3

Embryonic factors

Answer 3

Embryonic factors: Most miscarriages in first trimester
- Chromosomal abnormality (80%)
- Embryonic malformation: e.g. CNS defect

Question 4

Maternal factors

Answer 4

• Infection: e.g. ascending infection from the lower genital tract
• Maternal anatomical anomalies: fibroids, septa, adhesions or polyps may impede the natural development of a foetus.
• Exposure to teratogens
• Thrombophilia: antiphospholipid syndrome usually causes recurrent early mischarriages (first or second trimester)
• Endocrine: poorly controlled diabetes mellitus or thyroid disease.

Question 5

Classification of miscarriages

Answer 5

• Threatened
• Inevitable
• Incomplete
• Complete
• Missed (silent)
• Recurrent

Question 6

Threatened

Answer 6

Vaginal bleeding with a closed cervix and a fetus that is alive

Question 7

Inevitable

Answer 7

Vaginal bleeding with an open cervix

Question 8

Incomplete

Answer 8

Retained products of conception remain in the uterus after the miscarriage. Pregnancy will not continue

Question 9

Complete

Answer 9

A full miscarriage has occurred, and there are no products of conception left in the uterus

Question 10

Missed (silent)

Answer 10

The fetus is no longer alive, but no symptoms have occurred.
Non viable pregnancy seen on USS as an incidental finding.

Question 11

Recurrent

Answer 11

≥ 3 consecutive miscarriages before 24 weeks of gestation

Question 12

Anembryonic pregnancy

Answer 12

a gestational sac is present but contains no embryo

Question 13

Epidemiology

Answer 13

• Advanced maternal age > 35 years (esp foetal chromosomal abnormalities)
• Advancing paternal age: > 45 years of age
• Previous miscarriage: the risk is significantly greater after 3 consecutive miscarriages
• Lifestyle: smoking, alcohol, drugs
• Previous gynaecological surgery
• Connective tissue disorders: SLE
• Systemic disease: uncontrolled DM and thyroid disease
• TORCH infections

Question 14

Signs

Answer 14

• Structural abnormalities: fibroids, polyps and adhesions
• Cervical os status: open or closed
• Haemodynamic instability: if there is significant bleeding (uncommon)

Question 15

Symptoms

Answer 15

• Vaginal bleeding: presence or absence of clots
• Lower abdominal pain: reflects the process of expelling the foetus
• Symptoms of anaemia: if there is significant bleeding: dizziness and pallor

Question 16

Diagnosis

Answer 16

Urine hCG: confirm pregnancy (falling indicates failing pregnancy)
GOLD STANDARD: Transvaginal USS = three key features on
- Mean gestational sac diamete: when visible pregnancy is considered viable.
- Fetal pole and crown-rump length
- Fetal heartbeat

Question 17

Threatened miscarriage treatment

Answer 17

Vaginal progesterone 400 mg twice daily : offer to women with an intrauterine pregnancy confirmed by a scan, if they have vaginal bleeding and have previously had a miscarriage
- If a fetal heartbeat is confirmed, continue progesterone until 16 completed weeks of pregnancy

Question 18

Incomplete or complete miscarriage in 1st trimester management

Answer 18

FIRST LINE: advice and analgesia
- If symptoms improve: repeat a urine pregnancy test in 3 weeks
- If symptoms do not improve : repeat TVUS and consider medical or surgical management
- If symptoms continue beyond 14 days, this is failure of expectant management

Question 19

Medical management

Answer 19

• Offered if expectant management fails. Given to ‘expedite the miscarriage’
  = Vaginal or oral misoprostol and repeat a pregnancy test in 3 weeks
  = Oxytocin or Ergometrine = to stem bleeding

Question 20

How does Misoprostol work?

Answer 20

• Prostaglandin analogue that causes myometrial contractions, resulting in expulsion of foetal tissue
• Bleeding should start within 24 hours and patients should contact their doctor if it has not
• Analgesia and antiemetics should be co-prescribed

Question 21

Surgical management

Answer 21

If expectant or medical management fails with products still retained in utero:
- Manual vacuum aspiration: under local anaesthetic or
- Surgical management : under general anaesthetic; causes rapid symptom resolution
- Anti-D rhesus prophylaxis: offer to all rhesus-negative women who are undergoing surgical management for miscarriage.

Question 22

When should medical or surgical interventions be offered?

Answer 22

• Increased bleeding risk (e.g. late first trimester pregnancy or coagulopathy)
• Previous traumatic experience in pregnancy (e.g. stillbirth, miscarriage)
• Evidence of infection