[13] Miscarriage Flashcards
What is a miscarriage?
When there is loss of pregnancy before 24 weeks gestation
What % of recognised pregnancies end in miscarriage?
12-24%
Why is the rate of miscarriage probably higher than we know?
They may occur before pregnancy is realised
What number of hospital admissions occur due to miscarriage annually?
42,000
What % of miscarriages occur in the first trimester?
85%
How does the risk of miscarriage change with gestational age?
Falls rapidly
What are the risk factors for miscarriage?
- Maternal age >30
- Cigarette smoke
- Excess alcohol
- Low pre-pregnancy BMI
- Paternal age >45 years
- Fertility problems and taking longer to conceive
- Illicit drug use
- Uterine surgery or abnormalities
- Uncontrolled DM
- Stress, anxiety or traumatic events
Why does risk of miscarriage increase with maternal age?
Due to risk of chromosomal abnormalities increasing
What are some protective factors against miscarriage?
- Previous live birth
- Nausea
- Healthy diet
Is a cause for miscarriage always identified?
No in many cases it isn’t
How does the prognosis of future pregnancies in miscarriage with an unidentifiable cause compare to a miscarriage with a known cause?
It is generally better
What are some identifiable causes of miscarriage?
- Chromosomal abnormalities
- Endocrine factors
- Maternal illness and infection
- Maternal lifestyle and drug history
- Abnormalities of the uterus
- Cervical incompetence
- Autoimmune factors
- Thrombophilic defects
- Alloimmune factors
What is the most common type of chromosomal abnormality?
Autosomal trisomies
What % of miscarriages due to chromosomal abnormalities are caused by autosomal trisomies?
50%
What endocrine factors can lead to miscarriage?
- Failure of corpus luteum
- PCOS
- Poorly controlled diabetes
- Untreated thyroid disease
Why can corpus luteum failure lead to miscarriage?
Progesterone production is predominantly dependant on the corpus luteum in the first 8 weeks
What maternal illnesses can lead to miscarriage?
- Severe febrile illness
- Syphilis
- Listeria
- Mycoplasma
- Bacterial vaginosis
- Other systems illness e.g. cardiac, renal or hepatic disease
What maternal lifestyle factors can lead to miscarriage?
- Smoking
- Alcohol use
- Caffeine
- Cocaine
- Cannabis
- Stress
What drug history can lead to miscarriage?
- Anti-depressant sue
- Peri-conceptual NSAID use
What uterine abnormalities can lead to miscarriage?
- Congenital abnormalities
- Asherman’s syndrome
What congenital abnormalities of the uterus can lead to miscarriage?
- Bicornuate uterus
- Subseptate uterus
Congenital uterine abnormalities are present in what % of women with recurrent miscarriage?
15-30%
What is Asherman’s syndrome?
Where damage to the endometrium and inner uterine walls cause the surfaces to become adherent, partially obliterating uterine cavity
When can cervical incompetence lead to?
2nd trimester miscarriage or early preterm delivery
How does a miscarriage due to cervical incompetence present?
Usually painless, rapid and bloodless
How can cervical incompetency be diagnosed?
- Passage of a Heger 8 dilator without difficulty in a non-pregnant woman
- USS
- Pre-menstrual hysterogram
What is the most common cause for cervical incompetency?
Physical damage by mechanical dilation of the cervix or during childbirth
What autoimmune factor can commonly cause miscarriage?
- Antiphospholipid antibodies
What % of women with recurrent miscarriage have antiphospholipid antibodies present?
15%
What is the live birth rate in women with untreated antiphospholipid syndrome?
As low as 10%
What is thought to cause pregnancy loss in antiphospholipid syndrome?
Thrombosis of uteroplacental vasculature and impaired trophoblast function
What other risks in pregnancy are associated with antiphospholipid syndrome?
- IUGR
- Pre-eclampsia
- Venous thrombosis
What is the commonest presentation of miscarriage?
Vaginal bleeding with pain worse than a period
What should be looked for on examination in suspected miscarriage?
- Signs of haemodynamic instability
- Abdominal distension with localised tenderness
- Assess diameter of os and look for products of conception on speculum
- Assess uterine tenderness and adnexal mass on bimanual
What are some signs of haemodynamic instability?
- Pallor
- Tachycardia
- Tachypnoea
- Hypotension
What are the types of miscarriage?
- Threatened miscarriage
- Inevitable miscarriage
- Missed miscarriage
- Incomplete miscarriage
- Complete miscarriage
- Recurrent miscarriage
- Septic miscarriage
What are the features of a threatened miscarriage?
- USS shows viable pregnancy
- Mild bleeding
- Usually little to no pain
- Os is closed
What percentage of women with a threatened miscarriage will go on to have a complete miscarriage?
50%
What is an inevitable miscarriage?
- Heavy bleeding with clots and pain
- Os is open
- Pregnancy will not continue
What is a missed miscarriage?
- Fetus is dead but retained
- History of threatened miscarriage and persistent, dark-brown discharge
- Decreased or absent early pregnancy symptoms
What is an incomplete miscarriage?
Products of conception are partially expelled
What is a complete miscarriage?
Confirmed uterine pregnancy in history followed by bleeding and clots with subsequent USS showing no pregnancy tissue in uterus
What is recurrent miscarriage?
