Abortion, Spontaneous

Also found in: Dictionary, Thesaurus, Legal, Encyclopedia.
Related to Abortion, Spontaneous: threatened abortion, induced abortion, missed abortion

Abortion, Spontaneous

DRG Category:770
Mean LOS:2 days
Description:SURGICAL: Abortion with Dilation and Curettage, Aspiration, Curettage, or Hysterotomy
DRG Category:779
Mean LOS:1.9 days
Description:MEDICAL: Abortion without Dilation and Curettage

Spontaneous abortion (SAB) is defined as the termination of pregnancy from natural causes before the fetus is viable. Other terms include miscarriage or spontaneous early pregnancy loss. Viability is defined as 20 to 24 weeks’ gestation or a fetal weight of more than 500 g. SABs are a common occurrence in human reproduction, occurring in approximately 15% to 22% of all pregnancies. If the abortion occurs very early in the gestational period, the ovum detaches and stimulates uterine contractions that result in its expulsion. Hemorrhage into the decidua basalis, followed by necrosis of tissue adjacent to the bleeding, usually accompanies the abortion. If the abortion occurs later in the gestation, maceration of the fetus occurs; the skull bones collapse, the abdomen distends with blood-stained fluid, and the internal organs degenerate. In addition, if the amniotic fluid is absorbed, the fetus becomes compressed and desiccated.

There are four types of SABs, classified according to symptoms (Table 1), as well as a threatened abortion. The four types of actual abortion are inevitable, incomplete, complete, and missed. A threatened abortion occurs when there is slight bleeding and cramping very early in the pregnancy; about 50% of women in this category abort. An inevitable abortion occurs when the membranes rupture, the cervix dilates, and bleeding increases. An incomplete abortion occurs when the uterus retains parts of the products of conception and the placenta. Sometimes the fetus and placenta are expelled, but part of the placenta may adhere to the wall of the uterus and lead to continued bleeding. A complete abortion occurs when all the products of conception are passed through the cervix. A missed abortion occurs when the products of conception are retained for 2 months or more after the death of the fetus. Signs and symptoms of these five types of abortion involve varying degrees of vaginal bleeding, cervical dilatation, and uterine cramping.

Types of SABs
Table 1. Types of SABs
ThreatenedSlightMild crampingNoNo
InevitableModerateModerate crampingYesNo
IncompleteHeavySevere crampingYesYes
CompleteDecreased; slightMild crampingNoYes
MissedNone; slightNoneNoNo


The majority of SABs are caused by chromosomal abnormalities that are incompatible with life; the majority also have autosomal trisomies. Maternal infections, such as Mycoplasma hominis, Ureaplasma urealyticum, syphilis, HIV, group B streptococci, and second-trimester bacterial vaginosis, increase the risk for an SAB. Inherited disorders or abnormal embryonic development resulting from environmental factors (teratogens) may also play a role. A woman’s occupation, such as a hair stylist, may also be a factor in SAB if she is exposed to teratogens. Unfavorable environmental factors also include interpersonal violence, as women who are in abusive relationships have a 50% higher chance of pregnancy loss.

Patients who are classified as habitual aborters (three or more consecutive SABs) usually have an incompetent cervix—that is, a situation in which the cervix is weak and does not stay closed to maintain the pregnancy. Another reason for habitual abortions may be antiphospholipid antibodies and polycystic ovarian disease.

Genetic considerations

It is estimated that 50% or more of fetuses spontaneously aborted during the first trimester have significant chromosomal abnormalities. Slightly more than 50% of these are trisomies, 19% are monosomy X, and 23% are polyploidies (multiples of a complete set of chromosomes). About 9% of aborted fetuses and 2.5% of stillbirths are due to trisomy 13, 18, or 21. Infants with trisomy 13 or 18 rarely survive the perinatal period. These abnormalities result from chromosomal nondisjunction during meiosis, a phenomenon that itself appears to have some genetic influences. Monogenetic factors include mutations in pregnancy-specific glycoproteins (PSGs), cytochrome c oxidase (SCO2), NALP7, methylenetetrahydrofolate reductase (MTHFR), prothrombin (F2), and skewed X-choromosome inactivation, which can all cause spontaneous abortions. Deficiencies of A4GALT or B3GALT3 can also cause hemolytic disease of the newborn and spontaneous abortion via anti-P/P(k) antibodies.

