Miscarriage

Miscarriage
Specialty	Obstetrics

Miscarriage or spontaneous abortion is the natural or accidental termination of a pregnancy at a stage where the embryo or the fetus is incapable of surviving, generally defined at a gestation of prior to 20 weeks. Miscarriages are the most common complication of pregnancy. The term "abortion" refers to any terminated pregnancy, deliberately induced or spontaneous, although in common parlance it refers specifically to active termination of pregnancy.

Experience

The most common symptoms of a miscarriage are bleeding and cramping. Bleeding alone is not necessarily a sign of impending miscarriage, and may be the result of a small area of bleeding behind the placenta. Indeed, between 20-25% of women who go on to have a healthy baby will have some bleeding in the first trimester.

In the event that miscarriage is suspected, two tests can be used to determine whether a woman is indeed having a miscarriage. The first test is pelvic ultrasound. A gestational sac will be present on ultrasound approximately 5 weeks after the last menstrual period, and an embryo can usually be seen after approximately 6 weeks. By 7 weeks a fetal heartbeat can be seen. Ultrasound may show an embryo that has stopped developing, or an empty gestational sac. Alternatively, the presence of a viable embryo with an appropriate heart rate raises the possibility that the pregnancy will survive.

The second test is a quantitative Human chorionic gonadotropin (HCG) test. In a healthy pregnancy, the HCG level should double approximately every 48 hours. If the level is not doubling appropriately, it can be a sign of impending miscarriage. Measuring the HCG level has the added advantage of providing information about pregnancies before they can be seen on ultrasound. Additionally, it provides information about the possibility of an ectopic pregnancy. This can be difficult to distinguish from an impending miscarriage.

In some cases a miscarriage will proceed spontaneously, resulting in the expulsion of all pregnancy tissue from the uterus. Often, though, the uterus is unable to expel all the tissue and the amount of bleeding and cramping can increase significantly. In these cases, a dilation and curretage is necessary.

Prevalence

Miscarriages occur more often than most people think. About 25% of women will experience one in their lives. Up to 78% of all conceptions may fail, in most cases before the woman even knows she is pregnant. A fifth of confirmed pregnancies have some bleeding occurring in the first 20 weeks and in all 15% proceed to miscarriage. After the age of 35, the risk of miscarriage increases considerably: 1 in 5 or 6. After 40, the risk increases to 1 in 3, and after 45 it is 1 in 2.

Terminology

If a pregnant woman has vaginal bleeding, she is said to have a "threatened abortion," many patients with first trimester bleeding will be found to have a subchorionic hematoma and do well. In about half such bleeding will progress to miscarriage.

With pain and opening of the cervix a woman is about to have an "inevitable abortion," which indicates that she has an absolute probability of miscarrying.

If some of the tissue remains in the uterus after a passing products of conception, this is called an "incomplete abortion." If the tissue in the uterus gets infected, it is a "septic abortion". In some cases the fetus dies, but the uterus does not expel the pregnancy:- this is called a "missed abortion." A "blighted ovum" pregnancy is a form of a miscarrage where the fetus either did not form, or died early, and the pregnancy consists only of trophoblastic tissue.

A specific form of a miscarriage is the ectopic pregnancy.

Forms and types

ICD-10 codes are provided where available.

Threatened abortion (O20.0)

A threatened abortion is the development of symptoms (bleeding with or without cramps or low back pain) that often suggest impending miscarriage. With such a presentation of bleeding, 50% proceed to miscarriage of the pregnancy.

Management of these patients involves an examination to assess for cervical dilatation, an ultrasound to assess fetal viability, and bedrest for the woman, though there is no scientifically-proven benefit for the latter. When a threatened abortion occurs, no hormones or medications have been shown to influence whether this will resolve or progresses to a full abortion.

Inevitable abortion

The miscarriage of a pregnancy is inevitable when any of the following symptoms are present:

• There is an obvious rupture of membranes
• An open cervix
• There is tissue in the cervix
• There is an absence of fetal heart at a ßHCG level consistent with fetal heart activity

When any of these symptoms are detected, management involves conservative observation, monitoring for heavy bleeding and sepsis, and a dilatation and curettage (D&C).

Incomplete abortion (O03.0-O06.4)

An incomplete abortion is the miscarriage of a fetus in a pregnancy when tissue has been passed, but some remains in utero. It can result in severe bleeding, infection or intrauterine scarring. Management consists of a dilation and curettage (D&C).

Septic abortion

The infection of the womb carries risk of spreading infection (septicaemia) and is a grave risk to the life of the woman. It may follow an incomplete miscarriage and previously was a problem for pregnancies that occurred if a Dalkon Shield IUD had failed in its contraception. This has been particularly associated with abortions performed in non-sterile circumstances, common where abortions are carried out illegally and/or by poorly skilled and equipped operators.

Missed abortion (O02.1)

A missed abortion is the miscarriage of a fetus in a pregnancy when the fetus has died, but remains in the uterus. Many cases of missed abortion will lead to a spontaneous abortion within days. Occasionally, a dilatation and currettage is necessary to remove the pregnancy tissue, done in reponse to the risk of maternal coagulation abnormality if the tissue remains in the uterus for several weeks.

