Schwangerschaft

Pregnancy risk factors and miscarriage: an overview

Fehlgeburt Frau Trauer


Key Takeaways

  • Would you like to find out more about which risk factors contribute to a miscarriage?
  • A miscarriage before the 20th week of pregnancy is due to a spontaneous genetic mutation in 45% of cases and could not have been prevented in these cases.
  • In this article, you can find out which risk factors you can influence and which risks you should have checked by a doctor before or during pregnancy.

Pregnancy is an exciting and emotional time for expectant parents. However, despite advances in medicine, there are still risks that can lead to complications or a miscarriage. Being aware of these risk factors can help to minimize risks. However, miscarriage is often caused by factors that cannot be influenced. Blaming someone in the event of a miscarriage is rarely justified.

What is a miscarriage?

A miscarriage, also known medically as an “abortion” or “spontaneous abortion”, is the loss of a pregnancy before the 20th week of pregnancy. Most miscarriages occur in the first trimester and are often due to genetic abnormalities in the embryo. A distinction is made between early miscarriage (up to the 12th week of pregnancy) and late miscarriage (13th to 22nd week of pregnancy).

The following factors are associated with an increased risk of miscarriage.

1. Maternal age

The age of the mother is one of the most significant risk factors for miscarriage. The risk increases the older the mother is. Women* over 35 years of age have a higher risk because the quality and quantity of eggs decrease with age and genetic abnormalities occur more frequently.

Age of motherRisk of miscarriage
Under 35 years15 %
35-39 years20-25 %
Over 40 years40-50 %

 
2. Previous miscarriages

Women* who have already suffered one or more miscarriages are more prone to a repeat miscarriage. Even if the causes of previous miscarriages can vary greatly, the risk in a subsequent pregnancy increases. In such cases, close monitoring through regular ultrasound examinations is particularly important.

3. Health status and lifestyle

Certain health conditions and lifestyle habits also increase the risk of miscarriage:

  • Chronic diseases: Women* with untreated chronic conditions such as diabetes, high blood pressure, thyroid disease or autoimmune disorders (e.g. lupus) are at increased risk.
  • Overweight and underweight: A body mass index (BMI) above 30 or below 18.5 is associated with a higher risk of miscarriage.
  • Smoking, alcohol and drugs: Smoking and drinking alcohol during pregnancy can affect blood flow to the fetus and increase the risk of miscarriage. Taking illegal drugs also carries significant risks.
  • Caffeine: Consuming more than 300 mg of caffeine a day (about three cups of coffee) can increase the risk of miscarriage.

    4. Infections

    Certain infections can significantly increase the risk of miscarriage because they can affect fetal development:

    • Viral infections: Conditions such as rubella, cytomegalovirus (CMV), and parvovirus can be dangerous during pregnancy.
    • Bacterial infections: Bacterial infections, including bacterial vaginosis and listeriosis, can lead to complications if left untreated.
    • Sexually transmitted diseases: Infections such as chlamydia, gonorrhea or syphilis can increase the risk of miscarriage or premature birth.

      5. Anatomical problems

      Certain anatomical abnormalities can increase the risk of miscarriage. These include:

      • Uterine anomalies: Abnormal uterine shapes or adhesions can increase the risk of miscarriage.
      • Cervical incompetence: A weak cervix, also known as cervical incompetence, can increase the risk of miscarriage in the second trimester.

        6. Genetic abnormalities

        Genetic abnormalities are a common risk, especially in the first trimester. Chromosomal disorders, such as trisomies (e.g. trisomy 21), often lead to miscarriage. These anomalies usually occur randomly, but can also be passed on by genetic factors from parents. A special form of miscarriage caused by genetic changes is the missed abortion, in which the embryo has died but is not expelled.

        7. Environmental factors

        Environmental factors also play a role in pregnancy health:

        • Pollutants: Contact with certain chemicals, pesticides or radiation can increase the risk of miscarriage.
        • Air pollution and passive smoking: Studies show that pregnant women* who live in heavily polluted areas or are regularly exposed to passive smoking have an increased risk.

