Miscarriage Prevention – Causes and Strategies

What Is Miscarriage Prevention?

Miscarriage prevention (also called miscarriage prophylaxis) refers to all preventive measures designed to reduce the risk of pregnancy loss. A miscarriage, medically known as a spontaneous abortion, is defined as the loss of a pregnancy before 24 completed weeks of gestation. Approximately 10–20% of all clinically recognized pregnancies end in spontaneous miscarriage, with the majority occurring during the first trimester (up to 12 weeks). Preventive strategies are relevant both for women with a general desire to conceive and for those at elevated risk, such as women with a history of recurrent miscarriages.

Causes and Risk Factors for Miscarriage

Understanding the most common causes and risk factors is essential for effective prevention:

• Chromosomal abnormalities: The most common cause of first-trimester miscarriages. These are usually random genetic errors occurring during embryonic cell division.
• Hormonal disorders: A deficiency in progesterone (luteal phase deficiency) or thyroid dysfunction (hypothyroidism, hyperthyroidism) can impair the uterine environment necessary for implantation.
• Anatomical factors: Uterine malformations (e.g., uterine septum, bicornuate uterus), fibroids, or polyps can interfere with embryo implantation or growth.
• Immunological factors: Antiphospholipid syndrome (APS) is an autoimmune condition that causes blood clots in placental vessels and is a recognized cause of recurrent pregnancy loss.
• Infections: Certain infections such as toxoplasmosis, listeriosis, and rubella can increase the risk of miscarriage.
• Lifestyle factors: Smoking, excessive alcohol consumption, obesity, severe underweight, and high caffeine intake are modifiable risk factors.
• Maternal age: The risk of miscarriage increases significantly with advancing maternal age, particularly after the age of 35.
• Thrombophilia: Inherited or acquired clotting disorders can compromise placental blood flow.

Diagnostic Workup for Elevated Risk

For women with recurrent pregnancy loss (typically defined as two or more consecutive miscarriages), a thorough diagnostic evaluation is recommended:

• Genetic testing of both partners (karyotype analysis)
• Hormonal profile: thyroid function (TSH, fT3, fT4), progesterone, AMH, FSH, LH, prolactin
• Coagulation screening: ruling out thrombophilia and antiphospholipid antibodies
• Gynecological imaging: ultrasound and, if necessary, hysteroscopy to assess the uterine cavity
• Infection serology when specific pathogens are suspected

Medical Interventions for Miscarriage Prevention

Progesterone Supplementation

In women with confirmed luteal phase deficiency or those with recurrent miscarriage and vaginal bleeding in early pregnancy, progesterone supplementation (vaginal or oral) is commonly prescribed. Clinical evidence, including the PRISM trial, demonstrates a beneficial effect of progesterone in specific patient groups with bleeding in early pregnancy and a history of prior miscarriage.

Treatment of Antiphospholipid Syndrome

Women diagnosed with APS and recurrent pregnancy loss typically receive a combination therapy of low-dose aspirin and low-molecular-weight heparin (LMWH). This regimen improves placental blood flow and reduces the risk of thrombotic events in the placenta.

Thyroid Management

Adequate treatment of hypothyroidism with a target TSH level below 2.5 mIU/l during early pregnancy is considered important, as untreated or undertreated thyroid dysfunction significantly increases the risk of miscarriage. Women with elevated thyroid antibodies (TPO antibodies) require close monitoring even when thyroid hormone levels are within the normal range.

Surgical Correction

Anatomical abnormalities such as a uterine septum can be surgically corrected via hysteroscopy to improve the chances of a successful pregnancy. Relevant fibroids or endometrial polyps may also be removed.

Cervical Cerclage

In women with confirmed cervical insufficiency, a cervical cerclage (surgical suturing of the cervix) can significantly reduce the risk of second-trimester pregnancy loss.

Nutrition and Micronutrients for Miscarriage Prevention

A balanced diet and targeted supplementation play an important supporting role in reducing the risk of pregnancy loss:

• Folic acid: Daily supplementation of 400–800 µg of folic acid before and during early pregnancy is essential for neural tube development and universally recommended. In women with an MTHFR gene variant, the active form (methylfolate) may be more appropriate.
• Vitamin D: Adequate vitamin D levels (25-OH vitamin D) have been associated with a reduced risk of miscarriage. Supplementation is recommended in cases of deficiency.
• Omega-3 fatty acids: DHA and EPA from oily fish or supplements may have anti-inflammatory effects and support placental perfusion.
• Coenzyme Q10, zinc, and selenium: These micronutrients are involved in cell division and protection against oxidative stress and are frequently used in practice, although the evidence base is still emerging.

Lifestyle Measures

In addition to medical therapies, lifestyle modifications have a significant impact on miscarriage risk:

• Smoking cessation: Smoking increases miscarriage risk and should be stopped completely before and during pregnancy.
• Alcohol avoidance: No level of alcohol consumption is considered safe during pregnancy. Even small amounts may increase the risk.
• Healthy body weight: Both obesity and severe underweight are associated with higher miscarriage rates. A body mass index (BMI) within the normal range is recommended.
• Stress reduction: Chronic psychological stress can contribute to hormonal imbalances. Relaxation techniques, yoga, and psychological support may be beneficial.
• Reducing caffeine intake: A daily caffeine intake exceeding 200 mg (approximately 2 cups of coffee) has been linked to an increased risk of miscarriage.

Psychological Support

Recurrent miscarriages represent a significant emotional burden for affected women and couples. Professional psychological counseling, peer support groups, and dedicated reproductive counseling should be considered as integral parts of a holistic preventive approach. Compassionate, specialized care from reproductive medicine specialists and midwives is an important component of ongoing support.

References

1. Deutsche Gesellschaft fuer Gynaekologie und Geburtshilfe (DGGG): Guideline on Diagnosis and Treatment of Recurrent Spontaneous Abortion, AWMF Register No. 015-050, 2022.
2. Coomarasamy A et al. - A Randomized Trial of Progesterone in Women with Bleeding in Early Pregnancy. New England Journal of Medicine, 2019; 380: 1815-1824.
3. ESHRE Guideline Group on RPL - ESHRE Guideline: Recurrent Pregnancy Loss. Human Reproduction Open, 2023; hoad002.