Habitual abortion (N96)

Habitual abortion (recurrent pregnancy loss or recurrent miscarriage) is the occurrence of 3 consecutive miscarriages. The majority (85%) of women who have had two miscarriages will conceive and carry normally afterwards, so statistically the occurrence of three abortions at 0.34% is regarded as "habitual".

There are various medical conditions associated with this problem (e.g. Antiphospholipid syndrome), some of which may be corrected with medication.

Pathology

When looking for gross or microscopic pathologic symptoms of miscarriage, one looks for the products of conception. Microscopically, these include villi, trophoblast, fetal parts, and background gestational changes in the endometrium. Cytogenetic studies show that half or more of first trimester pregnancy losses have abnormal chromosome arrangements.

Timing

Most such terminations occur very early in pregnancy, during the first trimester, and many people restrict the term "miscarriage" (or early miscarriage) to early losses. Pregnancy losses in the second trimester (or late miscarriage) are much less common.
Miscarriages frequently occur so early that the woman is not even aware that she is pregnant; these are preclinical pregnancy losses.

Some women are prone to miscarry; the term "habitual abortion" is more and more replaced by "recurrent pregnancy loss" (RPL) or recurrent miscarriage and describes the condition where three consecutive pregnancies have terminated before 20 weeks gestation.

Causes

Miscarriages can occur for many reasons, not all of which can be identified. They are most frequent during the first trimester. About 30% of fertilized eggs are actually lost before the woman knows she is pregnant and may only be noticeable by slightly more important blood loss.

First trimester losses are most commonly caused by one time non-repeating genetic problems. This can be the result of an abnormal sperm, and abnormal ovum or an abnormal combination of the egg and sperm. The resulting baby does not develop properly and in some cases, the development of the embryo stops before it can be seen, a "blighted ovum". It is important to keep in mind that these are non-repeating genetic defects. Therefore, women who have had one miscarriage do not have a higher risk of having a second miscarriage.

Other possible but much less common causes include physical trauma, exposure to certain chemicals, infection, and immune factors. A number of studies have examined lifestyle factors. Thus obesity, high caffeine intake (> 300 mg/day), alcohol consumption, and use of NSAIDs have all been linked to higher miscarriage rates in general. Also women undergoing fertility therapy tend to have higher miscarriage rates.

In the US, smoking label warnings must be displayed to inform women that smoking can lead to "low birth weights."

Pregnancy losses in the second trimester may be due to fetal abnormalities, uterine malformation, cervical problems, infection, trauma, immune factors, and medical disease.

Management

• Threatened miscarriages with little blood loss or pain may be managed by seeing one's doctor the next working day to arrange an ultrasound scan to verify that the pregnancy is continuing (i.e., that a fetal heartbeat can be seen).
  • However, if the bleeding is heavy or accompanied by considerable pain, then emergency medical attention should be sought.
• If a miscarriage is complete and bleeding is contained and limited, only expectant management may be necessary.Excessive or prolonged bleeding needs medical attention. Often a dilation and curettage is indicated to remove tissue from the uterus. Tissue examination, including cytogenetic studies, are helpful to determine the cause of the pregnancy loss (but no routine investigations are undertaken for non-habitual early miscarriages in the UK).
• A miscarriage accompanied by a fever needs emergency medical attention.
• Severe lower abdominal pain may indicate an ectopic pregnancy and needs emergency medical attention.

Psychological aspects

Although a woman physically recovers from a miscarriage quickly, psychological recovery can take a long time. Women can differ a lot in this regard: some are 'over' it after a few months, others take more than a year. Still other women may feel relief or other less negative emotions.

For the women who do go through a process of grief, it is often as if the baby had been born but died. How short a time the child in her womb has lived may not matter for the feeling of loss. From the moment a woman becomes aware that she is pregnant she can start to bond with her unborn child. When the child turns out not to be viable, dreams, fantasies and plans for the future are disturbed roughly.

Besides the feeling of loss, a lack of understanding by others is often important. People who have not experienced a miscarriage themselves may find it hard to empathise with what has occurred and how upsetting it may be. This may lead to unrealistic expectations of the woman's recovery. The pregnancy and miscarriage are hardly mentioned anymore in conversation, often too because the subject is too painful. This can make the woman feel isolated.

Interaction with pregnant women and newborn children is often also painful for a woman who has miscarried. Sometimes this makes the interaction with friends, acquaintances and family very difficult. Immediately after a miscarriage some women do not leave home at all for fear of meeting acquaintances or pregnant women.

Some things a woman can do to deal with a miscarriage better are:

• naming the child
• keeping photos
• arranging a funeral for the child
• reading books on the subject
• talking about it
• finding others who have gone through a miscarriage
• finding professional help: although it is a natural grieving process, it may take a long time. In such cases, a psychologist or grief counselor may be of help.

See also

• Childbirth
• Stillbirth
• Premature birth

External links

• MedLine Plus: Spontaneous Abortion
• Hormones predict miscarriage risk
• Miscarriage Overview
• Coping With Loss (Excerpt from a chapter on Child-Bearing Loss in Our Bodies, Ourselves)
• Frequently asked questions about recurrent miscarriage/recurrent pregnancy loss