A miscarriage is the natural death of an embryo in the womb. It takes place in the early stages of prenatal development prior to fetal viability (the stage of potential independent survival). Among women who know they are pregnant, the miscarriage rate is roughly 15-20% and it is the most common complication of early pregnancy in humans.
The bleeding may come and go over several days. However, light vaginal bleeding is relatively common during the first trimester of pregnancy (the first 12 weeks) and does not necessarily indicate a miscarriage.
Bleeding during pregnancy may be referred to as a threatened miscarriage. Of women who seek clinical treatment for bleeding during pregnancy, about half will miscarry. Symptoms other than bleeding are not statistically related.
Miscarriage may be detected during an ultrasound exam, or through serial human chorionic gonadotropin (HCG) testing. Women pregnant from assisted reproductive technology methods, and women with a history of aborting, may be monitored closely and so detection is sooner than women without such monitoring.
It is estimated about half of early miscarriages will be fully expelled naturally. Several medical options exist for managing documented nonviable pregnancies that have not been expelled naturally, such as medicinal treatment or a dilation and curettage (D&C) procedure.
An ERPC, or evacuation of retained products of conception, may be performed to remove the remains of a pregnancy and the placental tissue from the uterus.
Therefore, in the case of an autoimmune-induced miscarriages the woman's body attacks the growing fetus or prevents normal pregnancy progression.
Further research also has suggested that autoimmune disease may cause genetic abnormalities in embryos which in turn may lead to miscarriage. As an example, Celiac disease increases the risk of miscarriage by an odds ratio of approximately 1.4.
In recurrent miscarriage, various tests are indicated to identify any underlying cause. Vitamin supplementation has not been found to be effective to prevent miscarriage.
If the bleeding is light, making an appointment to see one's doctor is recommended. If bleeding is heavy, there is considerable pain, or there is a fever, then seeking emergency medical attention is recommended.
Whilst bed rest has been advocated in the past to help ensure that a threatened pregnancy might continue, and in one study possibly helped when small subchorionic hematoma had been found on ultrasound scans, the prevailing opinion is that this is of no proven benefit.
In addition, women with bleeding in early pregnancy may attend for medical care more often than women not experiencing bleeding.
Some studies have attempted to account for this by recruiting women who are planning pregnancies and testing for very early pregnancy, although these would also not be representative of the wider population.
A systematic review found that the cumulative risk of miscarriage between 5 and 20 weeks of gestation varied from 11% to 22% in studies assessing miscarriage rates. Up to the 13th week of pregnancy, the risk of miscarriage each week was around 2%, dropping to 1% in week 14 and reducing slowly between 14 and 20 weeks.
The prevalence of miscarriage increases with the age of the mother and the father. In a Danish register-based study where the prevalence of miscarriage was 11%, the prevalence rose from 9% in women at 22 years of age to 84% by 48 years of age.
A questionnaire (GHQ-12 General Health Questionnaire) study following women having miscarried showed that more than half (55%) of them presented with significant psychological distress immediately, while 25% did at 3 months; 18% showed psychological symptoms at 6 months, and 11% at 1 year after miscarriage.
Besides the feeling of loss, a lack of understanding by others is
often important. People who have not experienced it themselves may find
it difficult to empathize
with what has occurred, and how upsetting it may be.
This may lead to unrealistic expectations of the parents' recovery. The pregnancy and the miscarriage cease to be mentioned in conversations, often because the subject is too painful. This may make the woman feel particularly isolated.
Inappropriate or insensitive responses from medical professionals can add to the distress and trauma experienced, so in some cases attempts have been made to draw up a standard code of practice.
Interaction with pregnant women and newborn children may understandably be painful for parents who have experienced miscarriage. Sometimes this makes interaction with friends, acquaintances, and family very difficult.
Some women gain emotional support and feel less alone in their grief through miscarriage self-help and support groups, and for others, online forums or message boards for pregnancy loss play a role in coping and recovery.
Signs and symptoms
The most common symptom of a miscarriage is vaginal bleeding. This can vary from light spotting or brownish discharge to heavy bleeding and bright red blood.The bleeding may come and go over several days. However, light vaginal bleeding is relatively common during the first trimester of pregnancy (the first 12 weeks) and does not necessarily indicate a miscarriage.
Bleeding during pregnancy may be referred to as a threatened miscarriage. Of women who seek clinical treatment for bleeding during pregnancy, about half will miscarry. Symptoms other than bleeding are not statistically related.
