Miscarriages (Spontaneous Abortion) — Definition and Therapy

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Image: “Human Embryo – Approximately 8 weeks estimated gestational age” by lunar caustic. License: CC BY 2.0

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Introduction

Abortion describes a pregnancy that ends before the viability of the fetus. With a prevalence of 10–20%, abortions are very frequent. The vital signs of the child are important in the context of the different forms of abortion.

Note: A typical symptom of spontaneous abortions is vaginal bleeding.

Imminent Abortion

Imminent abortion is generally reversible. Typically, patients present with vaginal bleeding and a closed uterine orifice.

The pregnancy is still intact and infant heart sounds are still detectable. Therapy could involve physical rest with the administration of magnesium.

Missed Abortion

This is a form of abortion that mostly has an asymptomatic course. Usually, the diagnosis is made during routine examinations. Here, no infant heart sounds can be heard. Curettage is the first-line therapy.

Incipient Abortion

This corresponds to a developing miscarriage. The uterine orifice is already opened due to labor. Typical symptoms are vaginal bleeding with pain in the lower abdomen and absent infant heart sounds. First-line therapy is also curettage.

Incomplete Abortion

Here, parts of the trophoblast are already shed. The uterine orifice is completely open and infant heart sounds are undetectable. The patient often experiences severe vaginal bleeding with pain in the lower abdomen. In this case, intervention is also still necessary to remove the necrotic trophoblast.

Complete Abortion

In this type of abortion, the embryo is already completely shed, therefore curettage is not necessary. Clinically, the uterus is rather small and hardened. The vaginal bleeding usually ceases.

Habitual Abortion

Three or more consecutive spontaneous abortions are characteristic of habitual abortion. Etiologically, different factors can play a role, e.g., genetic changes with regard to chromosome aberrations. Mostly, these are balanced translocations.

The polycystic ovarian syndrome can be another cause since follicle maturation is disturbed in this case. Furthermore, anatomic changes can lead to spontaneous abortions. Occasionally, immunological causes also play a role in the context of habitual abortions. Frequently, an antiphospholipid syndrome is present, in which thromboembolic events occur from roughly the 2nd trimester onward and cause the miscarriage.

After extensive diagnostics, the cause of habitual abortions is usually found. Therapeutically, the patients are then treated causally, e.g., with surgical correction of uterine anomalies or with immunological therapy if antiphospholipid antibodies are present.

Therapy for Abortions and Miscarriages

For therapy, cerclage, tocolysis, and lung maturation induction can be considered, in addition to curettage. Curettage is the first-line therapy in case of precocious pregnancies. Curettage implies the scraping of the uterine cavity, where the cavity is scraped up to the superficial mucosa.

If the pregnancy is already progressed and is already in the 24th week or more, tocolysis and lung maturation induction can be performed since the child is considered viable in this situation. Tocolysis is the inhibition of labor. It can occur via medication with sympathomimetic β2 agonists (e.g., fenoterol) or magnesium sulfate.

Lung maturation induction occurs via glucocorticoids. In 24 h intervals, 12 mg of betamethasone or sympathomimetic β2 agonists are injected twice. These measures induce the surfactant production of the pneumocytes and, thus, prevent respiratory distress syndrome in the child.

After repeated spontaneous abortions and imminent cervical insufficiency, cerclage can become necessary. In this procedure, the physician tries to form the internal orifice of the uterus and keep it together via absorbable threads.