Pregnancy loss and recurrent miscarriage

Spontaneous pregnancy loss and preterm birth are different clinical situations requiring different assessment. The boundary between miscarriage and stillbirth depends on the definition and reporting system used; birth before 37 completed weeks is preterm. ESHRE considers recurrent pregnancy loss after two or more losses, which need not be consecutive. Some guidelines use other criteria, so investigation timing is individualized.

Most miscarriages occur in the first trimester. They are not a universal maternal “rejection” response and are usually not caused by anything the woman did. Even after investigation, recurrent loss often remains unexplained; this does not mean a successful pregnancy is impossible.

Chromosomal and genetic causes

About half of early losses involve embryonic chromosome abnormalities. These include trisomies, monosomy X, triploidy, tetraploidy and other changes. They often arise for the first time rather than being inherited. In a small proportion of couples, one partner carries a balanced rearrangement, such as a translocation, which can produce an unbalanced embryonic chromosome complement.

Testing pregnancy tissue and parental karyotyping are selected according to history and findings, rather than offered to every couple before conception. Genetic counseling helps choose a method and explain its limits. Chorionic villus sampling and amniocentesis are diagnostic procedures used when indicated in an ongoing pregnancy, not mandatory tests after every miscarriage.

Antiphospholipid syndrome and coagulation

Antiphospholipid syndrome (APS) is a recognized cause of some recurrent losses. Tests include lupus anticoagulant, anticardiolipin and anti-β2-glycoprotein I antibodies. Diagnosis requires appropriate clinical features and persistent laboratory abnormalities; positive antibodies are confirmed at least 12 weeks later. One result does not establish APS.

Inherited thrombophilia must not be treated as the main cause of all miscarriages. Routine coagulation gene panels, MTHFR, homocysteine, D-dimer and anticoagulant protein testing are not recommended as a universal investigation for recurrent early loss. Selected tests may be appropriate with a personal or family history of thrombosis. Aspirin and heparin should not be self-started because of a polymorphism; confirmed APS requires a specialist treatment plan.

Hormonal and metabolic disorders

Untreated thyroid disease and poorly controlled diabetes can increase risk. Thyroid function is assessed in recurrent loss; additional tests, such as prolactin or glucose assessment, depend on history and symptoms.

It is incorrect to attribute most early miscarriages to “corpus luteum insufficiency” or high androgens. A routine full LH, FSH, PRL, estradiol, progesterone, DHEA-S and testosterone profile does not establish the cause in every woman. Progesterone indications depend on the clinical situation rather than one low result.

Infection and immune investigations

Some infections can complicate pregnancy, but chronic urogenital infections are not established as the leading cause of all recurrent early losses. Infection testing follows symptoms, risk and pregnancy care standards. Routine TORCH panels, Ureaplasma testing and treatment of every positive antibody result are not universal miscarriage prevention.

Beyond appropriate APS assessment, broad testing for “immune rejection,” NK cells, cytokines or HLA compatibility is not recommended for routine recurrent-loss care outside research.

Uterine anatomy and the cervix

A uterine septum, intrauterine adhesions and some cavity-distorting lesions may matter. Ultrasound is usually the starting point, with further imaging when needed. Not every anatomical finding requires surgery; expected benefit and risks are discussed individually.

Cervical insufficiency means inability of the cervix to maintain pregnancy, usually presenting as painless second-trimester dilation. It is not always caused by injury and does not necessarily begin with fluid leakage. Management depends on history, cervical length and examination; cerclage or other measures require specific indications.

Planning care

Assessment includes a detailed couple’s history, supportive counseling and targeted tests. Avoiding smoking and alcohol, an appropriate weight, folic acid and chronic disease control are important. Not every loss can be prevented; contraception or avoidance of abortion is not treatment for recurrent miscarriage. Heavy bleeding, severe pain, fainting or fever in pregnancy requires urgent medical care.