SEE ALSO: what-happens-in-womb-may-affect
Miscarriage may be detected during an ultrasound exam, or through serial human chorionic gonadotropin (HCG) testing. Women pregnant from assisted reproductive technology methods, and women with a history of aborting, may be monitored closely and so detection is sooner than women without such monitoring.
It is estimated about half of early miscarriages will be fully expelled naturally. Several medical options exist for managing documented nonviable pregnancies that have not been expelled naturally, such as medicinal treatment or a dilation and curettage (D&C) procedure.
An ERPC, or evacuation of retained products of conception, may be performed to remove the remains of a pregnancy and the placental tissue from the uterus.
Causes
Among women who know they are pregnant, the miscarriage rate is roughly 15-20%. Miscarriage may occur for many reasons, not all of which can be identified. Some of these causes include genetic, uterine, or hormonal abnormalities, reproductive tract infections, and tissue rejection. Miscarriage caused by invasive prenatal diagnosis (chorionic villus sampling (CVS) and amniocentesis) is rare (about 1%).Risk factors
Multiple pregnancy
Pregnancies of more than one fetus, i.e. twins, triplets, etc., are considered at increased risk. The more fetuses in the womb, the higher the risk.Intercurrent diseases
Several intercurrent diseases in pregnancy can potentially increase the risk of miscarriage, including:- Diabetes mellitus; The risk of miscarriage is increased in women with poorly controlled insulin-dependent diabetes mellitus. This 1998 prospective study found that the risk increased by 3.1% (over the background risk of about 16%) for each standard deviation in glycosylated haemoglobin above the normal range. The risk was not found to be significantly increased in women with good glycaemic control in early pregnancy.
- Polycystic ovary syndrome, which may increase the risk of miscarriage, but this is disputed. Two studies suggested treatment with the drug metformin significantly lowers the rate of miscarriage in women with PCOS, but the quality of these studies has been questioned. A 2006 review of metformin treatment in pregnancy found insufficient evidence of safety, and did not recommend routine treatment with the drug. In 2007 the Royal College of Obstetricians and Gynaecologists also recommended against use of the drug to prevent miscarriage.
- Hypothyroidism; Severe cases of hypothyroidism increase the risk of miscarriage. The effect of milder cases of hypothyroidism on miscarriage rates has not been established. The presence of certain immune conditions such as autoimmune diseases is associated with a greatly increased risk. The presence of anti-thyroid autoantibodies is associated with an increased risk with an odds ratio of 3.73 and 95% confidence interval 1.8–7.6.
- Vertically transmitted infections; Certain vertically transmitted infections (such as rubella and chlamydia) increase the risk.
Therefore, in the case of an autoimmune-induced miscarriages the woman's body attacks the growing fetus or prevents normal pregnancy progression.
Further research also has suggested that autoimmune disease may cause genetic abnormalities in embryos which in turn may lead to miscarriage. As an example, Celiac disease increases the risk of miscarriage by an odds ratio of approximately 1.4.
Prevention
Prevention of miscarriage is mainly based on avoiding or mitigating any risk factors of it. Currently there is no known way to prevent an impending miscarriage. Identifying the cause of the miscarriage may help prevent it from happening again in a future pregnancy.In recurrent miscarriage, various tests are indicated to identify any underlying cause. Vitamin supplementation has not been found to be effective to prevent miscarriage.
Management
Bleeding during early pregnancy is the most common symptom of both impending miscarriage and of ectopic pregnancy. Pain does not strongly correlate with the former, but is a common symptom of ectopic pregnancy. Typically, in the case of blood loss, pain, or both, transvaginal ultrasound is performed. If a viable intrauterine pregnancy is not found with ultrasound, serial βHCG tests should be performed to rule out ectopic pregnancy, which is a life-threatening situation.If the bleeding is light, making an appointment to see one's doctor is recommended. If bleeding is heavy, there is considerable pain, or there is a fever, then seeking emergency medical attention is recommended.
Whilst bed rest has been advocated in the past to help ensure that a threatened pregnancy might continue, and in one study possibly helped when small subchorionic hematoma had been found on ultrasound scans, the prevailing opinion is that this is of no proven benefit.
Methods
No treatment is necessary for a diagnosis of complete miscarriage (so long as ectopic pregnancy is ruled out). In cases of an incomplete miscarriage, empty sac, or missed abortion there are three treatment options:- With no treatment (watchful waiting), most of these cases (65–80%) will pass naturally within two to six weeks. This path avoids the side effects and complications possible from medications and surgery, but increases the risk of mild bleeding, need for unplanned surgical treatment, and incomplete miscarriage.
