Miscarriage and Stillbirth

Pregnancy loss is a surprisingly common occurrence, but often goes unrecognized, unregistered, or unacknowledged. Medically, fetal death represents a challenge to the worldwide goal of reducing child mortality. Psychosocially, the death of a child before birth, because it represents neither the entry of a new person into society nor the departure of a recognized member of the social order, presents unique challenges to the grieving parents.

Definitions

Miscarriage, or spontaneous abortion, is defined by the World Health Organization (WHO) as a fetal [Page 738]death in early pregnancy. Stillbirth is defined as the death of a fetus late in pregnancy, during the perinatal period, from 22 weeks gestational age through 7 days postpartum. Individual countries rather arbitrarily define the gestational age at which a pregnancy termination is classified as either a miscarriage, early stillbirth (typically 20–28 weeks gestation), or late stillbirth (after 28 weeks). Some industrialized countries classify death at 16 weeks gestation as a stillbirth. If the gestational age is unknown, a birth weight of 500 grams is often used to make the distinction between miscarriage and stillbirth. Stillbirths are also often classified as antepartum (before the onset of labor) or intrapartum (during labor). This variation in the classification of miscarriage or stillbirth makes epidemiological monitoring and intervention difficult.

Rates

About 15#x0025; to 20#x0025; of pregnancies result in miscarriage, the most common complication of early pregnancy. The rate is much higher if one includes pregnancies that end within six weeks of the last menstrual period, often before a woman is aware of the pregnancy. Eighty percent of miscarriages occur within the first trimester.

Approximately 5#x0025; of first pregnancies end in miscarriage. Most women who miscarry go on to have successful pregnancies, but about 1#x0025; of women have recurrent (more than three) miscarriages. The risk of subsequent miscarriage or stillbirth increases with each prior stillbirth or complicated pregnancy. The rates of twin and multiple births have increased in the past two decades, associated with growing use of assisted reproductive technologies. The risk of stillbirth is four times greater in multiple pregnancies than in pregnancies with just one fetus.

The WHO notes a worldwide incidence of stillbirth at 3.9 million, with about 26#x0025; of those stillbirths occurring during the delivery of a mature fetus. These figures are generally thought to be underestimates because most births in developing countries occur in the home and information is not reported. The rate of stillbirth in developing nations is 10 times greater than in the United States. The most recent figures reported by the WHO estimates the stillbirth rate in the United States as 3/1,000, on a par with the figures reported for Canada, Australia, and much of Europe.

Causes

Miscarriages may be the result of chromosomal abnormalities, progesterone deficiencies, uterine malformations or infections, or uncontrolled diabetes. However, most causes of miscarriage are unknown and thought to be unpreventable.

It is difficult to obtain data on the causes of stillbirth because of a lack of uniformity in protocols for classification of stillbirth and the declining rates of autopsies. Where protocols are available, it is found that the most common causes of stillbirth between 24 and 27 weeks' gestational age are infection, placental problems, or fetal malformations. Between 25#x0025; and 60#x0025; of stillbirths are due to unknown causes. Death during labor is rare in the developed world, but in developing countries as many as 1 in 100 babies die during delivery. It is presumed that access to good obstetric care could prevent these deaths, as well as late stillbirths due to maternal/fetal infection.

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