Experiencing a miscarriage is emotionally devastating. When it happens repeatedly – defined as two or more consecutive pregnancy losses – it is classified as recurrent miscarriage (also called recurrent pregnancy loss). This affects approximately 1–2% of couples trying to conceive and warrants thorough investigation and specialised care.
Common Causes
Chromosomal Abnormalities
The most common cause of miscarriage is chromosomal abnormality in the embryo. As women age, the likelihood of eggs having chromosomal errors increases, which is why recurrent miscarriage becomes more common after 35. Rarely, one partner may carry a balanced chromosomal translocation that increases the risk of abnormal embryos.
Uterine Abnormalities
Structural problems with the uterus can interfere with implantation or pregnancy maintenance. These include a uterine septum (a wall dividing the uterine cavity), fibroids (especially submucosal fibroids that distort the cavity), uterine adhesions (Asherman’s syndrome), and cervical insufficiency.
Thrombophilia and Antiphospholipid Syndrome
Blood clotting disorders can compromise blood flow to the developing placenta, leading to pregnancy loss. Antiphospholipid syndrome (APS) is the most well-established treatable cause of recurrent miscarriage and is found in approximately 15% of women with recurrent loss.
Hormonal Factors
Uncontrolled diabetes, thyroid disorders, and PCOS can all increase miscarriage risk. Ensuring these conditions are well-managed before and during pregnancy is essential.
Diagnostic Workup
- Karyotyping of both partners to check for chromosomal translocations
- Pelvic ultrasound or hysteroscopy to assess uterine anatomy
- Blood tests for antiphospholipid antibodies and thrombophilia screening
- Thyroid function tests and blood sugar assessment
- Hormonal evaluation including progesterone levels
Treatment Options
- Progesterone supplementation: Evidence supports the use of progesterone in early pregnancy for women with a history of recurrent miscarriage.
- Blood thinners: Low-dose aspirin and heparin for women with antiphospholipid syndrome can significantly reduce miscarriage rates.
- Surgical correction: Removal of uterine septum, fibroids, or adhesions when they are contributing to pregnancy loss.
- IVF with PGT-A: Preimplantation genetic testing allows screening of embryos for chromosomal abnormalities before transfer, selecting only genetically normal embryos.
- Optimising underlying conditions: Strict control of diabetes, thyroid levels, and weight before attempting pregnancy.
The Outlook
Even after multiple miscarriages, the majority of couples go on to have a successful pregnancy with appropriate investigation and treatment. If you have experienced two or more pregnancy losses, seeking evaluation from a reproductive medicine specialist is an important step. Understanding the cause – when one can be found – allows for targeted treatment that can dramatically improve your chances of carrying a pregnancy to term.