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Sedentary Work Exerting up to 10 pounds (4.5 kg) of force occasionally and/or a negligible amount of force frequently or constantly to lift, carry, push, pull, or otherwise move objects, including the human body. Sedentary work involves sitting most of the time, but may involve walking or standing for brief periods of time. Jobs are sedentary if walking and standing are required only occasionally and other sedentary criteria are met.

Light Work Exerting up to 20 pounds (9.1 kg) of force occasionally and/or up to 10 pounds (4.5 kg) of force frequently, and/or negligible amount of force constantly to move objects. Physical demand requirements are in excess of those for Sedentary Work. Light Work usually requires walking or standing to a significant degree. However, if the use of the arm and/or leg controls requires exertion of forces greater than that for Sedentary Work and the worker sits most the time, the job is rated Light Work.

Medium Work Exerting up to 50 (22.7 kg) pounds of force occasionally, and/or up to 25 pounds (11.3 kg) of force frequently, and/or up to 10 pounds (4.5 kg) of forces constantly to move objects.

Heavy Work Exerting up to 100 pounds (45.4 kg) of force occasionally, and/or up to 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Very Heavy Work Exerting in excess of 100 pounds (45.4 kg) of force occasionally, and/or in excess of 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Job Classification

In most duration tables, five job classifications are displayed. These job classifications are based on the amount of physical effort required to perform the work. The classifications correspond to the Strength Factor classifications described in the United States Department of Labor's Dictionary of Occupational Titles. The following definitions are quoted directly from that publication.

Sedentary Work Exerting up to 10 pounds (4.5 kg) of force occasionally and/or a negligible amount of force frequently or constantly to lift, carry, push, pull, or otherwise move objects, including the human body. Sedentary work involves sitting most of the time, but may involve walking or standing for brief periods of time. Jobs are sedentary if walking and standing are required only occasionally and other sedentary criteria are met.

Light Work Exerting up to 20 pounds (9.1 kg) of force occasionally and/or up to 10 pounds (4.5 kg) of force frequently, and/or negligible amount of force constantly to move objects. Physical demand requirements are in excess of those for Sedentary Work. Light Work usually requires walking or standing to a significant degree. However, if the use of the arm and/or leg controls requires exertion of forces greater than that for Sedentary Work and the worker sits most the time, the job is rated Light Work.

Medium Work Exerting up to 50 (22.7 kg) pounds of force occasionally, and/or up to 25 pounds (11.3 kg) of force frequently, and/or up to 10 pounds (4.5 kg) of forces constantly to move objects.

Heavy Work Exerting up to 100 pounds (45.4 kg) of force occasionally, and/or up to 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Very Heavy Work Exerting in excess of 100 pounds (45.4 kg) of force occasionally, and/or in excess of 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Premature Labor


Text Only Home | Graphic-Rich Site | Overview | Risk and Causation | Diagnosis | Treatment | Prognosis | Differential Diagnosis | Specialists | Comorbid Conditions | Complications | Factors Influencing Duration | Length of Disability | Duration Trends | Ability to Work | Failure to Recover | Medical Codes | References

Medical Codes

ICD-9-CM:
644.03 - Early or Threatened Labor, Antepartum Condition or Complication
644.10 - Threatened Labor, Other, Unspecified as to Episode of Care or Not Applicable
644.13 - Threatened Labor, Other, Antepartum Condition or Complication
644.21 - Early Onset of Delivery, Delivered, with or without Mention of Antepartum Conditions

Related Terms

  • Early Onset of Delivery
  • Early or Threatened Labor
  • Preterm Labor
  • Threatened Premature Labor

Overview

Premature or preterm labor refers to the onset of labor contractions before 37 weeks of gestation. In preterm labor, contractions are intense and frequent enough to result in the cervical dilation and effacement that normally precedes birth. Unlike the irregular nature of false labor contractions (Braxton-Hicks contractions), premature labor contractions can dilate the cervix and lead to premature delivery.

Although the exact cause usually is unknown, many factors have been associated with premature labor. Mechanical factors may be involved such as an overly distended uterus that occurs in multiple gestation (i.e., twins, triplets, quadruplets), an excess of amniotic fluid (polyhydramnios), a weakened cervix (cervical incompetence), defects of the uterus or the presence of fibroids, or infection and inflammation of the cervix. The mother's health status also may play a role. Preterm labor can be influenced by hormonal changes resulting from fetal distress or maternal stress and chronic conditions such as diabetes, asthma, or high blood pressure (hypertension). Managing preterm labor requires identifying the factors associated with the preterm birth, evaluating the status of the fetus, prolonging gestation if possible, and careful monitoring of the mother and fetus to achieve the optimum neonatal outcome.

Incidence and Prevalence: Premature labor is a complication in approximately 12.5% of all pregnancies; preterm births occurring after 32 weeks gestation are the majority of cases; births before 32 weeks are only about 2% of all preterm births (Iams 669). Preterm births, especially those before 32 weeks, are the leading cause of infant illness (morbidity) and death (mortality) in the US (Iams 670).