- Medical management usually consists of using misoprostol (a prostaglandin, brand name Cytotec) to encourage completion of the natural process. About 95% of cases treated with misoprostol will complete within a few days.
- Surgical treatment is the fastest way to complete the process. It also shortens the duration and heaviness of bleeding, and avoids the physical pain associated with the miscarriage. In cases of repeated spontaneous abortions, D&C is also the most convenient way to obtain tissue samples for karyotype analysis (cytogenetic or molecular), although it is also possible to do with expectant and medical management, including the following techniques:
-
- Vacuum aspiration, sometimes referred to as dilation and evacuation (D&E), uses aspiration to remove uterine contents through the cervix.
- Dilation and curettage (D&C), which involves dilation (widening/opening) of the cervix and surgical removal of part of the lining of the uterus and/or contents of the uterus by scraping and scooping (curettage). D&C has a higher risk of complications compared to non-surgical treatment, including risk of injury to the cervix (e.g. cervical incompetence) and uterus, perforation of the uterus, and potential scarring of the intrauterine lining (Asherman's syndrome). This is an important consideration for women who would like to have children in the future and want to preserve their fertility and reduce the chance of future pregnancy complications.
In delayed miscarriage
In delayed miscarriage (also called missed abortion), the Royal Women's Hospital recommendations of management depend on the findings in ultrasonography:- Gestational sac greater than 30-35mm, embryo larger than ~25mm (corresponding to 9+0 weeks of gestational age): Surgery is recommended. It poses a high risk of pain and bleeding with passage of products of conception. Alternative methods may still be considered.
- Gestational sac 15-35mm, embryo smaller than 25mm (corresponding to between 7 and 9+0 weeks of gestational age): Medication is recommended. Surgery or expectant management may be considered.
- Gestational sac smaller than 15-20mm, corresponding to a gestational age of less than 7 weeks: Expectant management or medication is preferable. The products of conception may be difficult to find surgically with a considerable risk of failed surgical procedure.
In incomplete miscarriage
In incomplete miscarriage, the Royal Women's Hospital recommendations of management depend on the findings in ultrasonography:- Retained products of conception smaller than 15mm: Expectant management is generally preferable. There is a high chance of spontaneous expulsion.
- Retained products of conception measuring between 15 and 20mm: Medical or expectant management are recommended. Surgery should only be considered upon specific indication.
- At retained products of conception measuring over 35 to 50mm, the following measures are recommended:
-
- Administration of misoprostol to hasten passage of products of conception.
- Admission to inpatient care for observation for a few hours or overnight until the majority of the products of conception has passed and bleeding subsided.
- After apparent failure of misoprostol, a gynecologic examination should be done prior to considering surgical evacuation of the uterus or the patient leaving the hospital.
In addition, women with bleeding in early pregnancy may attend for medical care more often than women not experiencing bleeding.
Some studies have attempted to account for this by recruiting women who are planning pregnancies and testing for very early pregnancy, although these would also not be representative of the wider population.
A systematic review found that the cumulative risk of miscarriage between 5 and 20 weeks of gestation varied from 11% to 22% in studies assessing miscarriage rates. Up to the 13th week of pregnancy, the risk of miscarriage each week was around 2%, dropping to 1% in week 14 and reducing slowly between 14 and 20 weeks.
The prevalence of miscarriage increases with the age of the mother and the father. In a Danish register-based study where the prevalence of miscarriage was 11%, the prevalence rose from 9% in women at 22 years of age to 84% by 48 years of age.
Effects
Although a woman generally physically recovers from a miscarriage quickly, some struggle to recover emotionally.A questionnaire (GHQ-12 General Health Questionnaire) study following women having miscarried showed that more than half (55%) of them presented with significant psychological distress immediately, while 25% did at 3 months; 18% showed psychological symptoms at 6 months, and 11% at 1 year after miscarriage.
This may lead to unrealistic expectations of the parents' recovery. The pregnancy and the miscarriage cease to be mentioned in conversations, often because the subject is too painful. This may make the woman feel particularly isolated.
Inappropriate or insensitive responses from medical professionals can add to the distress and trauma experienced, so in some cases attempts have been made to draw up a standard code of practice.
Interaction with pregnant women and newborn children may understandably be painful for parents who have experienced miscarriage. Sometimes this makes interaction with friends, acquaintances, and family very difficult.
Some women gain emotional support and feel less alone in their grief through miscarriage self-help and support groups, and for others, online forums or message boards for pregnancy loss play a role in coping and recovery.
