Miscarriage Flashcards
Definition
Involuntary loss of pregnancy before 24 weeks of gestation. It can be classified as either early (<12 weeks) or late (13-24 weeks)
Aetiology
Embryonic factors
Maternal factors
Embryonic factors
Embryonic factors: Most miscarriages in first trimester
- Chromosomal abnormality (80%)
- Embryonic malformation: e.g. CNS defect
Maternal factors
- 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.
Classification of miscarriages
- Threatened
- Inevitable
- Incomplete
- Complete
- Missed (silent)
- Recurrent
Threatened
Vaginal bleeding with a closed cervix and a fetus that is alive
Inevitable
Vaginal bleeding with an open cervix
Incomplete
Retained products of conception remain in the uterus after the miscarriage. Pregnancy will not continue
Complete
A full miscarriage has occurred, and there are no products of conception left in the uterus
Missed (silent)
The fetus is no longer alive, but no symptoms have occurred.
Non viable pregnancy seen on USS as an incidental finding.
Recurrent
≥ 3 consecutive miscarriages before 24 weeks of gestation
Anembryonic pregnancy
a gestational sac is present but contains no embryo
Epidemiology
- 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
Signs
- Structural abnormalities: fibroids, polyps and adhesions
- Cervical os status: open or closed
- Haemodynamic instability: if there is significant bleeding (uncommon)
Symptoms
- 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
Diagnosis
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
Threatened miscarriage treatment
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
Incomplete or complete miscarriage in 1st trimester management
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
Medical management
- 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
How does Misoprostol work?
- 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
Surgical management
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.
When should medical or surgical interventions be offered?
- Increased bleeding risk (e.g. late first trimester pregnancy or coagulopathy)
- Previous traumatic experience in pregnancy (e.g. stillbirth, miscarriage)
- Evidence of infection
