Miscarriage

Miscarriage is the spontaneous loss of pregnancy prior to 24 weeks gestation. If there is loss of pregnancy at/after 24 weeks it is defined as a stillbirth. A lot of time miscarriage occurs with women not knowing they were pregnant at all. In recognised pregnancies around 10-24% end in miscarriage of which 80% occur in the first trimester (up to 12 weeks). Those pregnancies that make it to the second trimester (13-27) rarely end in miscarriage (1-2%) only. Remember though that the second trimester goes up until 27 weeks but the definition of miscarriage only includes the weeks up until the 24th week.

Recurrent miscarriage is defined as the loss of 3 or more pregnancies prior to 24 weeks gestation. We will discuss this separately at the end of this CCC.

Pathophysiology

Miscarriage alone is not indicative of pathology and is not a cause for concern unless it becomes recurrent. It is very difficult to pinpoint the pathophysiology and aetiology of every miscarriage. However, let’s look at some reasons that miscarriage might occur:

Very generally speaking, we can say that first trimester miscarriages are likely due to embryonic/foetal factors and second trimester miscarriages are due to maternal factors:

Other causes may be:

• Endocrinopathies
• Poorly controlled diabetes
• Poorly controlled thyroid disease
• Polycystic ovary syndrome
• Hyperprolactinaemia
• Advanced paternal age - lower quality sperm increases the likelihood of chromosomal abnormalities and miscarriage
• Thrombophilias
• Anti-phospholipid syndrome
• Cervical incompetence - this may be due to congenital causes, birthing injuries, LLETZ procedures or other factors.
• Uterine abnormalities

🔢 Classification

1. Incomplete miscarriages - a non-viable pregnancy that has been diagnosed and has begun bleeding but products of conception remain retained in the uterus. There may be bleeding and pain and the os is possibly open.
2. Complete miscarriage - all products of conception have been expelled and the uterus is empty. Bleeding has now stopped and the os is usually closed. There may have been pain + bleeding prior which alerted the patient to the miscarriage.
3. Inevitable miscarriage - this is called inevitable miscarriage as the os is open and there is heavy bleeding and pain, however, the foetus remains intrauterine. It will lead to foetal demise.
4. Threatened miscarriage - a confirmed intrauterine pregnancy in which a foetal heartbeat remains present but there is vaginal bleeding and the women is at risk of losing the foetus.
5. Missed miscarriage - also known as a delayed or silent miscarriage. The uterus still contains the foetus and products of conception but there is no foetal heartbeat and the foetus is no longer alive. The cervical os is closed and the woman is often asymptomatic.

😷 Presentation

• Vaginal bleeding
• Pain - the pain is similar to the cramps-like pain of menstruation but is reported to be worse.
• Vaginal tissue loss

🔍 Investigations

→ 🥇 Transvaginal ultrasound - rules out ectopic pregnancy which has similar presentation.

→ 🏆 Serial hCG measurements 48 hours apart:

1. Decreasing hCG levels - indicates that foetus will not develop or miscarriage has happened.
2. Slight increase or plateau in hCG levels - highly suggestive of ectopic pregnancy.
3. Normal increase in hCG (doubling every 48 hours) - normal growth of foetus but does not exclude ectopic pregnancy.

🧰 Management

We will discuss the management of miscarriage (expectant, medical and surgical). Before we do so, it is just important to consider the need for psychological support, especially if it is recurrent miscarriage. Cancellation of routine antenatal care is also important to ensure the ladies are not sent appointment reminders.

We have 3 potential aspects to management:

1. Expectant management
2. Medical management
3. Surgical management

👩‍⚕️

Surgical management of miscarriage:

Surgical intervention may be required if products of conception are retained despite medical treatment or it may be offered if the woman has ongoing symptoms after 14 days of expectant management.

Surgical options include:

• Manual vacuum aspiration - under local anaesthetic in an outpatient or clinic setting. Can only be done if <10 weeks gestation.
• Surgical management - in theatre under general anaesthesia. It is done vaginally with no incisions.

• Anti-D immunoglobulin - must be given to all rhesus-negative women undergoing surgical procedures.

• If a woman has vaginal bleeding and has a history of miscarriage → vaginal micronised progesterone (400mg BD) should be given once she has an intrauterine pregnancy confirmed by scan. It should be continued until 16 weeks gestation.

RECURRENT MISCARRIAGE

As mentioned previously, it can be due to:

1. Thrombophilias
2. Antiphospholipid syndrome
3. Cervical incompetence
4. Uterine abnormalities

🔍 🧰 Investigations/management:

Investigations should be undertaken for the cause of recurrent miscarriage for all women who have had:

• >3 miscarriages before 10 weeks of gestation
• >1 morphologically normal foetal losses after 10 weeks of gestation

This is likely to include antiphospholipid antibodies, generating abnormalities (in both partners), foetal genetic abnormalities (if foetal tissue is available), pelvic ultrasound scan (to detect uterine abnormalities).

It is also important to reassure women in whom no cause is found that the chance of prognosis for a future successful pregnancy is 75%.