Early miscarriage

Most miscarriages occur during the first 12 weeks of pregnancy. Miscarriages that happen in this period are called early miscarriages.

A miscarriage is called an ‘early’ miscarriage or a 'first trimester' miscarriage if it happens within the first 12 weeks of pregnancy. Most miscarriages occur during this period.

Causes of early miscarriage

Most early miscarriages are caused by genetic problems within the developing baby but a poorly formed placenta can also cause problems.

  • Chromosomal problems

Chromosomes are blocks of DNA which contain the instructions for developing every single part of your baby.  They are found inside every single cell of the body.  When something goes wrong at conception or during the development  of the baby’s chromosomes, it can cause genetic abnormalities.  If these problems are incompatible with life, or normal development, you may lose the baby.

It’s estimated that up to  nearly half of early miscarriages are associated with chromosomal problems in the baby.  But these problems don’t mean there is any problem with your own chromosomes or your partner’s chromosomes. Most couples who experience miscarriage as a result of chromosomal problems go on to have a healthy baby in the future.

  • Placental problems

The placenta is an organ which links your blood supply to the baby’s.  This life-giving link is essential to a developing baby, so if there is a problem with the development of the placenta, it can also lead to miscarriage.

Read more about miscarriage



  1. NICE (2012) Ectopic pregnancy and miscarriage: diagnosis and initial management in early pregnancy of ectopic pregnancy and miscarriage, clinical guideline CG154, National Institute for Health and Care Excellence
  2. Stillbirth (Definition) Act 1992, Definition of stillborn child, Section 1(1), London The Stationery Office, 1992
  3. RCOG (2008) Early miscarriage: information for you, Royal College of Obstetricians and Gynaecologists, , 2008
  4. RCOG (2008) Bleeding and Pain in early pregnancy: information for you, Royal College of Obstetricians and Gynaecologists, 2008
  5. RCOG (2012) Recurrent and late miscarriage: tests and treatment of couples, information for you, London Royal College of Obstetricians and Gynaecologists
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Last reviewed on August 1st, 2016. Next review date August 1st, 2019.

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