Gender, ethnic/racial, and life span considerations

More than 80% of abortions occur in the first 12 weeks of pregnancy. SABs are more common in teens (12%), elderly primigravidas (26%), and those women who engage in high-risk behaviors, such as drug and alcohol use or multiple sex partners. The incidence of abortion increases if a woman conceives within 3 months of term delivery.

Global health considerations

International rates of SAB vary, likely dependent on how data are collected. In an English study, researchers found that ultrasound screening at 10 to 13 weeks of gestation revealed a 2.8% rate of pregnancy failure. Approximately 13% of all pregnancy-related deaths are due to abortion worldwide, whereas in the United States, about 4% of pregnancy-associated deaths are related to induced and spontaneous abortions.



Obtain a complete obstetric history. Determine the date of the last menstrual period to calculate the fetus’s gestational age. Vaginal bleeding is usually the first symptom that signals the onset of a spontaneous abortion. Question the patient as to the onset and amount of bleeding. Inquire further about a small gush of fluid, which indicates a rupture of membranes, although at this early point in gestation, there is only a small amount of amniotic fluid expelled. Ask the patient to describe the duration, location, and intensity of any pain. Although it is a sensitive topic, ask the patient about the passage of fetal tissue. If possible, the patient should bring the tissue passed at home into the hospital because sometimes laboratory pathological analysis can reveal the cause of the abortion. With a missed abortion, early signs of pregnancy cease; thus, inquire about nausea, vomiting, breast tenderness, urinary frequency, and leukorrhea (white or yellow mucous discharge from the vagina).

Physical examination

Elevated temperature above 100.4°F indicates maternal infection. Pain varies from a mild cramping to severe abdominal pain, depending on the type of abortion; pain can also occur as a backache or pelvic pressure. In addition, pallor, cool and clammy skin, and changes in the level of consciousness are symptoms of shock. Examine the patient’s peripad for vaginal blood loss and determine if any tissue has been expelled. Sometimes tissue can be observed at the introitus, but do not perform a vaginal examination if that situation occurs.


Assess the patient’s emotional status, as well as that of the baby’s father and other family members. Often this hospital admission is the first one for the patient, and it may cause anxiety and fear. The father may withhold expressing his grief, feeling that he needs to “be strong” for the mother.

Diagnostic highlights

General Comments: Most of the time, diagnosis of SAB is made based on patient symptoms and the documentation of a positive pregnancy test.

TestNormal ResultAbnormality With ConditionExplanation
Human chorionic gonadotropin (hCG)Negative < 5 mIU/mL> 5 mIU/mL, increases as the gestation progresseshCG normally is not present in nonpregnant women
Ultrasound (transvaginal, transabdominal)Positive fetal heartbeat; growth within normal limitsHeartbeat absent; gestational sac appears shriveled or shrinkingUsed to diagnose a missed abortion
Red blood cells; hemoglobin; hematocrit4.2–5.4 mL/mm3; 12–16 g/dL; 37%–47%These three values will decrease several hours after significant blood loss has occurredWith active bleeding, red blood cells are lost

Other Tests: Blood type and crossmatch, white blood cells; habitual aborters should also undergo additional testing to rule out causes other than an incompetent cervix (thyroid-stimulating hormone, mid–luteal phase serum progesterone measurement, hysterosalpingogram, and screening for lupus anticoagulant).

IU = International units

Primary nursing diagnosis


Anticipatory grieving related to an unexpected pregnancy outcome


Grief resolution


Grief work facilitation; Active listening; Presence; Truth telling; Support group

Planning and implementation


Threatened abortions are treated conservatively with bedrest at home, although there is no evidence to support bedrest as altering the course of a threatened abortion. Acetaminophen is prescribed for mild pain. Patients are instructed to abstain from intercourse for at least 2 weeks following the cessation of bleeding. Approximately 50% of patients who are diagnosed with a threatened abortion carry their pregnancies to term. Inevitable and incomplete abortions are considered obstetric emergencies. Intravenous (IV) fluids are started immediately for fluid replacement, and narcotic analgesics are administered to decrease the pain. Oxytocics, when given IV, help decrease the bleeding. With any type of abortion, it is critical to determine the patient’s blood Rh status. Any patient who is Rh-negative is given an injection of an Rho(D) immune globulin (RhoGAM) to prevent Rh isoimmunization in future pregnancies, but there is little evidence that RhoGAM administration is necessary for first-trimester losses. To determine the patient’s response to treatment, monitor the patient’s vital signs, color, level of consciousness, and response to fluid replacement.

