A miscarriage is a condition of pregnancy loss before 24 weeks of gestation. 10-15% of pregnancies result in a miscarriage.
Recurrent miscarriage is the loss of three or more consecutive pregnancies, and affects approximately 1% of couples trying to conceive.
Gynaecological Conditions
Congenital uterine malformations (e.g. uterine septum) and acquired uterine conditions (e.g. adhesions and scarring in the uterus) can increase the risk of recurrent miscarriage. This may be detected by an ultrasound scan.
Congenital and acquired cervical weakness and abnormalities might cause the cervix to dilate too early in the pregnancy, resulting in miscarriage.
Hormonal Conditions
Diabetes, thyroid problems (hypothyroidism, hyperthyroidism, anti-thyroid antibodies) and polycystic ovarian syndrome (PCOS) may increase the risk of recurrent miscarriage, particularly if the condition is not well-controlled.
Inherited and acquired deficiency of anticoagulant proteins can increase the risk of blood clot formation.
Autoimmune conditions such as antiphospholipid syndrome (APS) increase blood clotting which affects the flow of nutrients to the fetus, leading to recurrent miscarriage.
These can be detected through blood tests. Treatment may involve aspirin and anticoagulants to decrease blood clotting.
Chromosomal Abnormalities
The chromosomes in our cells carry information for them to function. One copy of each pair of chromosomes is inherited from each parent, with a total of 23 pairs in humans.
In some cases, one parent has a chromosomal rearrangement – when parts of two different chromosomes break off and rejoin to the other chromosome to produce a new arrangement, in the form of a balanced translocation.
While this may not manifest with physical symptoms in the parent, the baby might inherit the abnormal chromosome. In this case, the child may
Chromosomal analysis involves examining your genetic material to identify chromosomal abnormalities that might contribute to recurrent miscarriage. This is done through a blood sample, and involves looking at the number, size, and structure of the chromosomes.
However, chromosomal analysis cannot identify genetic mutations in the chromosome or disorders that do not arise from chromosomal abnormalities.
Genetic counselling for future pregnancy plans is recommended, where results of the genetic testing will be used to clarify risk and options available.
Depending on the genetic testing results, you may consider:
While 50% of recurrent miscarriage cases have no identified cause, testing can offer clues about potential risk factors that can be used to advise on future pregnancies. Even with no cause, about 70% of couples have a next successful pregnancy till full-term without any treatment or medication.
Couples experiencing recurrent miscarriage should seek medical advice promptly for guidance on testing to identify the potential causes. Consult your gynaecologist for management guidance.
We understand that recurrent miscarriage can put women and couples under tremendous stress. If you are struggling, consider talking to your family doctor for mental health support options.
For further enquires, you may contact us.
Department of Clinical Genetics
Address: Specialist Outpatient Clinic, 1/F, Tower B, Hong Kong Children's Hospital, 1 Shing Cheong Road, Kowloon Bay, Kowloon, Hong Kong
Office Tel: 5741 3186
DCG – Recurrent Miscarriage
JUNE 2024