ED: Recurrent miscarriage can be devastating for some couples who may have invested many years, multiple cycles of IVF and thousands of dollars in trying to have a child of their own.
Miscarriage is defined as the loss of a pregnancy before 24 weeks. Recurrent miscarriage (RM) is the loss of two or more pregnancies in Australia and effects 5% of couples. In certain European countries, RM is defined as three or more consecutive pregnancy losses. Despite exhaustive investigations, over 50% of cases reveal no aetiology or pathological reason for RM with disappointment and frustration for patients and clinician.
The main risk factors are maternal age (risk of aneuploidy in oocytes for women less than 35 is 10%, whereas 40-44yrs is 50%) and prior miscarriages. After two miscarriages the chance of livebirth is 70% within two years. After three miscarriages the incidence of further miscarriage increases exponentially.
Investigations are pelvic ultrasound scan, blood tests (Antiphospholipid antibodies, FSH, LH, estrogen, progesterone, AMH, FBC, TSH, fasting insulin/glucose, thrombophilia screen, parental karyotype) and cytogenetics on products of conception.
Causes and treatment
Antiphospholipid syndrome is found in 15-20% of women with RM and is the most treatable cause. Treat with Aspirin 150mg and Clexane 40mg daily pregnancy during pregnancy then Clexane alone until six weeks post-partum. Inherited thrombophilia (Factor V Leiden mutation, protein C or S deficiency) account for 15% of causes of RM. Treatment options include Clexane or Aspirin daily although Cochrane review of nine studies showed minimal benefits.
Genetic factors cause of 2-5% of RM. Referral to a Clinical geneticist is recommended. A balanced reciprocal or Robertsonian translocation is the most common karyotype anomaly in the parents (85%).
Maternal diabetes (if poorly controlled) increases risk of RM together with congenital malformations. In hypothyroidism utilise thyroxine if TSH above 2.5. If progesterone is low in first trimester advise progesterone support tailored to individual patients’ specific clinical requirements.
In uterine malformations (5-10%) such as subseptate, septate and bicornuate uteri, trans cervical hysteroscopic resection techniques (septoplasty) are recommended (generally day procedures).
Fibroids (especially submucous) decrease conceptions by 50% and double miscarriage rates. Removal is recommended. Virtually all pathologies (e.g. polyps adhesions) are treated with either hysteroscopy or laparoscopy.
Cervical incompetence generally preceded by spontaneous rupture of membranes or painless dilation of cervix usually 2nd or early 3rd trimester. Risk factors include prior cone biopsy, LLETZ or cervical length under 25 mm before 24 weeks of pregnancy.
Treatment traditionally involved a MacDonald vaginal cervical cerclage, however if it is not possible to place vaginally (secondary to short/deformed cervix) or prior failed vaginal cerclage, then a laparoscopic supra cervical cerclage can be placed. This is a relatively simple day case procedure allowing placement of the suture ‘higher’ at the cervico-isthmic junction.
The suture is left in situ indefinitely and all deliveries require Caesarean section.
Key Messages
- Following a diagnosis of RM live births can occur in around 70% of women
- Increasing maternal age and more than three miscarriages worsens prognosis.
- A cause is identified in under 50% of women
References available on request.
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Author competing interests: nil relevant disclosures.
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