[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