Miscarriage Flashcards
What is the definition of miscarriage?
the spontaneous termination of pregnancy before 24 weeks gestation
spontaneous termination after 24 weeks = stillbirth
What is an early and late miscarriage?
early:
- occurs in the first 12 weeks of pregnancy
late:
- occurs between 12 - 24 weeks gestation
What is a missed miscarriage?
- the foetus is no longer alive
- no symptoms have occurred
- often diagnosed through routine antenatal scans
also called a “silent miscarriage”
What is a threatened miscarriage?
- there is vaginal bleeding with a closed cervix
- the foetus is still alive
- this does not necessarily mean that the patient will go on to have a miscarriage
What is an inevitable miscarriage?
- there is a diagnosed non-viable pregnancy
- there is vaginal bleeding and an open cervical os
- the pregnancy will proceed to an incomplete or complete miscarriage
- pregnancy tissue still remains within the uterus at this stage
What is an incomplete miscarriage?
- miscarriage occurs and bleeding has begun
- the cervical os is open
- there are retained products of conception in the uterus following miscarriage
What is a complete miscarriage?
- a full miscarriage has occurred
- there are NO products of conception left in the uterus
- the bleeding has now stopped and the cervix is closed
What is an anembryonic pregnancy?
a gestational sac is present but it contains no embryo
How is a miscarriage diagnosed?
transvaginal USS
What 3 features are looked for on transvaginal US to determine the viability of a pregnancy?
- mean gestational sac diameter
- foetal pole + crown-rump length
- fetal heartbeat
these appear sequentially so as each feature develops, the previous becomes less relevant in determining viability of a pregnancy
When is a fetal heartbeat expected to be seen?
What does this mean for the pregnancy?
- fetal heartbeat is expected to be seen when CRL is 7mm or more
- the presence of a heartbeat means that the pregnancy is viable
What is done when there is a CRL < 7mm and NO fetal heartbeat?
the scan is repeated after 1 week to ensure that a heartbeat develops
What is done when the CRL is > 7mm and the fetal heartbeat is not present?
- the scan is repeated after 1 week
- if the fetal heartbeat still cannot be seen, this is deemed a non-viable pregnancy
How is an anembryonic pregnancy diagnosed on transvaginal USS?
- a fetal pole is expected once mean gestational sac diameter is 25mm or more
- if the MGSD is >25mm and there is no fetal pole, scan is repeated after 1 week
- if the fetal pole is still not present, this is an anembryonic pregnancy
What is the management for miscarriage occurring before 6 weeks gestation?
expectant management
- this involves awaiting the miscarriage without investigations / treatment
- as long as they do not have pain / complications / RFs
a scan is not performed as the pregnancy will be too small to be seen at this stage
How can miscarriage be confirmed following expectant management?
- a repeat urine pregnancy test is performed after 7-10 days
- miscarriage is confirmed if it is negative
if bleeding continues or pain occurs, further investigation is needed
What is the first stage in management of a suspected miscarriage after 6 weeks gestation?
- women are referred to an early pregnancy assessment unit if they have a positive PT and bleeding
- an USS is arranged to confirm the location + viability of the pregnancy
- this can also exclude ectopic pregnancy
What are the 3 options for managing a miscarriage after 6 weeks gestation?
- expectant management
- medical management with misoprostol
- surgical management
When is expectant management recommended following miscarriage > 6 weeks gestation?
- first-line option for women without RFs for heavy bleeding or infection
- 1-2 weeks are given to allow the miscarriage to occur spontaneously
- repeat urine PT performed 3 weeks after bleeding + pain settles to confirm the miscarriage is complete
What is involved in medical management of a miscarriage?
- misoprostol is given to expedite the process of miscarriage
- this can be given orally or as a vaginal suppository
How does misoprostol work?
- it is a prostaglandin analogue
- it binds to prostaglandin receptors to activate them
- this results in softening of the cervix and stimulation of uterine contractions
What are the side effects of misoprostol?
- heavier bleeding
- pain
- vomiting
- diarrhoea
What are the 2 surgical options for managing miscarriage?
