Sometimes there is no explanation for the loss of a pregnancy. Nearly all miscarriages are unexpected and are not preventable. A pregnancy may end in miscarriage for many reasons, including a weakness in the womb or cervix, a chromosomal abnormality, viral infections, diabetes, or placental malformation.
It is very rare for miscarriage to occur because of something you have or have not done, although many parents still feel this to be the case. For the majority of people, the cause of the miscarriage will never be known, even after extensive testing. Many parents have expressed feelings of frustration and helplessness when a cause for their miscarriage cannot be found.
Miscarriage and Pregnancy Loss
A miscarriage, or pregnancy loss, can happen for many different reasons. These may include a weakness in the womb or cervix, chromosomal abnormalities, infections, underlying health conditions such as diabetes, or problems with the placenta.
In many cases, there is no clear explanation. Nearly all miscarriages are unexpected and cannot be prevented.
Understanding the Causes
It is very rare for a miscarriage to occur because of something you did or did not do, although many parents may feel this way. For most women, the cause of miscarriage is never identified, even after extensive testing, which can lead to feelings of frustration and helplessness. Know that we are here for you and if you need support please reach our to our team via our 24/7 Grief and Loss Support Line on 1300 308 307 or visit the support section on our website.
Common Medical Causes
There are many possible reasons for early pregnancy loss, including:
Chromosomal abnormalities
Most occur by chance and are outside of anyone’s control.
Abnormalities with the embryo or foetus
Development may stop naturally if the embryo is not forming as expected.
Problems with implantation
The embryo may not properly attach to the uterine wall.
Placental development issues
The placenta may not form or function correctly.
Anembryonic pregnancy (previously called blighted ovum)
A fertilised egg implants, but does not develop into a baby. A pregnancy sac forms, and tests are positive, but miscarriage typically occurs between 7–12 weeks.
Health Conditions and Physical Factors
Chronic or poorly controlled illness
Conditions such as hypothyroidism or diabetes may increase risk if not well managed.
Cervical incompetence
The cervix opens too early, usually after 14 weeks, without pain.
Uterine abnormalities
Some women are born with a differently shaped uterus, which can increase risk.
Abdominal surgery
Rarely, surgery before 20 weeks may increase uterine irritability.
Severe trauma
A major injury to the abdomen may affect the uterus or placenta.
Infection and Immune Factors
Infections or viruses, such as listeria, toxoplasmosis, or cytomegalovirus.
Immunological factors
In some cases, the immune system may not support the pregnancy as expected.
Other Pregnancy Complications that may lead to miscarriage
Hydatidiform mole (molar pregnancy)
A rare condition where the placenta develops abnormally and no baby forms. In very rare cases, this can lead to cancer.
Ectopic pregnancy
When a pregnancy develops outside the uterus, most often in a fallopian tube. This can cause bleeding and severe abdominal pain and requires urgent medical treatment. While it may affect one fallopian tube, many women can still go on to have a healthy pregnancy if there are no other complications.
When to Seek Medical Advice
If you experience symptoms such as:
- Vaginal bleeding
- Severe abdominal pain
- Dizziness or fainting
Seek medical attention immediately, as some conditions (like ectopic pregnancy) can be life-threatening.
Getting More Information
If you have experienced a miscarriage or pregnancy loss, you may wish to speak with your doctor to better understand what may have happened.
Getting support
Red Nose supports anyone affected by the loss of a pregnancy, stillbirth, the death of a baby or child. Reach out to us 24/7 on our grief and loss support line 1300 308 307 or visit the support section of our website.
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