          8. Psychological stress

          Severe emotional or psychological stress can cause hormonal changes in the body that may increase the risk of miscarriage. Ongoing stress and exposure to stressful situations at work or in your personal life can have a particularly negative effect on your immune system, which can adversely affect your pregnancy.

          Prevention measures to minimize risk

          Some of the risk factors mentioned above can be influenced by a healthy lifestyle and medical care:

          • Regular check-ups: Early and regular care from a health professional can help detect and treat health problems early on. This includes regular checks of the pregnancy hormone.
          • Healthy eating: A balanced diet with plenty of folic acid, iron and other important nutrients is important for a healthy pregnancy.
          • No smoking or alcohol: It is crucial to completely avoid nicotine, alcohol and illegal substances.
          • Stress management: Techniques such as meditation, gentle physical activity and talking to loved ones can help to reduce stress.
          • Treatment of chronic illnesses: Women* with chronic illnesses should ensure that their illnesses are under control before and during pregnancy.
          • Bed rest: In some cases, especially with threatened miscarriage or cervical incompetence, bed rest may be medically recommended.
          • Hormone support: With diagnosed corpus luteum deficiency, hormone therapy can reduce the risk of miscarriage in early pregnancy.

            Symptoms of miscarriage

            It is important to recognize the symptoms of miscarriage so that you can react quickly in an emergency. The most common signs include:

            • Bleeding: heavy or persistent bleeding can be a sign of miscarriage. The blood from a miscarriage can be light to dark red and contain tissue fragments.
            • Abdominal pain: severe cramps or persistent pain in the abdomen can indicate a miscarriage.
            • Vaginal discharge: unusual discharge, especially if it contains tissue, may be a sign of miscarriage.

              It is important to note that miscarriage can also occur without bleeding (silent miscarriage or missed abortion). In this case, the pregnancy loss is often not detected until a routine examination.

              Medical procedures after miscarriage

              A range of medical procedures may be required after a miscarriage. These include:

              • Curettage or scraping: This procedure removes any remaining tissue from the uterus to prevent infection.
              • Drug treatment: In some cases, medication may be administered to help expel the pregnancy tissue.
              • Follow-up care: Regular follow-up visits are important to ensure that no complications arise.

                Coping emotionally and getting support

                Miscarriage can be a traumatic experience, often involving grief and feelings of loss. It is important to take time to grieve and seek professional psychological support if needed. Sharing your experience with others who have been through the same can also be helpful.

                Conclusion

                A variety of factors influence the risks during pregnancy, and miscarriages cannot always be prevented, even under the best of circumstances. However, knowing your individual risk factors can help you take a more informed and health-conscious approach to your pregnancy. The likelihood of miscarrying varies depending on individual factors, but preventive measures can often reduce the risk.

                Working closely with your medical team and implementing preventive measures increases your chances of a healthy and complication-free pregnancy. If you experience any signs of a possible miscarriage or have any concerns, you should always seek medical help immediately. With the right support and care, many women can experience a successful pregnancy despite previous miscarriages.


                References & Literature

                1. Deutsche Gesellschaft für Ernährung: Einheitliche Handlungsempfehlungen für die Schwangerschaft aktualisiert und erweitert. DGEinfo (12/2018) 183-189
                2. Leitlinie „gestörte Frühgravidität im ersten Trimenon“ AWMF-Register-Nr.:
                3. 015/076
                4. Qu F, Wu Y, Zhu YH, Barry J, Ding T, Baio G, Muscat R, Todd BK, Wang FF, Hardiman PJ. The association between psychological stress and miscarriage: A systematic review and meta-analysis. Sci Rep. 2017 May 11;7(1):1731. doi: 10.1038/s41598-017-01792-3. PMID: 28496110; PMCID: PMC5431920.