Recurrent Miscarriage

Recurrent miscarriage is the loss of 3 or more consecutive pregnancies before 24 weeks. Causes include antiphospholipid syndrome, parental chromosomal rearrangement, uterine anomalies, thyroid disease, diabetes and, in many couples, no cause is found. It matters because a treatable cause is found in some couples, and anticoagulation for antiphospholipid syndrome can improve live birth rates.

• Risk rises with maternal age above 35 years.
• Smoking, alcohol, obesity and caffeine above 200 mg daily add risk.
• The chance of a live birth is high in unexplained cases.

The history shows 3 or more pregnancy losses, often at a consistent gestation. Check for features of thyroid disease, diabetes, lupus, venous thrombosis, and uterine symptoms.

• Losses before 10 weeks suggest chromosomal causes; losses after 10 weeks suggest antiphospholipid syndrome, uterine anomaly or cervical weakness.
• Painless mid-trimester dilatation suggests cervical insufficiency.
• Differential diagnosis: sporadic miscarriage, antiphospholipid syndrome, cervical insufficiency, uterine septum, parental translocation, thyroid disease, diabetes, systemic lupus erythematosus.
• Complications: psychological morbidity, anaemia, repeated surgical evacuation, uterine adhesions, preterm birth in later pregnancy.

The approach is to confirm the number and gestations of losses and test for treatable causes.

• Antiphospholipid antibodies: lupus anticoagulant, anticardiolipin IgG and IgM, anti beta 2 glycoprotein I; repeat after 12 weeks if positive.
• TSH, HbA1c or fasting glucose, full blood count.
• Parental karyotype where available; karyotype of products of conception if a loss recurs.
• Pelvic ultrasound, preferably three dimensional, or hysterosalpingography or saline sonography for uterine septum, fibroids or adhesions.
• Cervical length in the second trimester for painless mid-trimester losses.

Treat the cause found and give supportive care in the next pregnancy.

• Supportive: stop smoking and alcohol; limit caffeine to 200 mg daily; achieve a body mass index of 18.5 to 25; early pregnancy unit access with scans from 6 weeks; emotional support.
• Pharmacological: folic acid 400 micrograms oral daily before conception and to 12 weeks (5 mg if diabetic or on antiepileptics); for antiphospholipid syndrome give aspirin 75 mg oral daily from conception plus enoxaparin 40 mg subcutaneous daily from a positive pregnancy test to 6 weeks postpartum; for hypothyroidism give levothyroxine to keep TSH between 0.4 and 2.5 mIU/L; for diabetes keep HbA1c below 6.5 percent; for women with early bleeding and at least one previous miscarriage give micronised progesterone 400 mg vaginally twice daily from the positive test to 16 weeks.
• Procedures: hysteroscopic resection of uterine septum; cervical cerclage at 12 to 14 weeks for painless mid-trimester loss or cervical length below 25 mm before 24 weeks.
• Special groups: antiphospholipid syndrome with previous thrombosis requires enoxaparin 1 mg/kg subcutaneous 12-hourly in pregnancy.
• Red flags: bleeding, severe pain, leg swelling, chest pain, breathlessness.
• Follow-up: pre-conception clinic; early scan at 6 weeks; growth scans at 28, 32 and 36 weeks in antiphospholipid syndrome; review at 6 weeks postpartum.