Recurrent Miscarriage
Written 8th February 2020 - Last Update 12th July 2026
Recurrent Miscarriage
Recurrent miscarriage = 2 or more intrauterine pregnancy losses up to 20 weeks (consecutive or not) — not 3. All losses must be confirmed intrauterine (not ectopic). This 2-loss threshold is now RANZCOG’s own position (previously ESHRE-only).
Screening tests — what’s actually recommended
The old “day-3 hormone panel” (oestradiol, LH, FSH, free androgen index, SHBG) is no longer supported — most of it is now explicitly not routinely recommended. Current approach:
| Test | Recommendation |
|---|---|
| Lupus anticoagulant, anticardiolipin antibodies (IgG/IgM) | Routine |
| Anti-B2GPI | Case-by-case |
| 3D pelvic ultrasound | Routine |
| TSH, TPO antibodies, thyroid function | Routine |
| Parental peripheral blood karyotype | Case-by-case (if pregnancy tissue analysis unavailable) |
| Sperm DNA fragmentation | Case-by-case (diagnostic only — limited evidence for treatment benefit) |
| ANA antibodies | Case-by-case (diagnostic only) |
| HLA, cytokine, NK cell testing | Not recommended |
| Inherited thrombophilia (Factor V Leiden, prothrombin gene mutation, protein S/C, antithrombin, MTHFR) | Not routinely recommended — reserve for additional thrombophilia risk factors or research context; LMWH does not improve live birth in confirmed inherited thrombophilia |
| PCOS work-up (fasting insulin/glucose) | Not recommended |
| Prolactin | Not routinely recommended |
| Ovarian reserve testing (AMH) | Not recommended |
| Androgen testing | Not recommended |
| Vitamin D | Not recommended |
| LH | Not recommended |
| Homocysteine | Not recommended |
Cytogenetic analysis of pregnancy tissue is not routinely recommended — genetic abnormalities occur less often in recurrent than sporadic miscarriage and rarely change management; discuss the pros/cons of testing with the couple first (some, e.g. Māori, may prefer not to test at all).
Causes and management by category
Antiphospholipid syndrome: confirmed APS + recurrent miscarriage → offer low-dose aspirin (75–150mg/day) from before conception or a positive test, plus low-molecular-weight heparin from a positive test until at least 34 weeks (stop before birth). This combination substantially improves live birth rate over aspirin alone.
Genetic/chromosomal: balanced parental translocation → discuss natural conception vs IVF + PGT-SR. No known genetic cause → IVF alone does not improve outcomes; PGT-A can be considered if IVF is being pursued for other reasons, but evidence for it improving live birth is very uncertain. Offer genetic counselling for an abnormal parental karyotype or a chromosomal anomaly found in pregnancy tissue.
Uterine anatomical factors: septum resection is not recommended, with or without RPL — evidence doesn’t support it improving live birth, miscarriage, or preterm birth rates over expectant management. This is a significant change from older practice assumptions. Surgery for other congenital anomalies (arcuate, unicornuate, bicornuate, didelphys), caesarean-scar-niche resection, hysteroscopic adhesiolysis, and polypectomy/myomectomy of submucosal fibroids are all similarly not routinely recommended — consider case-by-case only if there are additional symptoms (pain, abnormal bleeding) alongside patient preference.
Hypothyroidism:
- Overt hypothyroidism: treat with levothyroxine — strongly recommended, improves miscarriage rate.
- Subclinical hypothyroidism (including mild, TSH >2.5): insufficient evidence to recommend levothyroxine.
- TSH ≤2.5 with positive thyroid antibodies (TPOAb+): levothyroxine should not be offered — no benefit shown.
- If untreated (subclinical or TPOAb+), check TSH again in early pregnancy (7–9 weeks) and monitor as indicated.
Intravenous immunoglobulin (IVIg): not recommended as routine treatment for unexplained recurrent miscarriage — no benefit at moderate dose. A narrow exception: high-dose IVIg (0.4g/kg daily for 5 days, pre-conception or at 4–6 weeks) may improve live birth specifically in women with ≥4 unexplained losses. IVIg for this indication is not funded or supplied by the NZ Blood Service or the Australian National Blood Authority — cost and access are real barriers, and use also competes with IVIg’s established roles (ITP, Kawasaki disease, Guillain-Barré, lupus).
Progesterone: see Miscarriage — recommended only for 2+ losses with current bleeding (vaginal micronised progesterone 400mg BD to 16 weeks), not for asymptomatic RPL.
When pregnant again
- Serial β-hCG 48h apart to confirm an appropriate rise; sub-optimal rise or plateau → consider ectopic or miscarriage.
- Refer for routine antenatal care flagging the RPL history — a dedicated recurrent miscarriage clinic (regular early scans, consistent care) is ideal where available, but not always feasible (particularly rural/remote).