Recurrent Pregnancy Loss — Symptoms, Causes & Treatment | MyMedicPlus

Recurrent pregnancy loss (RPL) is defined as 2 or more consecutive pregnancy losses before 20 weeks of gestation (RCOG and ESHRE definition — some UK and European guidelines use 2 consecutive losses; ASRM previously used 3, now also accepts 2 or more). It affects approximately 1–2% of couples trying to conceive. An identifiable cause is found in approximately 50% of cases; the remainder are classified as unexplained RPL. Chromosomal abnormalities of the embryo account for the majority of individual early pregnancy losses (50–60% of all spontaneous miscarriages under 12 weeks), but parental chromosomal factors, uterine structural anomalies, antiphospholipid syndrome, and thrombophilias are more important causes in recurrent rather than isolated loss. The risk of a further loss after 2 consecutive losses is approximately 25–30%; after 3 consecutive losses, approximately 35–40% — these statistics improve significantly with specialist management. Specialist evaluation is recommended after 2 consecutive pregnancy losses; waiting for a third loss before investigation causes unnecessary emotional harm and delays potentially curative treatment. The psychological impact of RPL is profound — depression and anxiety are near-universal, and dedicated psychological support within an RPL clinic is integral to holistic care.

Chromosomal abnormalities in the embryo account for 50–60% of individual early pregnancy losses; however, in recurrent loss, parental chromosomal factors are detected in 3–5% (balanced translocations — carrier parents produce aneuploid gametes at high frequency, causing repeated chromosomally abnormal pregnancies; identified by parental karyotype). Uterine structural anomalies: septate uterus (partial or complete uterine septum — the most common correctable structural cause, found in 10–15% of RPL — the fibrovascular septum has poor implantation quality and inadequate blood supply); submucosal fibroids distorting the uterine cavity; intrauterine adhesions (Asherman's syndrome); and arcuate or bicornuate uterus (debated significance). Antiphospholipid syndrome (APS): the most important acquired thrombotic cause — antibodies (anticardiolipin, anti-beta-2 glycoprotein I, lupus anticoagulant) cause thrombosis in placental vasculature and impair implantation; found in 15–20% of RPL patients; the only RPL cause with a proven effective treatment (aspirin + LMWH). Inherited thrombophilias (factor V Leiden, prothrombin G20210A, protein C/S deficiency): associated with second-trimester losses but evidence for treatment is limited. Thyroid dysfunction: hypothyroidism and thyroid autoimmunity (positive TPO antibodies) are associated with RPL — TSH above 2.5 mIU/L associated with higher RPL rates. Advanced maternal age (above 35): increases aneuploidy rate in embryos substantially. Poorly controlled diabetes (HbA1c above 48 mmol/mol) and obesity (BMI above 30) are modifiable risk factors.

Recurrent episodes of vaginal bleeding (ranging from light spotting to heavy haemorrhage) and uterine cramping in early pregnancy, followed by passage of products of conception (tissue, clots, and fluid). Most RPL occurs in the first trimester (before 12 weeks), though antiphospholipid syndrome and thrombophilias more commonly cause second-trimester losses (12–20 weeks), which may involve more advanced fetal development and carry a more traumatic clinical experience. Between pregnancies, patients experience significant and cumulative psychological distress: grief and bereavement (recognised as pregnancy loss regardless of gestation), anticipatory anxiety in subsequent pregnancies (particularly at the gestation where previous losses occurred), depression (40–60% of women after 3 or more losses), relationship strain, social withdrawal, loss of confidence in the body's ability to carry a pregnancy, and occupational disruption. A small proportion of women experience severe anxiety in subsequent pregnancies that may require specialist perinatal mental health input. These psychological features are core clinical concerns in RPL management and should be actively assessed and supported throughout care.

Investigations (RCOG Guideline Green-top 17 and ESHRE RPL guideline 2022) should begin after 2 consecutive losses: Parental karyotype (peripheral blood chromosomal analysis): detects balanced translocations in 3–5% of RPL couples — identifies couples at high risk of aneuploid pregnancies who benefit from PGT-SR (preimplantation genetic testing for structural rearrangements). Uterine structural evaluation: 3D saline infusion sonography (SIS) or 3D transvaginal ultrasound is the first-line imaging investigation — highly accurate for detecting uterine septum, fibroids, and intrauterine adhesions; diagnostic hysteroscopy is the gold standard and allows simultaneous treatment (septal resection, adhesiolysis). Antiphospholipid antibodies: anticardiolipin IgG/IgM (above 40 GPL or MPL units or above the 99th percentile), anti-beta-2 glycoprotein I IgG/IgM, and lupus anticoagulant — must be positive on two separate tests at least 12 weeks apart to confirm APS diagnosis (transient antibodies after infection can be positive on a single test). Thyroid function tests: TSH and free T4; thyroid peroxidase antibody (TPO Ab) — evidence for treating euthyroid women with positive TPO Ab is debated (TABLET trial showed no benefit from levothyroxine, but many clinics maintain TSH below 2.5 mIU/L). Thrombophilia screen: factor V Leiden, prothrombin G20210A mutation, protein C and S, antithrombin III. HbA1c (diabetes), and BMI and lifestyle assessment.

