Once a woman undergoes a pregnancy loss she will feel emotionally and psychologically traumatized. Questions will naturally surface as to WHY the miscarriage happened: whether it could have been prevented, and what are the implications for the next pregnancy.



Miscarriage can be caused by many factors; below are the 8 common causes.



• Chromosome or genetic abnormalities in the pregnancy:


There are 46 chromosomes (23 pairs) in the cells of your baby. The chances of a miscarriage are higher if there is a chromosome abnormality i.e. there is one extra chromosome in every cell of your baby's body. This 47th chromosome is responsible for abnormalities such as Down's syndrome, Edward's syndrome or Patau's syndrome. Turner's syndrome occurs if there is one less sex chromosome (45 in total). Genetic abnormalities such as thalassaemia major also become a factor for causing a miscarriage.

Most miscarriages occur in the first 12 weeks of pregnancy, with the majority taking place between the 9th and 11th week.

Most chromosomal abnormalities discovered in a miscarriage are not inherited ones but occur because of a defect in the cell division that formed the particular egg or sperm. Because of this most miscarriages are isolated events not likely to repeat. There are instances however, where the defect is an inherited disorder – this is when the abnormality of chromosome is an abnormality of structure rather than abnormality of number. For miscarriages due chromosomal abnormalities at least 95% are due to abnormalities of chromosome of number.

• Structural deformity in the fetus:


Structural deformities include defects of the brain, heart, spine, intestinal tract and kidneys. Fetal organs develop largely in the first trimester and all the key organs are formed by the 14th week of pregnancy. Any major defect can develop in this time frame and lead to a risk of miscarriage. For example a fetal heart not developing properly can cause the heart activity to stop, even if it was beating previously. Sometimes an embryo fails to progress in its growth and an ultrasound examination will reveal a sac without a visible fetus – this is known commonly as missed abortion. Such pregnancies are not viable to begin with, and will eventually lead to bleeding and expulsion of the pregnancy sac.


• Inadequate pregnancy hormones causing an inadequate placental implantation:


In some pregnancies the placenta fails to implant properly into the uterine wall. This is sometimes caused by lower levels of progesterone, a pregnancy hormone produced by the ovary and later the placenta. Inadequate levels of hCG, another pregnancy hormone produced by the placenta have also been associated with a miscarriage. Bleeding from the placenta may occur and cause a miscarriage to result.


• Viral infections:


In early pregnancy if you contract an infection and have a high fever, you are at risk of a miscarriage. Most fevers are controllable with proper medication; your doctor's advice is necessary as to which medication is safe and suitable. Infections such as parvovirus, coxsackie virus and cytomegalovirus can result in miscarriages.

Pregnancies that are conceived within 3 months of a live birth have a high chance of miscarrying.

• Maternal disease occasionally causes miscarriage:


Unregulated diabetes increases the risk for miscarriage – a poor adherence to diet and the incorrect use of insulin may result in a pregnancy loss. Hypothyroid or underactive thyroid has been associated with miscarriage just as excessive levels of thyroxin produced by an overactive thyroid. Celiac disease, another illness if left untreated, can result in a miscarriage.


• Auto-antibodies in the mother's blood:


These auto-antibodies can cross into the developing fetus and placenta and cause the woman to miscarry. Women with SLE or systemic lupus are at higher risk of miscarrying.


• Maternal diet:


Severe malnutrition can contribute to this loss. But food alone is not the cause - if a mother lacks in nourishment or eats poorly the embryo is not miscarried. Instead habits such as drinking and smoking increases the rate. One study showed that 5 cigarettes a day increased the possibility and drinking alcohol twice a week increases the chance of miscarrying. There are mixed reviews on caffeine intake so it is prudent to limit its consumption.


• Abnormalities of the uterus:


The presence of fibroids or an abnormally shaped uterus may lead to a miscarriage. Defects in the body of the uterus and in the cervix may cause a miscarriage. Sometimes such defects may result from prior surgical procedures such as severe postpartum bleeding in a previous pregnancy. Fibroid tumors may distort the shape of the uterine cavity and interfere with the growth of the embryo – this happens when the fibroid is on the inside of the uterus lining or muscle. Mostly, fibroids do not interfere with pregnancy.

Often the cause of miscarriage is never determined because most women who have miscarried do not have a repeat miscarriage.

Many more eggs are fertilized than pregnancies achieved. Some of these eggs undergo a few cell divisions in the fallopian tubes and cease to develop further. Some enter the next stage where the cells divide further but fail to implant in the uterus. Some implant close to a blood vessel in the lining of the uterus and cause a hemorrhage which expels them. Just imagine! All these take place before a woman misses her periods.

Common Myths

There are many myths and fallacies that have been pegged as the causes of a failed pregnancy, especially in Asian cultures. Many of these myths create unnecessary guilt and it is certainly a good idea to be informed on the facts. Pregnancy losses are not due to something you did or didn’t do – here are some of the common miscarriage-related myths:


• I miscarried because of something I ate.


Generally miscarriages are not caused by an inadequate diet. You should however make every attempt to eat sensibly – a diet balanced with protein, calcium, carbohydrates, fiber and folate-rich foods is a prerequisite. Do not compromise on hygiene. Prepare your meals at home in a clean environment away from pets. Make sure your food is well washed and well-cooked; avoid undercooked foods and herbs you are not familiar with. Avoid beverages, nicotine and alcohol during your pregnancy months.


• My miscarriage was due to the stress at work.


Work stress seldom impacts a pregnancy; maintaining a healthy lifestyle with regular meals, adequate rest and activity will help keep stress at bay.


• My uterus was too weak.


Unless you have undergone multiple D&Cs, this situation is unlikely. Repeated dilatations may weaken the cervix causing cervical incompetence. The cervix may open up during the second trimester and cause a miscarriage. The solution: a stitch has to be inserted to close up the cervix in the early stages of pregnancy.


• I should have refrained from sexual intercourse during pregnancy.


Sex is generally safe during pregnancy, unless you experience any bleeding during pregnancy, have an active vaginal infection or your membranes have ruptured. Check with your doctor who may run some tests and advise you accordingly.


• I should not have carried those heavy stuffs.


Physical exertion is normally not to be blamed in a normal pregnancy, as long as your body is comfortable with it and you have not experienced any bleeding recently. In cases where there is some recent bleeding, bed rest is prudent and a check with the doctor a must. A sedentary lifestyle is not advisable when you are pregnant; some exercise, which your body allows, is important.


• My body was too weak.

Unless you are anemic or have diabetes or an auto-immune disease, it is unlikely that your ‘weakness’ will affect your pregnancy. However you should work on having an ideal body mass index before you get pregnant.