Types of miscarriage syndromes:
1. Threatened miscarriage - this is diagnosed when there is painless vaginal spotting / bleeding (brown discharge would count as this is often altered old blood) and the fetus is either viable (or alive) on ultrasound scan or the pregnancy is at a stage that is too early to confirm the viability of the fetus (e.g. earlier than late 5 weeks).
2. Missed miscarriage - this is diagnosed when ultrasound scan confirms that the fetus is not viable.
Current ultrasound criteria for this diagnosis include:
a) At initial ultrasound scan
i) empty gestational sac (no fetus seen) with mean diameter >=25 mm
ii) Crown rump length (length of fetus) >= 7 mm with no fetal heart activity
iii) Beyond 70 days pregnancy with mean sac diameter >=18 mm with no fetus seen.
iv) Beyond 70 days pregnancy with crown rump length (length of fetus) >= 3 mm with no fetal heart activity
b) At a repeat scan
i) Absence of an embryo heartbeat >=14 days after an initial scan showing an empty gestational sac (without a yolk sac)
ii) Absence of an embryo heartbeat >= 11 days after an initial scan showing a gestational sac and yolk sac
iii) Absence of an embryo heartbeat >= 7 days after an initial scan showing an embryo with crown rump length < 7 mm with no heart activity
iv) Absence of an embryo heartbeat >= 7 days after an initial scan with an empty gestational sac where the mean sac diameter is >= 12 mm with no embryo
3. Inevitable miscarriage - this is diagnosed when there is vaginal bleeding associated with lower abdominal cramps, the internal opening of the cervix is already open on physical examination, and ultrasound examination still shows the fetus within the uterus (possibly in the lower part of the uterus).
4. Incomplete miscarriage - this is diagnosed when there is vaginal bleeding, lower abdominal cramps and passage of products of conception (dark coloured tissue), and the uterine cavity does not appear to be empty on ultrasound scan.
5. Complete miscarriage - this is diagnosed when there is vaginal bleeding, lower abdominal cramps and passage of products of conception (dark coloured tissue), and the uterine cavity appears to be empty on ultrasound scan. Often vaginal bleeding would have tapered off a lot by the time of the scan.
Risk of miscarriage according to mother's age
The risk of miscarriage increases with increasing age of the mother. Graph from wikipedia.
When to see doctor?
1. When there is a first episode of vaginal bleeding in pregnancy - whether it is painless or painful.
An ultrasound scan with a physical examination is required to differentiate between the different miscarriage syndromes and ectopic pregnancy.
If there is threatened miscarriage, there is some limited data that oral dydrogesterone may reduce the risk of miscarriage subsequently (https://www.ncbi.nlm.nih.gov/pubmed/22794306, https://www.ncbi.nlm.nih.gov/pubmed/20005647, https://www.ncbi.nlm.nih.gov/pubmed/20007011)
2. When there is excessive vaginal bleeding with amount like or exceeding a heavy day of a menstrual period / severe abdominal pain if there had already been a prior ultrasound scan documenting that the fetus is viable.
3. When you are very worried or anxious.
An ultrasound scan that shows that the fetus is viable would generally calm parents down a lot, and provide reassurance. Excessive anxiety and worry during pregnancy is not good, hence a timely ultrasound scan and assessment may be able to provide the reassurance that is required when there is continued vaginal bleeding or worry. In general, there is no need to scan more frequently than weekly when there is continued vaginal bleeding unless the bleeding is heavy or when there is severe abdominal pain.
1. Threatened miscarriage
a) Oral dydrogesterone - There is some limited data that oral dydrogesterone may reduce the risk of miscarriage subsequently. (https://www.ncbi.nlm.nih.gov/pubmed/22794306, https://www.ncbi.nlm.nih.gov/pubmed/20005647, https://www.ncbi.nlm.nih.gov/pubmed/20007011)
b) Other measures - physical / emotional rest (medical certificate) and avoidance of sexual intercourse are often advised though there is little data to support that these measures actually work.
I reviewed with a co-worker on "Non-Surgical Interventions for threatened and recurrent miscarriages" in 2007 (http://smj.sma.org.sg/4812/4812ra1.pdf ). It is still relevant 10 years later.
2. Missed miscarriage
Options include expectant (wait), medical and surgical treatments.
a) Expectant (wait) management up to 4 weeks may be appropriate if there is still doubt (medically or psychologically) about the diagnosis. While waiting, heavy bleeding with or without abdominal pain may ensue resulting in an incomplete or complete spontaneous miscarriage. If incomplete miscarriage, subsequent medical or surgical treatments may be required.
Most who have accepted the diagnosis would, however, opt for medical or surgical treatment.
b) Medical treatment - this involves the use of vaginal tablets containing prostaglandins that aim to stimulate painful menstrual cramps, bleeding and passage of conception. This may result in an incomplete (10-20%) or complete (80-90%) miscarriage. If incomplete miscarriage, subsequent repeat medical or surgical treatment may be required.
c) Surgical treatment - this involves surgically "cleaning" the cavity of the uterine cavity with vacuum aspiration and a metal curette (instrument shaped like a small spoon at the tip). Surgical risks are uncommon. These include bleeding, infection, cervical laceration and uterine perforation (in less than 1%).
In all of these methods, expectant management has the least success rates whilst surgical treatment has the highest success rates of a complete miscarriage. All the methods are associated with a similarly small (2-3%) risk of infection.
3. Incomplete miscarriage
Options include expectant up to 1-2 weeks, medical and surgical treatments as above.
4. Complete miscarriage
No need for medical or surgical treatment.
1. Use of intramuscular injection of Rhogam for pregnant with Rhesus negative blood group in many cases (especially those that require medical or surgical treatments)
2. Antibiotics in some cases.
Investigation of causes for miscarriages
Most cases of miscarriages are due to severe chromosomal or structural abnormalities of the fetus (usually random in nature). Other causes may include untreated maternal medical conditions (e.g. thyroid diseases, poorly controlled diabetes mellitus, antiphospholipid syndrome, etc).
A good history, karyotyping of the fetus upon a miscarriage and possibly blood tests to exclude antiphospholipid syndrome, diabetes mellitus and thyroid diseases may be indicated for recurrent miscarriages (>=2 to 3 consecutive miscarriages) or at least 1 late miscarriage (>=10 weeks).
When to try for another pregnancy?
Recent data has showed that a pregnancy within 3 months of a miscarriage is associated with the lowest risk of miscarriage (https://www.ncbi.nlm.nih.gov/pubmed/29112656). Hence there is no need to wait a long time to try for another pregnancy... unless the couple need more time to recover emotionally from the miscarriage.
Physical recovery after a miscarriage is almost always quick but emotional recovery may take a more variable time. Some may choose to do the confinement routine after a miscarriage but there is no need to medical reason to complete a prolonged confinement routine whilst delaying a trial for another pregnancy. I often advise couples to wait till after the next period after a complete miscarriage to try for another pregnancy UNLESS the couple requires more time to recover emotionally.