Miscarriage causes, symptoms, diagnosis & treatment

Miscarriage means a pregnancy which ends before the fetus has reached a viable gestation age (usually 20 weeks) due to known or unknown reasons. Miscarriages are common and almost one in four of all pregnant women will experience it.

Miscarriage is not a pleasing experience and can affect the couples who are trying to conceive a child, emotionally as well as psychologically. The good news is though that even in the case of recurrent miscarriages (history of 3 or more miscarriages) the chances of successfully giving birth is still high >50%. 

Maintaining a healthy lifestyle with proper nutrition, a proper BMI (Body Mass Index), awareness of your medical condition, properly planning your pregnancy go a long way in preventing miscarriage.

Here we are trying to summarize few causes of miscarriage and information regarding diagnosis and treatment of miscarriage.

Miscarriage: What, How & When?

Miscarriage means loss of pregnancy any time before 24 weeks of gestation calculated from the last day of the previous menstrual day. More than 50% of the miscarriage cases remain unnoticed as the loss of pregnancy will happen before 12 weeks of gestation and in most of the cases, the woman isn’t aware if she was pregnant.

For the rest of the cases, 50% of cases will have some underlying causes and other 50% cases, the cause will not be clear or might require intensive clinical testing which might be expensive.

Recurrent miscarriage or habitual abortion is termed as three or more consecutive miscarriage. It is known to affect 1% - 2% of the women.

The women with a history of live births will have a low incidence of miscarriage (~ 5%) on the other hand women with a history of miscarriage will have a higher risk of subsequent miscarriages and this increases with the number of miscarriage where post first miscarriage the risk is approx. 20% and it increases with two (28%) and three or more (around 43%). 

Reasons or Causes of Miscarriage

As discussed more than 50% of miscarriage cases remain unidentified post examination, the other cases can be categories based on the underline causes which can be classified as:

• Nutrition, environmental risks
• Chromosomal Defects
• Anatomical condition
• Hormonal Defects
• Thrombophilic defects
• Autoimmune disorders
• Infections
• Other medical conditions

The maternal age also plays an important role as the women in their mid-30s are more susceptible to miscarriage then a women before 30 years of age and similar trend reciprocate in 40+ age groups.   

1. Nutritional & Environmental risks

• Coffee consumption: More than 4 cups per day in the early stages of pregnancy is associated with miscarriage.
• Smoking & Alcohol: Mothers smoking with cocaine in the early stages of pregnancy increases the chances of miscarriage. Alcohol consumption with 3 or more units per week, especially in the first 10 weeks of pregnancy, is associated with increased risk of miscarriage.
• Hyperhomocysteinaemia: Homocysteine is a non-essential amino acid whose level generally fall during pregnancy. The high level of homocysteine is associated with various pregnancy-related defects like neural tube defect, fetal growth retardation, placental abruption etc. The most common cause for this situation is folate deficiency.
• Stress: Stress does not contribute directly to miscarriage but is believed to be linked through immunological imbalances.

2. Chromosomal Defects

One of the most common causes of miscarriage is when the embryo receives an abnormal number of chromosomes during fertilization. This can be caused either from mother side or father side.

3. Anatomical Condition

The anatomical abnormalities account for 10-15% of total recurrent miscarriage cases and they affect by impacting the blood circulation to the endometrium, for abnormal implantation of the fertilized egg.

• Congenital uterine abnormalities: These are innate uterus structure abnormalities which causes miscarriage as the implantation is effected due to shape of the uterus. The most common is septate uterus where the uterus is divided into 2 parts with wall of tissues. The others include Bicornate uterus (there is deep indentation at the top of the uterus) or Didelphhys which is having two uterus with two cervices.
• Asherman’s syndrome (Endometrial fibrosis): The adhesions or scarring is formed in the uterus which hinders with the implantation and results in repeated miscarriage.
• Uterine fibroid: These are non-cancerous growths within the muscles of the uterus (intramural fibroid) or within the uterine cavity (submucosal fibroid) which can affect the plantation, delivery or painless miscarriage.

4. Hormonal Defects

• Polycystic ovaries (PCO): The morphological changes due to PCO doesn’t really increase the risk of miscarriage, it is the hormonal changes, hyperinsulinemia and hyperandrogenaemia, associated with PCO which are believed to increase the risk of miscarriage.
• Hyperandrogenaemia: High levels of androgens are linked to retardation of the endometrial in the luteal phase of the cycle (post-ovulation phase) and can impact the plantation of egg resulting in miscarriage.
• Hyperprolactinaemia: A study suggests that women with recurrent miscarriages have an elevated prolactin level during follicular maturity stage.

