Miscarriage, also known as spontaneous abortion and pregnancy loss, is the natural death of an embryo before 20 weeks of pregnancy (this definition may change from country to country). Although not well known, a miscarriage is something that is happening quite often. It is estimated that out of all women that realised they were pregnant, 1 in 6 will have a miscarriage. Even more miscarriages happen before the mother realises she is pregnant. Losing three or more pregnancies in a row (recurrent miscarriages) is uncommon and affects 1 in 100 women.
What causes a miscarriage?
There are many reasons that contribute to a miscarriage, although we cannot identify the exact cause.
If the miscarriage happened in the first trimester of pregnancy, it is usually due to problems found on the baby. Most of the miscarriages (three out of four) happen at this stage.
If the miscarriage happens after that stage, then the causal factor might have been some maternal medical problem, an infection of the baby that caused waters to break or some incompetence of the cervix that opened prematurely.
What are the commonest causes of a miscarriage in the first trimester?
- Chromosomal abnormalities.
At some point of conception, an accident happened and the baby got abnormal genetic material with which life was incompatible. Approximately two out of three miscarriages happen because of problems with the baby’s genes. This is extremely rare to happen again and does not imply that there is some problem with the parents’ chromosomes.
- Problems in the placenta.
Placenta is the organ that connects the blood circulation of the mother with that of the growing baby. If there is a problem in the placenta this can lead to a miscarriage.
What are the factors that increase the risk of a miscarriage in the first trimester?
Most of the times, miscarriage happens because of an accident. There are, however, some known factors that increase the probability :
- mother’s age
- caffeine abuse
- alcohol consumption
What are the factors that increase the risk of a miscarriage in the second trimester?
The most important factors are:
- chronic medical problems (diabetes, hypertension, lupus, kidney disease, thyroid disease, celiac disease)
- infections (rubella, cytomegalovirus, bacterial vaginosis, HIV, chlamydia, gonorrhea, syphylis, malaria)
- food poisoning (listeria, toxoplasmosis, salmonella)
- drugs (misoprostole, retinoids, methotrexate, NSAID)
- womb structure (submucous fibromas, congenital abnormalities in the womb structure)
- cervical incompetence (short cervix, collagen disease that change the cervical composure)
- polycystic ovaries syndrome (not concrete evidence)
What are the symptoms of a miscarriage?
- Vaginal bleeding.
This is the most common symptom of a miscarriage. Bleeding can vary in intensity, from spotting to heavy bleeding and from dark brown color to bright red.
- Cramps or continuing pain low in the tummy.
- Watery vaginal discharge.
- Tissue discharge from the vagina.
- Receding of the pregnancy symptoms, such as sickness or breast tenderness.
In this case, please get in contact with us immediately so we can identify the exact cause of the symptoms and to exclude more serious conditions like an ectopic or a molar pregnancy.
How is a miscariage diagnosed?
We can diagnose a miscarriage by blood tests and ultrasound scans.
The first test done is an ultrasound scan to check the baby’s growth and heartbeat. Usually, this is done by a vaginal scan so the picture is as clear as possible. The vaginal scan is absolutely safe for both the mother and the baby and the discomfort is minimal. If the vaginal scan is declined, we can always try to perform the scan from the tummy even though the picture quality is going to be worse and maybe establishing the diagnosis is going to be harder.
Additionally, measuring two pregnancy hormones in your blood, beta chorionc gonadotropin (β- hCG) and progesterone, can be helpful. In a few cases, we might need to repeat the tests if:
- results are marginal
- the scan is inconclusive
- the pregnancy is at very early stage
Miscarriages are called recurrent when there are three or more consecutively repeated miscarriages of clinically identified pregnancies. Others suggest that the definition should be somewhat different and further testing and treatment is warranted for women that had two consecutive miscarriages, especially if there are certain factors like age (women over 35 years old) and a history of sub- fertility.
If you had recurrent miscarriages, you might need to do some further, specialised testing. Below are presented some suggestive tests.
You and your partner might nned to be tested for any abnormalities in your chromosomes that can be the cause of the problem. This is a relatively rare cause of miscarriages, but if a problem is identified, you will have to discuss findings with a clinical geneticist.
- Ultrasound scans.
A gynecological scan will be needed to check your uterus for any structural defects, polyps or fibromas. Additionally, your cervix will be checked. You might need to have a 3D gynecological scan. Sometimes, hydrosonography can be beneficial to assess the endometrial cavity.
- Hysterosalpingography, Hysteroscopy, Laparoscopy
Routinely using hysterosalpingography to detect congenital anomalies of the womb in women with recurrent miscarriages does not seem to have any advantage over ultrasound. Hysteroscopy and laparoscopy are only needed in case there is some doubt about the diagnosis or a surgical treatment is needed.
- Blood tests
Suggestive tests include, a complete blood count, glucose tolerance test, HbA1C, thyroid function, antiphosholipid and lupus Ab, homocysteine, MTHFR, thrombophilia panel, immunoogical tests.