Miscarriage: Understanding Risk Factors and When to Seek Help

Miscarriage is more common than many people realise, yet it remains a deeply personal and often isolating experience. If you're pregnant or trying to conceive and have suffered a miscarriage or repeated (recurrent) miscarriages in the past, it's natural to wonder: What are my risks of miscarriage? This blog explains what factors may increase the risk of miscarriage, how miscarriage risk varies across different stages of pregnancy, and when it might be helpful to seek support or medical advice.

Understanding Miscarriage

A miscarriage refers to the loss of a pregnancy before 24 weeks, with most occurring in the first trimester (the first 12 weeks). Many early losses happen before a woman even realises she might be pregnant. It's important to know that miscarriage is rarely caused by something you did or didn’t do. Everyday activities like moderate exercises, work, or having sex are not linked to pregnancy loss.

How Common Is Miscarriage?

Miscarriage affects around 1 in 5 confirmed pregnancies*. However, some estimates suggest the real number could be higher when accounting for very early losses. While this can sound alarming, it's also important to understand that the likelihood of miscarriage typically decreases as pregnancy progresses.

When Is Miscarriage Most Likely to Happen?

• Weeks 4 to 6: This is when most pregnancy losses occur, often due to chromosomal issues in the embryo.
• Weeks 6 to 12: Risk begins to decrease, especially once a heartbeat is detected on an ultrasound scan.
• After 12 weeks: The chance of miscarriage drops significantly, particularly in the absence of risk factors.

What Factors Increase the Risk of Miscarriage?

Several factors can influence your risk: though many individuals with risk factors still go on to have healthy pregnancies and a majority of couple with no obvious risk factors sadly experience miscarriage.

1. Age

• Risk increases with advancing maternal age - women over 35 have a higher chance of miscarriage, which rises further after age 40*.
• Men over 40 years have an increased miscarriage risk, although less marked when compared with the effect of increased maternal age

2. Previous Miscarriages

• Having had one miscarriage doesn't mean you'll experience another. However, the risk of miscarriage increases with increase in the number of previous miscarriages.
• However, multiple losses may suggest an underlying cause and warrant further investigation.

3. Health Conditions

• Uncontrolled diabetes, thyroid disorders, prolactin imbalances, polycystic ovary syndrome, or autoimmune conditions can affect pregnancy.
• Being underweight or having a high BMI can increase the risk of miscarriage.
• Antiphospholipid syndrome (APS)
• Womb cavity abnormalities - congenital (uterine septum or bicornuate uterus) or acquired (intra-uterine adhesions, submucous/cavity distorting fibroids)
• Cervical insufficiency increases the risk of second trimester miscarriage
• Sperm DNA fragmentation significantly increases the risk of recurrent miscarriage
• Although luteal phase defect is a clinical entity, the diagnosis still remains challenging. The evidence is Insufficient/inconclusive for its association with miscarriage/recurrent miscarriage.

4. Lifestyle Factors

• Smoking, excessive alcohol intake (more than five alcoholic drinks per week), increased caffeine intake, and recreational drug use have been linked to higher miscarriage risk.
• High levels of unmanaged stress may also have an impact, though evidence is still emerging.

5. Fertility Treatments

• Fertility treatment assists in conceiving and doesn’t always mitigate the risk of miscarriage. The risk remains consistent with age and any underlying risk factors.

6. Chromosomal or Genetic Abnormalities

• Chromosome anomalies of the pregnancy are the most common cause of early miscarriage which often occur by chance*.
• Parental chromosome rearrangements increase the risk of recurrent miscarriage. If you suffer recurrent miscarriages, you may be offered genetic testing of the pregnancy tissue to see whether a recurring cause is identified. If this is not possible, you may be offered genetic testing for yourself.

Common Questions About Miscarriage Risk

What are the chances of miscarriage?

Evidence suggests the miscarriage rates to be 11.3%, 17.0%, 28.0%, 39.6%, 47.2% and 63.9% for women with no previous, one, two or three, four, five and six previous miscarriages respectively.

Despite recurrent miscarriages, most women go on to have a healthy live birth rather than a repeat miscarriage. Compared to a woman who has never miscarried, the risk of repeat miscarriage is slightly higher in those who have experienced recurrent losses.

Does age always mean higher risk?

Increased parental (both maternal and paternal) Age is associated with higher risk of miscarriage, but many women over 35 have healthy pregnancies, especially with good preconception care.

Does miscarriage risk change with IVF?

Risk of miscarriage appears to be same irrespective of mode of conception.

Does the risk of miscarriage reduces after seeing the fetal Heartbeat on scan?

Yes. Once a fetal heartbeat is detected (typically around 6 to 8 weeks), the chance of miscarriage reduces. For many, this milestone offers a sense of reassurance. However, it is not failproof, and sadly, miscarriage can still occur beyond this stage.

When Should I Speak to my GP or see a Specialist?

If you've experienced bleeding, cramping, or are concerned about your pregnancy for any reason, it's always appropriate to reach out to your GP or miscarriage specialist. Early reassurance scans and support has been shown to have beneficial effect in pregnancy outcomes.

If you've had repeated miscarriages, a specialist consultation can help prompt diagnosis of any underlying causes, and for appropriate management and support prior to and in future pregnancies.

Taking Care of Your Emotional Health

Miscarriage can be emotionally difficult, even when it happens very early. You're not alone, and it’s okay to seek support. Talking to a specialist counsellor, support group, or a trusted GP can help you process your experience and feel more empowered about your next steps.

Final Thoughts

While miscarriage is sadly a common part of the fertility journey, every individual’s situation is unique. If you're worried as you have had previous miscarriage, or that you may have risk factors that increase miscarriage risk, our Reproductive medicine Experts/Miscarriage Specialists at JIVA Fertility are here to support you with compassionate care. We offer investigations, early pregnancy monitoring, and personalised treatment plan to help you feel informed and cared for at every stage. Please visit JIVA Fertility for further information about recurrent miscarriage and our assessment packages.

Concerned about your risk of miscarriage?
Book a consultation with one of our Reproductive medicine specialists to get tailored support and answers you can trust.

References

1. National Institute for Health and Care Excellence (NICE) – Clinical Knowledge Summaries. https://cks.nice.org.uk/topics/miscarriage
2. NHS Inform – Causes of Miscarriage. https://www.nhsinform.scot
3. Royal College of Obstetricians and Gynaecologists (RCOG). https://www.rcog.org.uk
4. American College of Obstetricians and Gynecologists (ACOG) – Early Pregnancy Loss. https://www.acog.org

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Disclaimer: This article is intended for educational purposes and does not replace individual medical advice. Please consult a healthcare provider for assessment and treatment decisions.

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