3 or more consecutive miscarriages
What is a septic miscarriage?
When products of conception get infected
What are the features of a septic miscarriage?
- Fever
- Rigors
- Uterine tenderness
- Bleeding/discharge
- Pain
What might investigations show in septic miscarriage?
- Leucocytosis and raised CRP
- Features of complete or incomplete miscarriage
What are the differentials for a miscarriage?
- Ectopic pregnancy
- Hydatiform mole
- Cervical/uterine malignancy
When is a patient suspected for a miscarriage?
- Positive urine pregnancy test
- Vaginal bleeding with or without pain
What investigations should a patient with a suspected miscarriage receive initially?
- Transvaginal ultrasound scan in an early pregnancy assessment unit
- Serum beta-HCG
What must be looked for on USS in suspected miscarriage?
- Fetal cardiac activity
- Fetal crown-rump length
- Mean sac diameter and fetal pole
What is the most important finding on USS to exclude miscarriage?
Fetal cardiac activity
When can fetal cardiac activity normally be observed on transvaginal USS?
5.5-6 weeks gestation
Why is crown-rump length an important measure in assessing a suspected miscarriage?
To estimate gestation
When can a conclusive diagnosis of miscarriage not be made?
When CR length <7mm and no fetal heart activity detected
When should a scan be repeated if a conclusive diagnosis of miscarriage cannot be made due to CR length?
7 days later
How can an intrauterine pregnancy be confirmed on USS if fetal pole is not visible?
Gestational sac and yolk sac
What does the management of a suspected miscarriage depend on if using the gestational and yolk sacs to confirm intrauterine pregnancy?
Mean sac diameter
How is the mean sac diameter obtained?
By measuring the sac in three dimensions
When can a diagnosis of failed pregnancy be made based on mean sac diameter?
If >25mm
When must a repeat scan in 10-14 days be made based on mean sac diameter?
<25mm
When can a transabdominal USS be used to assess miscarriage?
If TVUS is not acceptable to the patient or in later gestation
Why is transabdominal USS not readily used to assess miscarriage?
It is less sensitive and specific
What can a serum beta-HCG be useful for in assessing suspected miscarriage?
Differentiating from an ectopic pregnancy
How can an ectopic pregnancy be differentiated from miscarriage using beta-HCG?
Serial measurements:
- Lowering suggests miscarriage
- Steady suggests ectopic
What other blood tests may be useful in suspected miscarriage?
- FBC
- Blood group and Rh status
- CRP
What are the three types of management for miscarriage?
- Conservative
- Medical
- Surgical
What do women require regardless of management if they are Rh -ve and > 12 weeks gestation in miscarriage?
Anti-D prophylaxis
What do women require if they are having surgical management for miscarriage and are Rh -ve regardless of gestation?
Ant-D prophylaxis
What is involved in conservative management of miscarriage?
Allowing the products of conception to pass naturally
What should patients have if choosing conservative management of miscarriage?
24 hour access to gynaecological services
What are the advantages of conservative management of miscarriage?
- Can remain at home
- No side effects
- No anaesthetic or surgical risk
What are the disadvantages of conservative management of miscarriage?
- Unpredictable timing
- Heavy bleeding and pain
- Chance of being unsuccessful and requiring further intervention
What follow up should be given for conservative management of miscarriage?
Either:
- Repeat scan in 2 weeks
- Pregnancy test in 3 weeks
What are the contraindications to conservative management of miscarriage?
- Infection
- High risk of haemorrhage e.g. coagulopathy or haemodynamically unstable
What is involved in medical management of miscarriage?
Use of vaginal misoprostol to stimulate cervical ripening and myometrial contractions
What is misoprostol?
A prostaglandin analogue
What is usually given 24-48 hours prior to misoprostol?
Mifepristone
What are the advantages of medical management of miscarriage?
- Can be at home if desires (with 24/7 access to gynae)
- Avoids anaesthetics and surgical risks
What are the disadvantages of medical management of miscarriage?
- Can cause vomiting and diarrhoea
- Heavy bleeding and pain
- Chance of emergency surgery required
What follow up is given in medical management of miscarriage?
Pregnancy test 3 weeks later
What are the types of surgical management miscarriage?
- Manual vacuum aspiration
- Evacuation of retained products of conception (ERPC)
Under what anaesthetic is manual vacuum aspiration performed?
Local
When can manual vacuum aspiration be performed?
If <12 weeks gestation
Under what anaesthetic is ERPC performed for miscarriage?
General
How is an ERPC for miscarriage performed?
- Speculum is passed to visualise cervix
- Cervix is dilated and suction tube passed to remove products of conception
What are the clinical indications for surgical management miscarriage?
- Persistent excessive bleeding
- Haemodynamic instability
- Evidence of infected retained tissue
- Suspected gestational trophoblast disease
What are the advantages of surgical management miscarriage?
- Planned procedure
- Can help patient cope
- Unaware during ERPC
What are the disadvantages of surgical management miscarriage?
- Anaesthetic risk
- Infection
- Uterine perforation
- Haemorrhage
- Asherman’s syndrome
- Bowel or bladder damage
- Retained products of conception
