Last updated: December 2012
A miscarriage is the loss of a pregnancy that happens sometime during the first 23 weeks. Around three quarters of miscarriages happen in the first 12 weeks of pregnancy (the first trimester) .
The most common symptom of miscarriage is vaginal bleeding. Other symptoms include:
• cramping and pain in the lower abdomen
• a discharge of fluid or tissue from the vagina
• no longer experiencing the symptoms of pregnancy, such as no longer feeling sick, no longer having breast tenderness.
• It is extremely difficult to obtain accurate statistics on miscarriage for several reasons and especially since the majority of miscarriages occur before the mother realises she is pregnant.
• About one in seven recognised pregnancies end in miscarriage, while the incidence of spontaneous (unrecognised) miscarriage is estimated to be 50% of all pregnancies [2, 3].
• However, even if we restrict the figures to recognised pregnancies, the miscarriage rate is difficult to determine because many remain unreported. The following statistics are best estimates based on the most reliable sources available.
• One in four women who get pregnant will experience a miscarriage. This figure drops to one in five when only taking women who have had a positive pregnancy test into consideration .
Pregnancy history and risk of miscarriage 
First pregnancy: 5 percent
Last pregnancy a live birth: 5 percent
All previous pregnancies resulted in live birth: 4 percent
Last pregnancy miscarried: 19 percent
All previous pregnancies miscarriaged: 24 percent
Risk of miscarriage at various ages 
Under 30: 10 percent risk of miscarriage
35-40: 20 percent chance of miscarriage
Over 45: 50 percent chance of miscarriage
• Around one woman in every 100 has recurrent miscarriages. This is roughly three times the incidence expected by chance, suggesting that there may be a specific reason for their losses .
• However, for some people, no underlying problem can be found and their miscarriages may be due to chance alone .
• When miscarriages remain unexplained, there is still a 75 percent chance that, with the benefit of supportive care, a successful pregnancy can be achieved in the future .
1. NHS Choices. Miscarriage – Overview. Available at: www.nhs.uk/Conditions/Miscarriage/Pages/Introduction.aspx (2012, accessed 25 November 2012).
2. McLaughlin Centre, Institute of Population Health, University of Ottawa. Facts sheets – Spontaneous abortion. Available at: www.emcom.ca/health/abortion.shtml (accessed 25 November 2012).
3. Kallen B. The epidemiology of human reproduction. Boca Raton: CRC Press; 1988.
4. Royal College of Obstetricians and Gynaecologists. Early miscarriage: information for you. Patient Information Sheet. London: RCOG, 2008. Available as a PDF at: www.rcog.org.uk/files/rcog-corp/Early%20Miscarriage.pdf (accessed 26 November 2012).
5. Regan L, Braude PR, Trembath PL. Influence of past reproductive performance on risk of spontaneous abortion. BMJ 1989;299(6698):541–5.
6. NHS Choices. Miscarriage – Causes. Available at: www.nhs.uk/Conditions/Miscarriage/Pages/Causes.aspx (2012, accessed 25 November 2012).
7. Royal College of Obstetricians and Gynaecologists. Couples with recurrent miscarriage: What the RCOG guideline means for you. London: RCOG, 2004. Also available at: www.rcog.org.uk/files/rcog-corp/uploaded-files/PICouplesWithRecurrentMiscarriages2004.pdf (2004, accessed 25 November 2012).
8. Clifford K, Rai R and Regan L. Future pregnancy outcome in unexplained recurrent first trimester miscarriage. Human Reproduction (Oxford, England) 1997;12(2):387–9.
In this section
Premature birth statistics