Miscarriage – recurrent miscarriage

Miscarriage is defined as spontaneous loss of pregnancy before fetus reaches viability, which include all pregnancy losses from the time of conception until 24 weeks of gestation.**After 24 weeks of gestation, the term ‘stillbirth’ is used. 

Miscarriage is a common pregnancy complication. About 1 in 5 pregnancy ends with miscarriage. Usually, miscarriage is a complication that occurs by chance. A woman with 1^st time 1^st trimester miscarriage will be expected to have a normal following pregnancy just like any other normal lady. However, if a woman develops recurrent miscarriage or 1 or more 2^nd trimester miscarriage, the cause of the miscarriage should be investigated.

The causes and risk factors of recurrent miscarriage include: 1) Increase maternal age 2) Increase number of previous miscarriage 3)Obesity  4)Anti-phospholipid syndrome 5)Genetic abnormalities 6)Endocrine disorder 7)Infection 8)Thrombophilia 9)Anatomical abnormalities.

Advancing maternal age is associated with a decline in both number and quality of the remaining oocytes (eggs). Advanced paternal age has also been identified as a risk factor for miscarriage. The risk of miscarriage increases when a woman is 35 years old and above, and when a man is 40 years old and above. Meanwhile, for  women with history of successive pregnancy losses, the risk of further miscarriage increases with each successive pregnancy loss.

Anti-phospholipid syndrome is the most common treatable cause of recurrent miscarriage.It is a syndrome characterized by association between the presence of anti-phospholipid antibodies and pregnancy complications or vascular thrombosis. The pregnancy complications said may include 1 or more of the following: 1)3 or more consecutive miscarriage before 10 weeks gestation. 2)1 or more morphologically normal fetal losses after 10 weeks gestation. 3)1 or more preterm birth before 34^th weeks gestation due to placental disease.

Miscarriages caused by genetic problem can be either due to abnormality in the parents’ chromosome (parental chromosomal abnormality), or due to abnormality in the embryo chromosome itself (embryo chromosomal abnormality).

There is a number of maternal endocrine disorders which have been associated with increased risk for miscarriage. These include diabetes mellitus, thyroid disorder and polycystic ovarian syndrome. Obesity is also known as a risk factor for miscarriage.

Anatomical abnormalities of the female organ also can lead to recurrent miscarriage. These include congenital uterine malformation such as arcuate uteri and septate uteri, and cervical weakness. Cervical weakness or incompetence usually leads to 2^nd trimester miscarriage.

Other causes include infection and thrombophilia. Infection such as bacterial vaginosis usually leads to 2^nd trimester pregnancy losses and preterm delivery.  Meanwhile, thrombophilia, whether inherited or acquired, is said to be the possible cause of recurrent miscarriage and late pregnancy complication - with presumed mechanism being - thrombosis of utero-placental circulation.