7 Possible Causes of Pregnancy Loss

Pregnancy loss or miscarriage is the natural loss of pregnancy prior to 20 weeks of gestation, commonly occurring by 13 weeks of gestation. It is estimated that 10 – 25 % of all pregnancies result in pregnancy loss. The symptoms include back pain, pinkish vaginal discharge, bleeding while pregnant, contractions, passing tissue-like clots and the sudden loss of pregnancy symptoms.

It is reported that 50 – 75 % of all miscarriages are chemical pregnancies, wherein the fertilized egg is lost shortly following implantation. Women may not be aware of a chemical pregnancy, because her period starts close to the expected time. Another type of miscarriage is a blighted ovum, or anembryonic pregnancy, wherein the pregnancy implants into the uterus, but fetal tissue development ceases.

Another way a pregnancy is lost is with an Ectopic pregnancy.  An ectopic pregnancy is when the pregnancy implants in a place other than the uterine cavity( i.e. in the tubes , on the ovaries, in the abdomen), and therefore normal development of the pregnancy cannot occur. Molar pregnancy is yet another example of a type of pregnancy that results in pregnancy loss. It happens due to genetic error during fertilization that leads to abnormal tissue growth in the uterus.

Many times the exact cause of a the pregnancy loss cannot be deciphered. Here are the most common causes of a miscarriage:

1. Chromosomal Abnormality: This is common for first trimester miscarriages, and can result from chromosomal abnormalities in the egg, or sperm, or from mistakes during the formation of the baby. As many as 65% of all early miscarriages are due to chromosomal abnormalities.


2. Maternal health: Chronic maternal health problems, such as diabetes, high blood pressure, lupus, thyroid disorders, celiac disease, may increase the risk of having a miscarriage. Infections, such as rubella, chlamydia, gonorrhea, syphilis, cytomegalovirus, bacterial vaginosis, are also associated with elevated miscarriage possibility.

3. Uterine structural abnormalities: If a woman’s uterus has abnormalities, such as the presence of fibroids, polyps, abnormal shape, weak cervix (from injury of surgery), the chances of having a miscarriage increases.


4. Maternal age: It has been reported that the risk of having a miscarriage increases with maternal age. Therefore, for women below 30 years of age, only 1 in 10 pregnancies result in miscarriage, whereas for women above 45, greater than half of all pregnancies can be miscarried.


5. Lifestyle: A woman’s lifestyle choices can impact her health as well as that of the fetus. Smoking and drinking more than the increase the rate of pregnancy loss.  Certain medications should be avoided during pregnancy, because of the risk of miscarriage. These include misoprostol, retinoids, methotrexate and non-steroidal anti-inflammatory agents. Women should consult with their physician before starting any new medications during conception and pregnancy.


6. Implantation problems leading to improper attachment of the egg with the uterine lining.


7. Abnormal type of pregnancy:  all ectopic gestations, complete molar pregnancies and chemical pregnancies result in loss of the pregnancy.


Healthy women in their reproductive years have a 10 – 20 % chance of having a miscarriage. Women who had a previous miscarriage has a 25% increased chance of having another one. Recurrent miscarriage, defined as 2 or more consecutive miscarriages can occur in 4% of couples.


The earlier on during pregnancy that a miscarriage occurs, it is more likely that the body will remove all fetal tissues on its own. However, in cases where the body is unable to expel the miscarriage tissue, the use of medication (misoprostol) or a dilation and curettage (D&C) can be performed. The goal of treatment for a miscarriage is to control bleeding and prevent infections in the woman.  Chemical pregnancies resolve on their own.  Molar pregnancies require an D and C and lengthy follow up.  Ectopic pregnancies can be treated by observation, medication (methotrexate) or surgery.


Chromosomal aberrations are the root cause of most miscarriages, and therefore it is not really possible to prevent most miscarriages. Couples may, however, lead a healthy lifestyle prior to conception to improve their chances of a healthy pregnancy. Once a woman becomes pregnant, she can follow medically recommended guidelines, such as avoidance of smoking, alcohol, contact sports, unsafe medications and radiation hazards, to keep her baby safe.

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