Habitual abortion, recurrent miscarriage or recurrent pregnancy loss (RPL) is the occurrence of repeated (three or more consecutive) pregnancies that end in miscarriage of the fetus, usually before 20 weeks of gestation. RPL affects about 0.34% of women who conceive.
The majority (85%) of women who have had two miscarriages will conceive and carry normally afterwards
There are various causes for habitual abortions, and some are treatable. Some couples never have a cause identified, often after extensive investigations.
A) Anatomical conditions
A uterine malformation is considered to cause about 15% of recurrent miscarriages. The most common abnormality is a uterine septum, a partition of the uterine cavity. The diagnosis is made by MRI or a combined Laparoscopy and Hysteroscopy of the uterus. Also uterine leiomyoma (fibroid) could result in pregnancy loss.
In the second trimester a weak cervix can become a recurrent problem. Such cervical incompetence leads to premature pregnancy loss resulting in miscarriages or preterm deliveries.
B) Chromosomal disorders
This can cause a spontaneous miscarriage if there are chromosomal abnormalities in female or the male partner.
C) Endocrine disorders
Women with thyroid disorders, both hypo- and hyperactivity, have are at increased risk for pregnancy losses. Unrecognized or poorly treated diabetes mellitus leads to increased miscarriages. Women with Polycystic ovary syndrome also have higher rates of miscarriages due to increased level of Insulin and androgens (male hormones).
Progesterone deficiency may also lead to miscarriages- all the above are easily corrected although diagnosis is essential.
An important example is the possible increased risk of abortion in women with thrombophilia (propensity for blood clots). The most common problem is the Leiden. Treated with anticoagulant medication and aspirin.
E) Immune factors
Antiphospholipid syndrome e.g.: SLE (Systemic lupus erythematosis) also a very important cause of Infertility
Antiphospholipid syndrome (APS) is an autoimmune disorder characterized by arterial and venous thrombosis, adverse pregnancy outcomes (for mother and fetus), and raised levels of Antiphospholipid (APL) antibodies.
The APL antibody syndrome is present if at least one of the clinical criteria and one of the laboratory criteria are present.
Vascular thrombosis: one or more episodes of arterial, venous or small vessel thrombosis.
Pregnancy morbidity: at least one unexplained death of a normal-appearance fetus at or beyond the 10th week of gestation; at least one preterm birth of a neonate of normal appearance before 34 weeks of gestation, because of eclampsia or severe pre-eclampsia or with signs of placental insufficiency
Three or more unexplained consecutive spontaneous miscarriages before 10 weeks of gestation where anatomical, hormonal and chromosomal causes have been excluded.
Lupus anticoagulant (LA) is present in the woman's plasma, on two or more occasions at least 12 weeks apart.
Anticardiolipin (ACL) antibody is present in serum or plasma, in medium or high titre (ie ≥40 GPL units or MPL units or ≥99th centile), on two or more occasions at least 12 weeks apart.
In systemic lupus erythematosus (SLE) 30% have APL antibodies.
APS occurs most commonly in young women of fertile age - male:female 1:3.5.
The condition accounts for about 20% of recurrent thrombosis in young people and 15% of cases of recurrent fetal loss.
Young adults (≤50 years old) with ischaemic stroke and women with recurrent pregnancy loss (≥3 pregnancy losses) before 10 weeks of gestation should be screened for APL antibodies.
Levels of aCL, anti-beta2 GPI or lupus anticoagulant (LA) on two occasions at least 12 weeks apart.
FBC; thrombocytopenia, haemolytic anaemia.
CT scanning or MRI of the brain (cerebrovascular accident), chest (pulmonary embolism) or abdomen (Budd-Chiari syndrome).
A healthy lifestyle in line with prevention of cardiovascular disease is recommended:
Take regular physical exercise.
Maintain a healthy diet and avoid overweight/obesity.
Avoid excessive alcohol intake.
Adequate management of cardiovascular risk factors, including diabetes, hypertension and hyperlipidaemia.
APS in pregnancy may affect both mother and fetus throughout the entire pregnancy and is associated with high morbidity. Clinical complications are variable and include recurrent miscarriage, stillbirth, IUGR and pre-eclampsia.
For women with APS with recurrent (≥3) pregnancy loss, antenatal administration of low molecular weight heparin combined with low-dose aspirin is recommended throughout pregnancy.
Treatment should begin as soon as pregnancy is confirmed.
For women with APS and a history of pre-eclampsia or IUGR, low-dose aspirin is recommended.
Women with APL antibodies should be considered for postpartum thromboprophylaxis.
F) Ovarian factors
The risk for miscarriage increases with age, and women in the advanced reproductive age who have a reduced ovarian reserve are prone to higher risk of repeated miscarriages due to decreased egg quality.
A number of maternal infections can lead to a single pregnancy loss, including listeriosis, toxoplasmosis, and certain viral infections (rubella, herpes simplex, measles, cytomegalo virus, coxsackie virus). These need to be first confirmed by TORCH screening prior to treatment.
Transvaginal ultrasonography is very important in early pregnancy to asses the baby. Parental chromosome testing (karyogram) is generally recommended after 2 or 3 pregnancy losses. Blood tests for thrombophilia, ovarian function, thyroid function and diabetes are performed.
If the likely cause of recurrent pregnancy loss can be determined treatment is to be directed accordingly. In patients with unexplained RPL chances are about 60-70% that the next pregnancy is successful without treatment. In certain chromosomal situations, while treatment may not be available, IVF with Preimplantation genetic diagnosis (PGD) may be able to identify embryos with a reduced risk of another pregnancy loss which then would be transferred.