A miscarriage is the loss of a baby during the first 23 weeks of pregnancy.
According to the baby charity, Tommy’s, as many as 50% of all pregnancies end in miscarriage - most often before a woman misses a menstrual period or even knows she is pregnant. About 15% of recognised pregnancies will end in a miscarriage.
Up to 80% of miscarriages occur within the first three months of pregnancy. Less often they occur after 20 weeks gestation, termed late miscarriages.
What are the symptoms of miscarriage?
Symptoms of a miscarriage include:
If you're pregnant and experience the symptoms listed above, seek medical advice straight away. You’ll be advised whether to attend your GP practice, antenatal clinic, or accident and emergency (A&E).
What causes miscarriage?
The causes of miscarriage are not well understood. Most of the miscarriages that occur in the first trimester of pregnancy are caused by chromosomal abnormalities in the baby. Chromosomes are tiny structures inside the cells of the body that carry many genes. Genes determine all of a person’s physical attributes, such as sex, hair and eye colour, and blood type. Most chromosomal problems occur by chance and are not related to the mother's or father's health.
Miscarriages are also caused by a variety of other factors, including:
- Exposure to environmental and workplace hazards such as high levels of radiation or toxic agents
- Hormonal problems
- Uterine abnormalities
- Incompetent cervix - the cervix begins to widen and open too early, in the middle of pregnancy, without signs of pain or labour
- Lifestyle factors such as smoking, drinking alcohol or using illegal drugs
- Disorders of the immune system, including lupus
- Severe kidney disease
- Congenital heart disease
- Uncontrolled diabetes
- Thyroid disease
- Certain medications
- Severe malnutrition
In addition, women may be at increased risk of miscarriage based on their age. Studies show that the risk of miscarriage is 12% to 15% for women in their 20s and rises to about 25% for women at the age of 40. The increased incidence of chromosomal abnormalities contributes to the age-related risk of miscarriage.
Note: there is no proof that stress or physical or sexual activity causes miscarriage.
Sometimes, treatment of a mother's chronic illness can improve the chances of a successful pregnancy.
How is a miscarriage diagnosed and treated?
Your doctor or midwife may perform a pelvic examination and an ultrasound test to confirm the miscarriage. If the miscarriage is complete and the uterus is clear, then no further treatment is usually required. Occasionally, the uterus is not completely emptied, so a dilation and curettage (D&C) procedure is performed. During this procedure, the cervix is dilated and any remaining foetal or placental tissue is gently removed from the uterus. As an alternative to a D&C, certain medications can be given to cause your body to expel the contents in the uterus. This option may be more suitable for someone who wants to avoid surgery and whose condition is otherwise stable.
If a miscarriage was not confirmed, but you had symptoms of a miscarriage, rest is often recommended. You may be admitted to the hospital overnight for observation. Blood tests to determine the amount of a pregnancy hormone ( hCG) is checked to monitor the health of your baby. When the bleeding stops, usually you will be able to continue with your normal activities. If the cervix is dilated, you may be diagnosed with an incompetent cervix and a procedure to close the cervix (called cerclage) may be performed.
Blood tests, genetic tests or medication may be necessary if a woman has more than three miscarriages in a row - called recurrent miscarriage. Some diagnostic procedures used to evaluate the cause of recurrent miscarriage include: endometrial biopsy (a procedure involving the removal of a small amount of tissue from the lining of the uterus for study under a microscope), hysterosalpingogram (an X-ray of the uterus and fallopian tubes), hysteroscopy (a test in which the doctor views the inside of the uterus with a thin, telescope-like device inserted through the vagina and cervix), and laparoscopy (a surgical procedure in which the doctor views the pelvic organs with a lighted device).