October is Pregnancy and Infant Loss Awareness Month, a time to remember the babies who were lost during pregnancy, at birth, or shortly after.
What is a miscarriage?
A miscarriage is the spontaneous loss of a pregnancy before 20 weeks of gestation (before the baby would be able to survive outside the womb). It happens when the embryo or fetus stops developing, and the pregnancy ends naturally. Unfortunately, 1 in 4 pregnancies end in a miscarriage.1
Evidence suggests that most miscarriages happen in the first trimester (the first 12 weeks of pregnancy).2
Common causes of miscarriage
Miscarriages are often caused by factors beyond the pregnant person’s control; in most cases it happens because the pregnancy was not developing normally. There are several different reasons why a miscarriage could occur:
Maternal health related
Certain medical conditions such as diabetes, thyroid disease, blood clotting disorders and autoimmune conditions (like lupus) can increase the risk of miscarriage.3 Some infections during pregnancy can also cause complications leading to miscarriage. Lastly, structural abnormalities such as uterine fibroids or scarring in the uterus can affect implantation of the embryo leading to early loss of the pregnancy.
Lifestyle and environmental factors
While most miscarriages are not caused by lifestyle, certain exposures may contribute to an increased risk. These include smoking, alcohol, drug use, high levels of radiation, toxic chemicals or severe malnutrition.
Genetic related
The most common cause of early pregnancy loss is genetic in nature. Chromosomal abnormalities in the fetus can result in a spontaneous loss due to abnormal development. Chromosomes are structures in our cells that carry genetic material, and each fetus normally has 46 chromosomes, 23 from the mother and 23 from the father. Having the correct number of chromosomes is known as a ‘euploid ’ fetus.
Sometimes, during the formation of the egg or sperm, a mistake occurs, leading to an extra chromosome, a missing chromosome, or structural changes in one of the chromosomes. This is known as ‘aneuploidy’. Sometimes there could be a mix of normal and abnormal cells which is then called a Mosaic.
These errors usually happen by chance and mostly cannot be attributed to anything the parents have done, which means they generally cannot be prevented. When such a DNA error occurs, it can interfere with the proper development of the fetus leading to a miscarriage of that pregnancy.
Products of Conception Screening (POCScreen) is a genetic test that can help identify these chromosomal abnormalities providing answers as to why the loss has occurred. During a POCScreen test, tissue from a miscarriage is collected by your doctor and sent to the Next Biosciences’ laboratory. The tissue is analysed for the presence of chromosomal abnormalities, providing answers and an action plan for your doctor to assist in future pregnancies.
Understanding this can also help parents realise that most early miscarriages are due to natural biological processes, rather than lifestyle choices or actions taken during pregnancy and can assist a couple in finding closure and acceptance after a loss.
South African statistics
Chromosomal abnormalities are responsible for approximately 50% of miscarriages, making them the single biggest contributor to early pregnancy loss.2 The figure below shows South African statistics obtained through Next Biosciences POCScreen testing on miscarriage tissue. 45.8% of miscarriages were due to genetic chromosomal abnomalities (mosaic and aneuploidy results) that could not have been prevented. Finding an explanation for why the loss occurred can help couples reach acceptance and also support healthcare providers in offering more personalised care during future pregnancies.
In cases where no chromosomal abnormality is identified (54% euploid), your clinician may focus investigations on other potential causes of miscarriage such as maternal factors, to help determine an accurate risk of recurrence. Next Biosciences also offers genetic counselling to help understand POCScreen results better.
Depending on the severity and type of chromosomal abnormality, the embryo may not develop fully or properly, often resulting in a non-viable pregnancy and miscarriage, typically in the first trimester. In the below graph chromosomal abnormalities (blue bar) are responsible for more losses at an earlier gestational age (1-12 weeks) rather than later in pregnancy.
Miscarriage and infant loss are not rare, and they should not be hidden. By raising awareness, we can foster empathy, provide better support, and help grieving families heal.
If you or someone you love has experienced pregnancy or infant loss, know that your grief is valid, your story matters, and you are not alone.
Contact genetics@nextbio.co.za for more information or access our pregnancy loss support document here
References
- American Society for Reproductive Medicine (ASRM) (2012) ‘Evaluation and treatment of recurrent pregnancy loss: a committee opinion’, Fertility and Sterility, 98(5), pp. 1103–1111.
- The American College of Obstetricians and Gynecologists (2015) ‘Early pregnancy loss’, Practice Bulletin No. 150. Obstetrics and Gynecology, 125(5), pp. 1258–1267
- Abdelghani, A.M.A., Mahdi, E.R., Abohashim, M.F. and Alqaed, M.B.O. (2023) ‘Miscarriage Risk Factors and Causes: Review Article’, The Egyptian Journal of Hospital Medicine, 91(1), pp. 4984–4987. doi: 10.21608/ejhm.2023.301778
- Wapner, R.J., Martin, C.L., Levy, B. et al. (2012) ‘Chromosomal microarray versus karyotyping for prenatal diagnosis’, New England Journal of Medicine, 367(23), pp. 2175–2184.
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