When Is Formal Investigation Recommended?
RCOG (Royal College of Obstetricians and Gynaecologists) guidelines define recurrent miscarriage as 3 or more pregnancy losses before 24 weeks of gestation. Investigation is recommended after 3 losses. However, investigation after 2 losses is reasonable in private settings — particularly if the patient is over 35, has taken a long time to conceive, or is experiencing significant psychological distress. Earlier investigation is always appropriate where a specific risk factor is identified.
Any pregnancy loss, whether or not formal investigation criteria are met, warrants a compassionate consultation to discuss what happened, what is known about the cause, and what the outlook is for the future.
What Are the Causes of Recurrent Miscarriage?
A cause is identified in approximately 50% of couples who undergo full investigation. The main identifiable causes include:
- Antiphospholipid syndrome (APS): An autoimmune condition causing abnormal clotting. Found in around 15% of women with recurrent miscarriage. Identified by testing for antiphospholipid antibodies on two occasions at least 12 weeks apart. Treated with low-dose aspirin and low-molecular-weight heparin in pregnancy — this significantly improves live birth rates.
- Chromosomal abnormalities: In either partner, affecting around 2–5% of couples with recurrent miscarriage. The most common is a balanced chromosomal translocation — the carrier is healthy but at increased risk of chromosomally abnormal embryos. Genetic counselling and referral to a clinical genetics team follows a positive parental karyotype.
- Uterine structural abnormalities: Found in 10–15% of women with recurrent miscarriage. Include uterine septa, fibroids (particularly submucous fibroids), and polyps. Diagnosed on pelvic ultrasound or hysteroscopy. Many are correctable surgically.
- Thrombophilia: Inherited clotting disorders such as Factor V Leiden and prothrombin gene mutation. Their role in recurrent miscarriage is debated — they are associated more strongly with late pregnancy loss than early loss.
- Thyroid disease: Both hypothyroidism and thyroid autoimmunity (anti-thyroid antibodies) are associated with increased miscarriage risk.
In approximately 50% of cases, no cause is found. Even then, with appropriate specialist support, around 75% of women will have a successful subsequent pregnancy.
Recommended Investigations
The RCOG recurrent miscarriage investigation panel includes:
- Antiphospholipid antibodies: lupus anticoagulant, anticardiolipin antibodies (IgG and IgM), anti-beta2-glycoprotein-1 antibodies (IgG and IgM) — tested on two occasions 12 weeks apart
- Thrombophilia screen: Factor V Leiden, prothrombin gene mutation, protein C and S, antithrombin III
- Parental karyotyping: chromosomal analysis of both partners
- Thyroid function and thyroid antibodies
- Pelvic ultrasound: to assess uterine anatomy and detect structural abnormalities
- Hysteroscopy: direct visualisation of the uterine cavity, arranged by a specialist where abnormality is suspected or confirmed on ultrasound
How We Can Help
At Lambert Medical Practice, a private gynaecology consultation for recurrent miscarriage allows us to take a full history, initiate the appropriate blood tests, arrange a pelvic ultrasound, and provide a compassionate explanation of the investigation process. We will refer to a recurrent miscarriage specialist where indicated. You should not have to wait months for answers.