A dilation and curettage (D&C) is usually indicated. This procedure involves dilating the cervix and scraping the products of conception out of the uterus with a curette. The nurse’s role in this procedure is to explain the procedure to the patient and family, assist the patient to the lithotomy position in the operating room, perform the surgical prep, and support the patient during the procedure.

A D&C is not indicated in the case of a complete abortion because the patient has passed all tissue. Bleeding and cramping are minimal. Monitor the patient for complications, such as excessive bleeding and infection. With a missed abortion, the physician can wait for up to 1 month for the products of conception to pass independently; however, disseminated intravascular coagulation (DIC) or sepsis may occur during the wait. Clotting factors and white blood cell counts should be monitored during this waiting time. The physician can remove the products of conception if an SAB does not occur.

Pharmacologic highlights

Medication or Drug ClassDosageDescriptionRationale
Oxytocin (Pitocin)10–20 U IV after passage of tissueOxytocicStimulates uterine contractions to decrease postpartum bleeding
RhoGAM120 mg (prepared by blood bank)Immune serumPrevents Rh isoimmunizations in future pregnancies; given if mother is Rh negative and infant is Rh positive


Monitor for shock in patients who are bleeding. Nursing interventions are complex because of the profound physiological and psychological changes that a woman experiences with a spontaneous abortion. Monitor emotional status. Emotional support of this patient is very important. In cases of a threatened abortion, avoid offering false reassurance because the patient may lose the pregnancy despite taking precautions. Phrases such as “I’m sorry” and “Is there anything I can do?” are helpful. It is not helpful to say, “If the baby had lived, he or she would probably be mentally retarded” or “You are young; you can get pregnant again.” Inform the patient of perinatal grief support groups.

Expect the patient to experience very mild uterine cramping and minimal vaginal bleeding. Patients become very drowsy from the anesthesia; ensure that a call light is within easy reach and side rails are up for safety. Assist the patient to the bathroom; syncope is possible because of anesthesia and blood loss. Continue to support the patient emotionally. Patients should be offered the opportunity to see the products of conception.

Evidence-Based Practice and Health Policy

Smart, C.J., & Smith, B.L. (2013). A transdisciplinary team approach to perinatal loss. American Journal of Maternal Child Nursing, 38(2), 110–114.

  • A team approach, which includes nurses, physicians, social workers, and chaplains, is encouraged to promote comprehensive patient-centered care and enhanced education and support of families experiencing spontaneous abortion and perinatal loss.
  • Assessment of both the families and their care providers is necessary to explore what the pregnancy and subsequent loss means for the family and how to best support care providers as they provide support to grieving families.
  • Suggestions for targeted care delivery models should include multiple processes that address automatic chaplain referrals from all points of entry into the hospital, policies to ensure respectful handling of the remains, flow sheets specific to caring for families experiencing fetal demise, consent forms that provide comprehensive options regarding burial and cremation and allow informed decision-making, ongoing opportunities for perinatal grief support, and care providers who are trained in loss and grief.

Documentation guidelines

  • Amount and characteristics of blood loss, passage of fetal tissue, severity and location of pain, vital signs
  • Signs of hypovolemic shock (pallor; cold, clammy skin; change in level of consciousness)
  • Patient’s (and father’s) emotional response to losing the pregnancy

Discharge and home healthcare guidelines

Use extreme caution not to make the patient feel guilty about the cause of the SAB; however, it is important that she be made aware of factors that might contribute to the occurrence of an SAB (such as cigarette smoking, alcohol and drug usage, exposure to x-rays or environmental teratogens). Preconceptual care should be encouraged should the patient decide to become pregnant again.

Teach the patient to notify the physician of an increase in bleeding, return of painful uterine cramping, malodorous vaginal discharge, temperature greater than 100.4°F, or persistent feelings of depression.

home care.
Teach the patient to avoid strenuous activities for a few days. Encourage the patient to use peripads instead of tampons for light vaginal discharge to decrease the likelihood of an infection. Explain that the patient should avoid intercourse for at least 1 week and then use some method of birth control until a future pregnancy can be discussed with the physician. Follow-up is suggested. A phone call to the patient on her due date will demonstrate support and provide an outlet for her to express her grief. Provide contact information for a support group. Explain that help is available because women who experience spontaneous abortions are at high risk for depression.

Diseases and Disorders, © 2011 Farlex and Partners