Miscarriage Flashcards
Miscarriage
Miscarriage is the spontaneous loss of an intrauterine pregnancy before 24 weeks gestation. It occurs in approximately 10 – 24% of all clinical pregnancies
Risk factors for miscarriage
Increasing maternal age and the number of previous miscarriages.
Most miscarriages (~80%) are diagnosed under 13 weeks, with the risk of miscarriage decreasing as gestational age increases.
Most common cause of miscarriage in the 1st trimester
Chromosomal abnormality (50-60%).
Autosomal trisomy is the most common abnormality (e.g. trisomy 16). The most common single chromosomal anomaly is 45X karyotype.
Most common cause of miscarriage in the 2nd trimester
An incompetent cervix (e.g. due to previous cervical surgery) or systemic maternal illness.
There are 5 types of miscarriage; what are they?
- Threatened miscarriage
- Inevitable miscarriage
- Incomplete miscarriage
- Complete miscarriage
- Other types of miscarriage:
Threatened miscarriage
Occurs when there is vaginal bleeding but the cervical os is closed, and ultrasound shows a viable intrauterine pregnancy.
Most threatened miscarriages do not result in the loss of the pregnancy.
Inevitable miscarriage
Refers to vaginal bleeding with an open cervical os, either with or without cramping abdominal pain. In this situation, pregnancy loss will occur (i.e. inevitable).
Incomplete miscarriage
Occurs when there is vaginal bleeding, an open cervical os and products of conception are seen on examination.
Complete miscarriage
When the products of conception have passed, the cervical os is closed and ultrasound shows an empty uterine cavity.
Other types of miscarriage apart from threatened, inevitable, incomplete & complete.
a. Missed miscarriage: the presence of a nonviable intrauterine pregnancy that has not yet resulted in symptoms or the passage of the products of conception.
b. Recurrent miscarriage: the occurrence of three or more miscarriages.
What is a missed miscarriage?
The presence of a nonviable intrauterine pregnancy that has not yet resulted in symptoms or the passage of the products of conception.
Examinations for miscarriage
Vital signs recorded using an obstetric or maternal early warning chart.
Abdominal examination should be performed to assess for signs of an acute abdomen
A speculum to assess the cervical os, rule out other sources of bleeding (e.g. cervical/vaginal pathology), quantify the bleeding and assess for visible products of conception.
If an ectopic pregnancy is suspected, a bimanual examination should also be performed.
Laboratory tests for management of miscarriage
Full blood count
Beta-HCG:
Group and save / cross-match: if significant bleeding
Antibody screen: rhesus negative women
Why should an antibody screen be done for surgical procedures (miscarriage, labour)?
Rhesus negative women undergoing a surgical procedure to manage miscarriage will require anti-D rhesus prophylaxis
Imaging in miscarriage
A transvaginal ultrasound
If the ultrasound scan is inconclusive for an intrauterine pregnancy (i.e. there is a pregnancy of unknown location), serial beta-HCG measurements are performed.
How much should serum beta-HCG increase in a progressing pregnancy?
Should increase by more than 63% in 48 hours in a progressing pregnancy.
Beta-HCG levels that fall by more than 50% in 48 hours indicate a failing pregnancy (potential miscarriage).
Beta-HCG levels that fall by less than 50%, or fail to rise by more than 63%, over 48 hours require clinical review to exclude an ectopic pregnancy.
Emergency management of haemodynamically unstable patient in miscarriage.
Patients who present with significant haemorrhage, and/or evidence of haemodynamic instability, require an ABCDE approach.
A speculum examination should be performed, and products of conception should be removed.
Continued bleeding in a haemodynamically unstable patient warrants surgical management.
Why are products of conception in the cervical os dangerous in miscrriage?
Products of conception in the cervical os can lead to cervical shock due to vagal stimulation
What are the surgical management options for miscarriage?
Manual vacuum aspiration
Surgical evacuation
Manual vacuum aspiration
under local anaesthetic. involves manual suction aspiration of the uterus
Surgical evacuation
under general anaesthetic, an electronic suction device is used to remove products of conception
When is surgical management of miscarriage required?
Should be performed in patients with significant bleeding who have retained products of conception. Surgical management is also used when medical management or expectant management has been unsuccessful.
Rhesus negative patients undergoing surgical management of miscarriage should be given anti-D rhesus prophylaxis.
Medical management of miscarriage
Involves the use of a prostaglandin agent (misoprostol) to induce uterine contractions and effacement (empty) of the cervix.
Example of prostaglandin agent
Misoprostol