5. Thrombophilic Defects

An abnormality which can increase the tendency of blood clotting

• Thrombin anti-thrombin (TAT): A global marker for thrombin generation which promotes clotting of blood, was found very high in women with recurrent miscarriage.
• Thromboxane: prostacyclin ratio: The women with RM were found to have excess production of thromboxane in week 4-7 and low prostacyclin in week 8-11. This increase in the overall value of thromboxane in thromboxane: prostacyclin ratio leads to vasospasm and platelet aggregation which causes an increase in blood clots and finally blocking blood supply in the placenta.
• Factor V Leiden: It is the most common deficiency found inheritable thrombophilia. This factor has been reported in women with recurrent miscarriage.

6. Immunological Factors

Immunological mechanisms are involved in successful implantation. The fertilized egg possess paternal antigens so if it is not accepted by the mother responses the implantation will be affected leading to miscarriage.

• Diabetes: A close glycemic control in pre-conceptual period is recommended to avoid miscarriages.
• Thyroid antibodies: In a study, almost 31% of women with RM (Recurrent Miscarriage) gave a positive result for one or both of the thyroid antibody (peroxidase & thyroglobulin). The women who miscarried in subsequent pregnancy were found to have more quantity of these antibodies than the women who had a live birth.
• Antiphospholipid Syndrome: A condition where antibodies will increase the tendency of blood to clot and is responsible mainly for second-trimester miscarriages. The first trimester miscarriages are more linked to defective implantation.
• Increased NK cells (Natural Killer Cells): The portion of activated NK cells was found to be more in peripheral blood NK cells of women with recurrent miscarriage cases.

7. Infections

Some of the maternal infections can lead to pregnancy loss once like listeriosis, toxoplasmosis, and certain viral infections (rubella, herpes simplex, measles, cytomegalovirus, coxsackie virus.

Recurrent Miscarriage is known to be associated with Bacterial vaginosis (BV), a condition of alteration in vaginal flora. Another condition associated with RM is chronic endometritis caused due to bacteria.

8. Other Medical Conditions

Some other diseases apart from Diabetes mellitus, thyroid can also increase chances of recurrent miscarriage like kidney diseases, chronic hypertension, prolonged hypoparathyroidism (a condition causing a decreased level of calcium and increased level of phosphorus in blood)

Diagnosis / Assessment of recurrent miscarriage

To identify the actual cause behind the miscarriage or recurrent miscarriage the physician might ask about medical history, genetic history or previous pregnancies.

The physician will perform a physical examination, blood testing for thyroid function, diabetes, thrombophilia and ultrasonography for uterus or uterine cavity examination. In some rare cases after 2 or 3 pregnancy losses, a karyogram (Parental chromosome testing) might be recommended.

Signs/ Symptoms of Miscarriage

In some cases of miscarriage there will not be any signs or symptoms but if you do notice one or all of the below-mentioned symptoms you should immediately contact your physician to evaluate if you having any miscarriage:

• Mild to severe pain or cramps in the abdomen or back pain 
• Mucus discharge from the vagina which is white-pink in colour.
• Bleeding with clots or tissues
• Sudden Weight loss
• The decrease in the symptoms of pregnancy ( depends on what symptoms you were having)
• Spotting which is lasting more than 3-4 days.
• Painful Contractions happening every 5-20 mins.

Treatment of recurrent miscarriage

The efficiency of treatment is mainly based on the identification of the root cause.

• The patients with genetic or chromosomal problems will need genetic counselling for future pregnancies through adoption, donor gametes etc.
• The patients will uterine abnormalities, PCOS would require surgery in most of the structural defect cases.
• In cases of Antiphospholipid syndrome, thrombophilia women would need drug therapy with heparin or aspirin or combination, folic acid supplements, etc.
• Cervical incompetence (weakness) would need cervical cerclage (stitching)
• Immunological therapy might be needed in the cases where there are issues with maternal immunological adaptation to the fertilized egg.
• Smoking, Coffee, alcohol consumption should be restricted to as low as possible, the recommended is still to avoid it completely. Homocysteine levels can be maintained with folic acid and other vitamin supplements.