(Information for the public according to the Royal College of Obstetricians and Gynaecologists – for further information, women should consult their gynaecologist.)

GENERAL INFORMATION

• Miscarriage is the early loss of a pregnancy.
• Recurrent miscarriage is when this happens three or more times.
• About 1 in 100 women (1%) experience recurrent miscarriages.
• Most couples who have had recurrent miscarriages in the past have a good chance of having a successful pregnancy in the future.
• If you have had recurrent miscarriages, you should have blood tests and an ultrasound examination of your pelvis to find out the cause.
• Despite these tests, in many cases the cause cannot be found.
• Your doctor cannot tell you with certainty what the course of your next pregnancy will be if you become pregnant again.

WHAT IS RECURRENT MISCARRIAGE?

A miscarriage is the loss of a pregnancy before 23 weeks of gestation. When this happens three or more times, it is called recurrent miscarriage. For women and their partners, it is a very distressing experience. About 1 in 100 women experience recurrent miscarriage. This is three times more common than what would be expected by chance, which means that for some women, there is a specific cause. For others, no identifiable cause exists with current medical knowledge, and the miscarriages seem to occur by chance.

WHY DOES THIS HAPPEN?

In many cases, even after thorough testing, the cause cannot be found. However, if you and your partner feel emotionally and physically ready to continue trying, you have a good chance of a successful pregnancy in the future.

Many factors are involved in miscarriage, and research is ongoing to clarify their roles.

• Your age and previous pregnancies
The older you are, the higher your risk of miscarriage. Likewise, the more miscarriages you have had, the more likely you are to miscarry again.
• Genetic factors
About 3 to 5 in 100 couples with recurrent miscarriage have a chromosomal abnormality in one partner. While these abnormalities do not cause health problems for the parents, they can lead to problems in the embryo.
• Abnormalities in the embryo
An embryo is a fertilized egg. Chromosomal abnormalities in the embryo are the most common cause of sporadic miscarriages. However, the more miscarriages you have, the less likely this is the cause.
• Immune factors
Antibodies are substances produced by the body to fight infections. About 15 in 100 women with recurrent miscarriage have antibodies known as antiphospholipid antibodies. Fewer than 2 in 100 women with normal pregnancies have these antibodies. If you have antiphospholipid antibodies and a history of recurrent miscarriage, your chance of a successful pregnancy may be about 1 in 10 without treatment.
• Uterine abnormalities
Major uterine malformations can increase miscarriage risk. Estimates vary widely, from 2 in 100 to 37 in 100 among women with recurrent miscarriage. Severe malformations that are untreated increase the risk of miscarriage or preterm birth. Minor anomalies usually do not.
• Cervical insufficiency
In some women, the cervix (the entrance to the uterus) opens too early, leading to miscarriage in the second trimester. This is called cervical insufficiency. It is often overdiagnosed, as there is no reliable test outside pregnancy.
• Polycystic ovaries
Women with polycystic ovaries have slightly enlarged ovaries that produce many small follicles, sometimes linked to hormonal imbalance. About half of women with first-trimester recurrent miscarriages have polycystic ovaries, nearly double that of the general population. Polycystic ovaries are not a clear cause of recurrent miscarriage, and the link between the two remains unclear.
• Hyperprolactinemia
Prolactin is the hormone that prepares the breasts for milk production. When levels are high, it’s called hyperprolactinemia. It’s unclear whether this plays a role in recurrent miscarriage.
• Infections
Severe infections that spread through the blood may cause miscarriage. A vaginal infection early in pregnancy called bacterial vaginosis (often due to Gardnerella) may increase the risk of miscarriage or preterm birth. However, infections are not known to cause recurrent miscarriage. Routine screening for diseases like herpes, rubella, toxoplasmosis, listeria, or CMV is not recommended.
• Blood clotting disorders (thrombophilias)
Inherited blood disorders known as thrombophilias cause the blood to clot more easily. Although they may play a role, the exact mechanism remains unclear.
• Alloimmune reaction
Some researchers suggest that the immune system may recognize the fetus as a foreign body and reject it. There is insufficient evidence to support this theory.
• Diabetes and thyroid disease
When properly treated and controlled, these conditions do not cause recurrent miscarriage.

WHAT CAN I DO?

Emotional support before pregnancy
Women who receive emotional and psychological support before conception have higher success rates.

Check for uterine abnormalities
You should have an ultrasound examination to detect possible uterine abnormalities. In some cases, a hysterosalpingogram (X-ray with contrast fluid) may be performed, but it offers no clear advantage and causes more discomfort.

Genetic testing
You and your partner should have chromosomal testing (karyotype). If abnormalities are found, a clinical geneticist can advise you on risks and options for future pregnancies.

Testing the embryo
If you have a history of recurrent miscarriage and lose another pregnancy, your doctor may recommend testing the embryo’s chromosomes (karyotype) and examining the placenta under a microscope. These results can help guide treatment.

Testing for vaginal infections
If you have second-trimester miscarriages or preterm birth, you should be tested for bacterial vaginosis and treated if necessary.

Treatment for antiphospholipid antibodies
Evidence shows that women with antiphospholipid antibodies and recurrent miscarriage benefit from treatment with low-dose aspirin and low-molecular-weight heparin early in pregnancy. This increases the chance of a live birth to about 70% (compared to 40% with aspirin alone and 10% with no treatment). Even with treatment, there remains a risk of complications such as preeclampsia, fetal growth restriction, or preterm birth.

Treatment for thrombophilia
Even if you have thrombophilia, you can still have a normal pregnancy. There is no specific test to predict miscarriage in these women, but treatment may be given to reduce blood clot risk.

Cervical insufficiency treatment
If you have cervical insufficiency, a vaginal ultrasound during pregnancy can assess the risk. If needed, your doctor may recommend a cerclage procedure (stitching the cervix closed). While this may slightly reduce preterm birth risk, it does not guarantee a higher survival rate. The benefits and risks should be discussed with your doctor.

Hormonal therapy
It has been suggested that progesterone or hCG early in pregnancy might prevent miscarriage, but there is not enough evidence that it works.

Immunotherapy
Treatments designed to alter immune responses (known as immunotherapy) are not recommended for recurrent miscarriage. They have not been proven effective and can carry serious risks such as allergic reactions, infection, or transmission of hepatitis or HIV.

WHAT TO EXPECT IN THE FUTURE

Your doctor cannot predict the outcome of your next pregnancy with certainty. However, even if no cause has been identified, you have a very good chance (three in four) of having a normal pregnancy. Keep in mind that no treatment works for everyone every time.

Dr. Babatsias
Dr. LAMBROS BABATSIAS
OBSTETRICIAN – GYNAECOLOGIST SURGEON
Trained in London in Laparoscopy and Hysteroscopy (University Dept. of Obstetrics and Gynaecology – Royal Free Hospital – London)

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