| Stillbirth | |
|---|---|
| Classification and external resources | |
Ultrasonography is often used to diagnose stillbirth. |
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| ICD-10 | P95 |
| MedlinePlus | 002304 |
| eMedicine | topic list |
| MeSH | D050497 |
A stillbirth occurs when a fetus has died in the uterus. A wide variety of definitions exist.[1] The Australian definition specifies that fetal death is termed a stillbirth after 20 weeks gestation or the fetus weighs more than 400 grams (14 oz). Once the fetus has died, the mother may or may not have contractions and undergo childbirth. The term is often used in distinction to live birth or miscarriage. Most stillbirths occur in full-term pregnancies.
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The causes of a large percentage of human stillbirths remain unknown, even in cases where extensive testing and autopsy have been performed. A rarely used term to describe these is sudden antenatal death syndrome or SADS, a phrase coined by Cacciatore & Collins in 2000.[2]
In cases where the cause is known, some possibilities of the cause of death are:
Sometimes a pregnancy is terminated deliberately during a late phase, for example for congenital anomaly. UK law requires these procedures to be registered as "stillbirths".[4]
It is unknown how much time is needed for a fetus to die. Fetal behavior is consistent and a change in the fetus' movements or sleep-wake cycles can indicate fetal distress.[3] A decrease or cessation in sensations of fetal activity may be an indication of fetal distress or death, though it is not entirely uncommon for a healthy fetus to exhibit such changes, particularly near the end of a pregnancy when there is considerably little space in the uterus for the fetus to move about. Still, medical examination, including a nonstress test, is recommended in the event of any type of any change in the strength or frequency of fetal movement, especially a complete cease; most midwives and obstetricians recommend the use of a kick chart to assist in detecting any changes. Fetal distress or death can be confirmed or ruled out via fetoscopy/doptone, ultrasound, and/or electronic fetal monitoring. If the fetus is alive but inactive, extra attention will be given to the placenta and umbilical cord during ultrasound examination to ensure that there is no compromise of oxygen and nutrient delivery.
When the umbilical cord is constricted (q.v. "accidents" above), the fetus experiences periods of hypoxia, and may respond by unusually high periods of kicking or struggling, to free the umbilical cord. These are sporadic if constriction is due to a change in the fetus' or mother's position, and may become worse or more frequent as the fetus grows. Extra attention should be given if mothers experience large increases in kicking from previous childbirths, especially when increases correspond to position changes.[5]
As many of the causes are unknown or untreatable, prevention is difficult. Symptoms of bacterial infection, such as from a dental abscess, in pregnant women may also include unusual periods of incoherence and symptoms of shock, and should be treated by a physician immediately. High blood pressure, diabetes and drug use should be regulated with physician's advice. Umbilical cord constriction may be identified and observed by ultrasound.
Research published in the Journal of the American Medical Association in 2011 found a number of maternal factors associated with stillbirth. Among them: being age 40 or older, having diabetes, having a history of addiction to illegal drugs, being overweight or obese, and smoking cigarettes in the three months before getting pregnant. [6]
An in utero stillbirth does not usually present an immediate health risk to the woman and labour will usually begin spontaneously after two weeks, so the woman may choose to wait and birth the fetal remains vaginally. After two weeks, the woman is at risk of developing blood clotting problems, and labor induction is recommended at this point. In many cases, the woman will find the idea of carrying the dead fetus emotionally traumatizing and will elect to be induced. Caesarean birth is not recommended unless complications develop during vaginal birth.
Stillbirth is a relatively common, but often random, occurrence. The mean stillbirth rate in the United States is approximately 1 in 115 births, which is roughly 26,000 stillbirths each year, or on an average one every 20 minutes. In Australia,[7] England, Wales, and Northern Ireland, the rate is approximately 1 in every 200 births, in Scotland 1 in 167. (From The National Statistical Office and other sources.) Many stillbirths occur at fullterm to apparently healthy mothers, and a postmortem evaluation reveals a cause of death in only about 40% of autopsied cases.[8]
In developing countries, where medical care can be of low quality or unavailable, the stillbirth rate is much higher.
In Australia any stillborn weighing more than 400 grams, or more than 20 weeks in gestation, must have its birth registered.[9]
In Austria a stillbirth is defined as birth of a child of at least 500g weight without vital signs, i.e. blood circulation, breath or muscle movements.
Beginning in 1959, "the definition of a stillbirth was revised to conform, in substance, to the definition of fetal death recommended by the World Health Organization." [10] The definition of "fetal death" promulgated by the World Health Organization in 1950 is as follows:
In Germany a stillbirth is defined as birth of a child of at least 500g weight without blood circulation or breath. Details for burial are varying in the federal states.[12]
In Ireland, stillbirths must be registered as such. A stillbirth is legally defined as a child weighing at least 500 grammes, or having reached a gestational age of at least 24 weeks.[13]
Throughout the United Kingdom, stillbirths must be registered by law. The Stillbirth Definition Act (1992) states: "any ‘child’ expelled or issued forth from its mother after the 24th week of pregnancy that did not breathe or show any other signs of life should be registered as a stillbirth."[14] In England and Wales, this must be done within 42 days and a Stillbirth Certificate is issued to the parent(s).[15] In Scotland, this must be done within 21 days.[16]
In the United States, there is no standard definition of the term 'stillbirth'.[11] The Centers for Disease Control and Prevention collects statistical information on "live births, fetal deaths, and induced termination of pregnancy" from 57 reporting areas in the United States. Each reporting area has different guidelines and definitions for what is being reported; many do not use the term "stillbirth" at all. The federal guidelines suggests (at page 1) that fetal death and stillbirth can be interchangeable terms. The CDC definition of "fetal death" is based on the definition promulgated by the World Health Organization in 1950 (see section above on Canada). Researchers are learning more about the long term psychiatric sequelae of traumatic birth and believe the effects may be intergenerational [17]
The federal guidelines recommend reporting those fetal deaths whose birth weight is over 12.5 oz (350g), or those more than 20 weeks gestation. Forty-one areas use a definition very similar to the federal definition, thirteen areas use a shortened definition of fetal death, and three areas have no formal definition of fetal death. Only 11 areas specifically use the term 'stillbirth', often synonymously with late fetal death, however they are split between whether stillbirths are "irrespective of the duration of pregnancy", or whether some age or weight constraint is applied. A movement in the U.S. has changed the way that stillbirths are documented through vital records. Previously, only the deaths were reported. However 27 states have enacted legislation that offers some variation of a birth certificate as an option for parents who choose to pay for one MAB Legislative Page [MAB legislative page]
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