- manual vacuum aspiration (MVA) under local anaesthetic
- electric vacuum aspiration (EVA) under general anaesthetic
What is given to all patients prior to surgical management of miscarriage?
misoprostol
- prostaglandins are given to soften the cervix prior to surgical management
What is involved in manual vacuum aspiration (MVA)?
- local anaesthetic is applied to the cervix
- a tube attached to a syringe is inserted through the cervix into the uterus
- the syringe is used to manually aspirate the contents of the uterus
What are the criteria for performing MVA?
- women must be below 10 weeks gestation
- it is more appropriate for parous women (who have previously given birth)
What is involved in electric vacuum aspiration?
- performed under general anaesthetic
- the cervix is gradually widened using dilators
- the products of conception are removed through the cervix using an electric-powered vacuum
What needs to be administered to women prior to surgical management of miscarriage?
anti-D must be given to rhesus negative women prior to the procedure
What is the associated risk of an incomplete miscarriage?
- the retained products of conception remain in the uterus after conception
- this may be fetal or placental tissue
- retained products create a risk of infection
What are the 2 options for management of an incomplete miscarriage?
- medical management with misoprostol
- surgical management
What is involved in the surgical management of incomplete miscarriage?
evacuation of retained products of conception (ERPC)
- involves general anaesthetic
- the cervix is gradually widened using dilators
- the retained products are removed using vacuum aspiration + curettage (scraping)
What is the main risk associated with ERPC?
endometritis following the procedure
(infection of the endometrium)
How is recurrent miscarriage defined?
when an individual has 3 or more consecutive miscarriages
When are investigations for the underlying cause of miscarriage initiated?
- after 3 or more first-trimester miscarriages
OR
- after 1 or more second-trimester miscarriages
What are the potential underlying causes of recurrent miscarriage?
- idiopathic (especially in older women)
- antiphospholipid syndrome
- hereditary thrombophilias
- uterine abnormalities
- genetic factors in parents
- chronic histiocytic intervillositis
- chronic diseases
common chronic diseases = uncontrolled thyroid disease, diabetes + SLE
What is antiphospholipid syndrome?
- an autoimmune disorder associated with antiphospholipid autoantibodies
- the patient is in a hypercoagulable state
- it is associated with increased risk of thrombosis + complications during pregnancy
Who tends to be affected by antiphospholipid syndrome?
- it typically affects women around the age of 30-40
- it is associated with other autoimmune conditions, particularly systemic lupus erythematosus (SLE)
How is antiphospholipid syndrome diagnosed and managed?
- test for the presence of antiphospholipid antibodies
- managed with BOTH low dose aspirin and low molecular weight heparin (LMWH)
- this manages the risk of miscarriage and VTE
What hereditary thrombophilias are most commonly associated with recurrent miscarriage?
- Factor V Leiden
- factor II (prothrombin) gene mutation
- protein S deficiency
What uterine abnormalities can result in recurrent miscarriage?
- uterine septum
- unicornate uterus
- bicornate uterus
- didelphic uterus
- cervical insufficiency
- fibroids
What is a septate uterus?
a thin tissue membrane (septum) runs down the middle of the uterus, splitting it into 2 parts
What is a unicornate uterus?
- a congenital abnormality in which only half of the uterus forms
- there is only one working fallopian tube
- there is a smaller uterine cavity
also known as a “single horn” uterus
What is a bicornate uterus?
a uterus that is divided into 2 parts by a deep indentation at the top
also called a “heart-shaped uterus”
What is a didelphic uterus?
- the presence of 2 uteruses
- also called a “double uterus”
- the individual also has 2 cervixes
this is different to a bicornate uterus, in which there is only one cervix
What is chronic histiocytic intervillositis?
- histiocytes + macrophages build up in the placenta
- the mother’s immune system reacts abnormally to the pregnancy
- this causes inflammation + adverse outcomes
- causes recurrent miscarriage (usually 2nd trimester), IUGR + IUD
the condition is poorly understood and is rare
How is chronic histiocytic intervillositis diagnosed?
placental histology
- shows infiltrates of mononuclear cells in the intervillous spaces
- it commonly recurs, so needs specialist management
What investigations are performed in recurrent miscarriage?
- antiphospholipid antibodies
- testing for hereditary thrombophilias
- pelvic USS
- genetic testing of parents
- genetic testing of products of conception from 3rd or future miscarriages
