Recurrent pregnancy loss: causes and work-up
Losing a pregnancy is painful; losing several is deeply traumatic. Many couples feel that “something must be wrong” and ask for exhaustive testing.
The truth is gentler than they fear: in most cases, the prognosis for a future successful pregnancy remains good. A correct, targeted work-up is more useful than an excessive one.
What is defined as recurrent loss?
This definition recognizes that a couple with two losses deserves care and answers, without having to wait for a third.
How common is it?
A single miscarriage is common: it affects about one in five recognized pregnancies. Recurrent losses are much rarer, affecting a small proportion of couples.
It is important to remember that, even after several losses, most women eventually have a baby.
What are the causes?
Established causes include embryonic chromosomal abnormalities (the commonest cause of a single miscarriage), antiphospholipid syndrome, certain anatomical uterine abnormalities, and endocrine disorders such as uncontrolled hypothyroidism or diabetes.
Despite a full work-up, in about half of cases no clear cause is found (unexplained recurrent loss). This, though frustrating, carries a relatively good prognosis.
Which work-up is recommended?
The evidence-based work-up includes: testing for antiphospholipid syndrome (antibodies), thyroid function, imaging of the uterine cavity (ultrasound, possibly 3D or hysteroscopy), and in selected cases parental karyotype or genetic analysis of the pregnancy tissue.
The 2022 update added assessment for adenomyosis as a newer element in evaluating women with recurrent loss.
Which tests are NOT needed routinely?
Many widely offered tests are not recommended routinely, because they do not change management or have not been shown to be useful: testing for inherited thrombophilia outside specific indications, measuring “NK cells”, and various immunological tests.
Overtesting can lead to needless anxiety and to treatments without benefit. A good work-up is targeted, not exhaustive.
Which treatments have benefit?
Where a specific cause is found, treatment targets it: in antiphospholipid syndrome, the combination of low-dose aspirin and heparin improves outcomes; in hypothyroidism, restoring thyroid function; in anatomical abnormalities, appropriate surgical correction where indicated.
In unexplained cases, progesterone may be considered in women with early-pregnancy bleeding and a history of previous losses. Above all, supportive care and close monitoring of the next pregnancy have real value.
What is the prognosis?
The prognosis is, in most cases, encouraging. Even when no cause is found, the majority of couples with recurrent loss eventually achieve a successful pregnancy, especially with close monitoring and support.
The woman’s age and the number of previous losses influence the prognosis, but hope remains realistic.
Summary
Recurrent loss is defined by ESHRE (2022) as two or more losses, and warrants a targeted work-up: antiphospholipid syndrome, thyroid, uterine anatomy and, selectively, genetic testing. Many widely offered tests (routine inherited thrombophilia, NK cells) are not recommended. Treatment targets the cause where one exists. Most importantly: even without a clear cause, the prognosis for a future baby remains good.
Sources: ESHRE, “Guideline: recurrent pregnancy loss — an update in 2022”, Hum Reprod Open 2023.
⚕ Medically reviewed by Prof. Stratis Kolibianakis · Thessaloniki Medical Association Reg. No. 16340
ARTICLE 8 · RECURRENT LOSS & FAILURE