Antiphospholipid syndrome (APS — the most treatable cause): low-dose aspirin 75 mg daily (started pre-conception) combined with low-molecular-weight heparin (LMWH — enoxaparin 40 mg SC daily from positive pregnancy test to 34 weeks) reduces pregnancy loss rate from approximately 80–90% to 25–30% in confirmed APS (PROMISE and supporting trials). Uterine septum: hysteroscopic metroplasty (resection of the fibrovascular septum under hysteroscopic guidance) — observational data show improved live birth rates; randomised data from TRUST trial are inconclusive but hysteroscopy is widely offered given the minimal risk and surgical simplicity. Intrauterine adhesions (Asherman's syndrome): hysteroscopic adhesiolysis followed by hormonal treatment (oestrogen for endometrial regeneration) and post-operative progesterone. Progesterone supplementation: vaginal progesterone (Cyclogest 400 mg twice daily from positive pregnancy test to 12 weeks) — the PRISM trial (n=4,153) demonstrated a statistically significant increase in live birth rate in women with prior RPL and early pregnancy vaginal bleeding (72% vs 67% in placebo). Chromosomal causes: IVF with preimplantation genetic testing for aneuploidies (PGT-A) reduces per-transfer miscarriage rate but cumulative live birth rate benefits are debated versus expectant management. PGT-SR (structural rearrangements) benefits couples with balanced translocations. Thyroid: levothyroxine to maintain TSH below 2.5 mIU/L in hypothyroid women; treatment of euthyroid TPO-positive women remains debated. Unexplained RPL: supportive care with regular early pregnancy ultrasound, progesterone, and psychological support achieves 70–80% live birth rates.

Psychological complications are significant and often underacknowledged: grief and bereavement, depression (affecting approximately 40–60% of women after 3 or more losses), anxiety (including severe anticipatory anxiety in subsequent pregnancies), PTSD symptoms (hypervigilance, intrusive thoughts, avoidance of reminders of loss), relationship strain (partners experience grief differently and may struggle to provide adequate support), sexual dysfunction, and social withdrawal are common and require proactive clinical attention. APS untreated carries risks beyond early pregnancy loss: late pregnancy complications including second-trimester loss, pre-eclampsia, severe IUGR, placental abruption, and placental insufficiency from thrombosis of the uteroplacental circulation — all requiring expert obstetric management in subsequent pregnancies. Medical complications of miscarriage in the RPL context: retained products of conception (RPOC) causing haemorrhage or infection, septic miscarriage, and intrauterine adhesion formation (Asherman's syndrome) from repeated surgical evacuations — preventing adhesion formation requires minimising surgical intervention and considering medical management. Future pregnancies in RPL patients require: enhanced surveillance from 6 weeks with fortnightly ultrasound scan, aspirin + LMWH where indicated, and psychological support throughout. Despite RPL, the cumulative live birth rate remains good — approximately 65–75% of women with unexplained RPL will have a successful subsequent pregnancy.

Optimise preconception health: achieve healthy BMI below 30 (obesity is associated with 30–40% higher RPL risk — weight loss improves outcomes and response to treatment); control thyroid disease (target TSH below 2.5 mIU/L for all women with RPL); control diabetes (HbA1c below 48 mmol/mol before conception — hyperglycaemia significantly increases miscarriage risk); take folic acid 400 mcg daily from pre-conception (5 mg for women on antiepileptics, with prior NTD, or BMI above 30); avoid smoking (increases RPL and aneuploidy risk) and alcohol (abstinence recommended in early pregnancy). Treat all identified causes before next pregnancy attempt: initiate aspirin before next conception in confirmed APS; complete any hysteroscopic uterine surgery and confirm normal cavity on post-operative ultrasound before next conception. Offer psychological support throughout: dedicated nurse counsellors or psychologists within an RPL clinic, peer support groups, and cognitive behavioural therapy significantly improve wellbeing and coping. Vitamin D supplementation (1,000–2,000 IU daily) and achieving vitamin D sufficiency (25-OH vitamin D above 50 nmol/L) is safe and has emerging associations with improved pregnancy outcomes. RPL clinics providing specialist monitoring with early ultrasound surveillance, dedicated nursing support, and psychological care significantly improve live birth rates — even in unexplained RPL, achieving 65–80% live birth rates.

Call emergency services (999/911) or attend Emergency Department immediately for: heavy vaginal bleeding in early pregnancy soaking more than one pad per hour — haemorrhage from miscarriage, which may require surgical management (ERPC — evacuation of retained products of conception) or medical treatment; severe one-sided pelvic pain with vaginal bleeding in early pregnancy — suspected ectopic pregnancy (implantation outside the uterus, usually in the fallopian tube) — a life-threatening emergency requiring immediate surgical or medical (methotrexate) management; faintness, dizziness, or collapse alongside abdominal pain in early pregnancy — possible ruptured ectopic pregnancy with haemoperitoneum. See your GP or EPU (Early Pregnancy Unit) urgently for: any vaginal bleeding in a confirmed early pregnancy — an urgent transvaginal ultrasound and beta-hCG measurement will assess pregnancy viability; shoulder tip pain with early pregnancy pain — referred diaphragmatic irritation from ruptured ectopic; positive pregnancy test with a history of previous ectopic pregnancy — requires early scan at 6 weeks to confirm intrauterine location. After 2 confirmed losses: ask for referral to a recurrent pregnancy loss clinic — do not wait for a third loss; ESHRE and RCOG both support investigation after 2 consecutive pregnancy losses; specialist clinics can identify antiphospholipid syndrome, parental chromosomal translocations, uterine anomalies, and other treatable causes.