Abnormal genes or chromosomes

Most miscarriages occur because the fetus isn't developing normally. Problems with the baby's genes or chromosomes are typically the result of errors that occur by chance as the embryo divides and grows — not problems inherited from the parents.

Examples of abnormalities include:

  • Blighted ovum. Blighted ovum occurs when no embryo forms.
  • Intrauterine fetal demise. In this situation the embryo is present but has stopped developing and died before any symptoms of pregnancy loss have occurred.
  • Molar pregnancy. A molar pregnancy is a noncancerous (benign) tumor that develops in the uterus. A molar pregnancy occurs when there is an extra set of paternal chromosomes in a fertilized egg. This error at the time of conception transforms what would normally become the placenta into a growing mass of cysts. This is a rare cause of pregnancy loss.

Maternal health conditions

In a few cases, a mother's health condition might lead to miscarriage. Examples include:

  • Uncontrolled diabetes
  • Infections
  • Hormonal problems
  • Uterus or cervix problems
  • Thyroid disease

What does NOT cause miscarriage

Routine activities such as these don't provoke a miscarriage:

  • Exercise
  • Having sex
  • Working, provided you're not exposed to harmful chemicals or radiation.
Jul. 09, 2013