Recurrent Miscarriage

Recurrent Miscarriage is defined as a history of three or more consecutive spontaneous miscarriages. Recurrent pregnancy loss affects 1-2% (2 out of 100) of healthy fertile women. This recurring loss is often very distressing for couples, especially as there is still a limited understanding of the problem. In most cases, the cause is not apparent and can involve detailed investigations. Investigations to try and determine the cause may be considered in older or particularly anxious women after 2 miscarriages.

It is important for couples to understand that recurrent miscarriage is a specialist area and tests need to be undertaken and interpreted with expert medical guidance. The information below is to help couples have a better understanding of their situation, after consultation with specialists.

The table below shows some of the causes of recurrent miscarriage along with the recommended investigations. Further information about each specific cause is provided below the table.

Prevalence (%)
Recommended Test
>50% Unexplained (Idiopathic) -
10 – 25% Antiphospholipid syndrome LAC/ACA (Blood Tests)
<10% Oligomenorrhoea
Bacterial Vaginosis
Hormonal profile & Scan
Vaginal swabs
<5% Parental Chromosomal AnomalyUterine/Cervical Anomaly
Karyotype both partners

Unexplained – (50%)

This accounts for most of the cases. It is a diagnosis by exclusion. Fetal heart activity is never seen and loss usually occurs before 8 weeks. Fetal chromosomal anomalies occur in about 50% of sporadic and possibly recurrent pregnancy loss, usually >37years of age and at <10weeks of gestation.

The two main predictive factors for a future successful pregnancy are maternal age and the number of previous losses. For example at age 30, there is an 80% chance after 3 and a 71% chance of a successful pregnancy after 5 miscarriages. At age 40, this drops to 64% and 52% after 3 and 5 losses.

Treatment: Early pregnancy assessment, using `tender loving care` (TLC), and regular scans provides adequate support, providing reassurance to anxious women. Hormone treatment or immunological therapy – not recommended as not shown to improve pregnancy outcome.


Women with cycle lengths of >35 days regularly are at higher risk of recurrent pregnancy loss (usually 6-8 weeks, fetal heart never seen). This is seen in 10-15% of women with recurring miscarriage compared to 1% of general population. The miscarriage is usually of normal karyotype. HCG therapy for this group may improve pregnancy outcome.

Parental chromosomal anomalies

Occur in about 4% of couples compared with 0.2% in the normal population. Balanced translocation is the most common of all chromosomal abnormalities. Genetic counselling and checking family members may be advised, depending on individual cases.

Antiphospholipid syndrome (APS)

With APS pregnancy loss often occurs after 10 weeks of gestation. Fetal heart activity is seen and then lost on scans, unlike in idiopathic cases.

APS may be responsible for upto 30% of cases in women with mid trimester loss ( after 14 weeks), but may be seen with first trimester loss (15%). 10% of women with mid trimester loss may have more than one cause. To fulfil diagnostic criteria, the patient should have:

  1. At least one of the following clinical features:
    1. Recurrent (three or more) pregnancy loss
    2. Intrauterine death in second or third trimester
    3. Pre-eclampsia
    4. Intrauterine growth restriction


  2. Abnormal result of one of the following blood tests on more than one occasion (2 separate measurements, at least 6 weeks apart)
    1. Prolonged DRVTT (dilute Russell viper venom test) for lupus anticoagulant (LAC)
    2. IgG or IgM anticardiolipin antibody (ACA)

Women with recurrent pregnancy loss and positive APS should be managed by specialists. Low dose aspirin is often used in the pregnancy. Heparin may be added, especially, if history of maternal thrombosis. Consider postnatal thromboprophylaxis for 6 weeks, if other risks factors.


Thrombophilias such as Protein C and S deficiency, activated protein C resistance (APCR)-Factor V Leiden mutation have recently been a subject of much interest.

Bacterial vaginosis

Polymicrobial infection may be responsible for 5-10% of mid trimester losses. This infection may also be associated with preterm labour and premature rupture of membranes. Other infections (TORCH, Chlamydia) are usually non -recurrent – so no need for routine repeated checks.

Uterine anomalies

Uterine anomalies account for less than 5% of mid trimester losses. Uterine septum commonest Hysteroscopy/Hycosy preferred over HSG (hysterosalpingogram) to detect septae, adhesions, cervical length and patency, Laparoscopic guided hysteroscopic resection may be needed in certain cases.

Cervical incompetence

Cervical Incompetence can often be difficult to diagnose. A careful clinical history and preconceptual cervical length/patency assessment is needed before deciding on cervical cerclage (Cervical Stitch).

Nutrition/Environmental factors

Excessive consumption of coffee, smoking, alcohol, selenium deficiency has all been associated with spontaneous miscarriage. Maternal diseases such as diabetes and thyroid disorders may have an increased risk for recurrent loss. However, routine screening for diabetes or thyroid disease is not needed in asymptomatic women with recurrent miscarriage.

Nitu Bajekal (Consultant Gynaecologist) (Updated Feb 2009)