Recurrent Miscarriage and Implantation Failure: Causes, Tests and Support
Clinical content by Trevor Wing MBRCP FRCHM MBAcC BSc (Hons) MSc (Dist) DMed (Img). Last reviewed October 2026.
Key facts
- About 1 in 5 known pregnancies ends in miscarriage, most often because of a chromosome problem in the pregnancy.
- Recurrent miscarriage, three or more losses, affects about 1 in 100 couples.
- Even after three miscarriages, most women go on to have a successful pregnancy.
- Recommended tests include antiphospholipid antibodies, thyroid function, genetic testing of pregnancy tissue and a pelvic ultrasound.
- We offer supportive early pregnancy scanning at our Twickenham clinic.
What is recurrent miscarriage?
Miscarriage is the loss of a pregnancy before 24 weeks. It is very common: around one in five known pregnancies miscarries, and the risk rises with age, particularly after 35. Under UK guidance from the Royal College of Obstetricians and Gynaecologists (RCOG), recurrent miscarriage is defined as three or more first-trimester miscarriages, which do not need to be consecutive, or two or more later miscarriages. Some clinics offer tests after two losses, especially for women over 35 or with fertility concerns.
Implantation failure describes repeated failure of good-quality embryos to implant, usually after IVF, and shares some possible causes with recurrent miscarriage.
What causes miscarriage?
- Chromosome problems in the pregnancy, the most common cause, which become more frequent as egg quality declines with age
- Antiphospholipid syndrome, an immune condition that makes blood more likely to clot
- Thyroid problems, including raised thyroid antibodies
- Structural problems in the womb, such as a uterine septum or some fibroids
- Lifestyle factors, including smoking, high caffeine and alcohol intake and being very underweight or overweight
- A balanced chromosome rearrangement in either parent, which is uncommon
In around half of couples with recurrent miscarriage, no clear cause is found. This is hard to hear, but the outlook for a future successful pregnancy is still good.
What is a blighted ovum?
A blighted ovum, or anembryonic pregnancy, is when a pregnancy sac develops but no embryo grows. Pregnancy hormones may still rise, so the diagnosis is usually made on an early ultrasound scan. It is most often caused by a chromosome problem and usually happens only once. Management options include waiting for the miscarriage to happen naturally, medication or a minor procedure, and the choice is yours to make with your doctor.
What tests are recommended after recurrent miscarriage?
- Blood tests for antiphospholipid antibodies (lupus anticoagulant and anticardiolipin antibodies), repeated to confirm a positive result
- Thyroid function and thyroid antibody tests
- Genetic testing of tissue from the pregnancy, and parental chromosome tests if an abnormality is found
- A pelvic ultrasound, ideally 3D, to look at the shape of the womb
- Inherited clotting tests after a second-trimester loss
Our 3D ultrasound on the GE Voluson S10 is well suited to assessing the shape of the womb.
What about immune testing and natural killer (NK) cells?
The role of the immune system in miscarriage and implantation failure, including natural killer (NK) cells and leukocyte antibodies, is an active area of research and a long-standing interest of our clinic. However, current RCOG guidance does not recommend routine immune testing or immune treatments such as IVIg outside research, because the evidence is not yet strong enough to show they improve live birth rates. If you are considering these tests, we will explain what is known and what is uncertain so you can decide for yourself.
What treatments are available?
- Antiphospholipid syndrome: low-dose aspirin and heparin injections in pregnancy significantly improve live birth rates.
- Progesterone: NICE recommends vaginal progesterone for women with bleeding in early pregnancy who have had a previous miscarriage.
- Thyroid treatment where tests are abnormal.
- Surgery for some womb abnormalities, such as removing a uterine septum.
- Folic acid: 400 micrograms daily before conception and for the first 12 weeks, or a higher dose if your doctor advises.
How do we support women at the Women’s Natural Health Clinic?
We provide a calm, supportive setting for women who have experienced pregnancy loss, working alongside your GP, recurrent miscarriage clinic or fertility unit. Your plan may include:
- Preconception care: nutrition, healthy weight, stopping smoking and limiting caffeine and alcohol.
- Chinese herbal medicine and acupuncture, chosen according to your pattern. In Traditional Chinese Medicine, repeated miscarriage is described as “slippery fetus” and is often linked to Kidney deficiency, particularly in women in their late 30s and 40s.
- Cycle monitoring to check ovulation and the second half of the cycle.
- Early pregnancy scans for reassurance and close monitoring once you conceive.
Frequently asked questions
How many miscarriages before I can be tested?
In the UK, tests are usually offered after three first-trimester miscarriages, which do not need to be in a row. Some clinicians offer tests after two, especially if you are over 35 or have had difficulty conceiving.
Will I have a successful pregnancy after recurrent miscarriage?
Most women do. Even after three miscarriages, more than half go on to have a successful next pregnancy, although the chance depends on age and the number of previous losses.
Should I have NK cell and LAD testing?
We are happy to talk through the evidence with you.
How long should I wait to try again after a miscarriage?
If you feel physically and emotionally ready, there is usually no medical need to wait. Many couples wait for one normal period, allowing the womb lining to return to normal and making dating a new pregnancy easier.
Book a consultation
To book, book an appointment online or call 020 3811 8778. Initial consultations last up to one hour at our clinic at 16 Bridle Lane, St Margaret’s, Twickenham TW1 3EE.