Source: Medical Disability Advisor



Causation and Known Risk Factors

Although specific risk factors are not always identified, pregnant women with certain conditions or history may be at increased risk for preterm labor, including those with hypertension, inadequate or excessive weight gain during pregnancy, chronic medical conditions (e.g., diabetes, heart disease, asthma), infections (including systemic, vaginal, genital or urinary tract infections, and amnionitis); anemia; pre-eclampsia; short interval between pregnancies; previous preterm labor; cervical incompetence; prior Rh incompatibility (isoimmunization when an Rh-negative mother gives birth to an Rh-positive fetus); multiple pregnancies (multiparity or grand multiparity in women with 7 or more births); ovulation induction via assisted reproductive technologies; overdistended uterus (polyhydramnios, multiple gestation); history of infertility; prior abdominal or gynecologic surgical complications; uterine anomalies such as müllerian fusion defects; fibroids; retained IUD; and cervical trauma as a result of elective abortion or surgery for cervical dysplasia (Ross).

Nonexistent or poor prenatal care can increase risk of preterm labor. A history of drug abuse, smoking, or alcohol consumption also can contribute to increased risk of preterm labor.

Risk factors for premature labor in an otherwise uncomplicated pregnancy include standing for periods greater than 4 hours without a break, lifting weights greater than 25 lb (12 kg) more than 50 times per week, working more than 36 hours per week or more than 10 hours per shift, and high stress. Estimates are the 15-40% of premature deliveries are genetic (Muglia).

The risk of premature labor is greatest in women younger than 15 or older than 35. Black women have twice the rate of premature labor than other racial groups; 17.8% of preterm births are to non-Hispanic blacks, 11.9% to Hispanics, and 11.3% to whites (Iams 673). Women of low socioeconomic status also are at increased risk of premature labor, believed due to lack of prenatal care and proper nutrition and not a factor in racial differences. Fetal factors that predispose a woman to preterm labor and/or threatened abortion may include the presence of birth defects (congenital anomalies) and intrauterine death [See Miscarriage].

Source: Medical Disability Advisor



Diagnosis

History: Symptoms of premature labor may include frequent contractions (more than 4 per hour), cramping, pelvic pressure, excessive vaginal discharge, and backache. Premature rupture of membranes often occurs with the onset of premature labor. The individual’s obstetric and health history is important to the management of preterm labor, especially a history of prior preterm deliveries or complications of pregnancies.

Physical exam: The woman may present with contractions, cervical dilation (>1 centimeter), cervical thinning (effacement) exceeding 80%, ruptured membranes, or a change in cervical dilation or effacement as noted in serial examinations (Iams 673). The individual also will be assessed for uterine irritability or abnormalities and for general physical and mental health status. Examination will include assessment for any conditions that threaten the health of either the mother or fetus, including acute maternal conditions such as kidney disease (pyelonephritis), pneumonia or asthma, peritonitis, or hypertension, and obstetric conditions such as pre-eclampsia, placental abruption, placenta previa, or chorioamnionitis, which may indicate that delivery is the only course.

Tests: Nitrazine paper testing may be performed to evaluate pH levels in order to rule out ruptured membranes. In cases associated with hemorrhage, laboratory tests may include complete blood count (CBC) and hematologic workup (hematocrit, hemoglobin, prothrombin time [PT], partial thromboplastin time [PTT]). Blood chemistries may be performed, including electrolytes, kidney and liver function profiles, and serum glucose testing if the mother’s health status warrants or if suppression of contractions (tocolysis) is a possible treatment. A urine culture and sensitivity may be done to rule out urinary tract infection. Ultrasound scanning is used to determine fetal size, position, and placental location. Transvaginal ultrasound is used to assess cervical integrity and length as indicators of risk. Continuous uterine monitoring may be necessary, including possible home uterine activity monitoring (HUAM). Amniocentesis may be performed to obtain fluid for assessing fetal maturity. A fetal fibronectin test is used primarily to rule out premature labor during the subsequent 14 days.

Source: Medical Disability Advisor



Treatment

Treatment depends on whether labor is allowed to continue. Critical factors in this decision include gestational age, fetal maturity, and the amount of dilation and effacement of the cervix. The likelihood of survival of the fetus is reduced if significant complications are present, such as infection, hypertension, acute obstetric conditions, hemorrhage in the mother, or fetal distress, which may suggest that labor should not be stopped.

Standard treatment to prolong gestation usually involves bed rest with the individual lying on the left side (left lateral decubitus position). Treatment also includes sedation, increased fluid intake (hydration), antibiotics, fetal heart rate monitoring, uterine monitoring, and antenatal corticosteroids to accelerate lung maturation of the fetus.

In more urgent situations, labor often can be stopped with drugs (pharmacologic intervention). Uterine contractions may be inhibited with beta-mimetic adrenergic agents, magnesium sulfate, prostaglandin synthetase inhibitors, and calcium channel blockers. However, these agents carry potential morbidity, and are used only when risks and benefits of use are established for the individual situation. If labor can be stopped, the individual may have the cervix bound (cervical cerclage). If the labor cannot be stopped, the individual is transferred to a hospital with a neonatal intensive care unit for immediate care of a preterm infant. Internal fetal monitoring is done to determine the most effective mode of delivery.

Regular prenatal visits to a physician or maternity clinic are essential for a healthy, safe pregnancy, delivery, and postpartum period. Evaluation of risk for preterm birth is essential early in pregnancy and can help prevent premature labor in women at high risk.

Source: Medical Disability Advisor



Prognosis

Premature labor can be successfully treated with bed rest alone if maternal or fetal complications are not present. The addition of sedation and hydration can prolong gestation for two or more weeks. Administration of tocolytic agents between 24 and 33 weeks' gestation is able to delay delivery for 48 hours, allowing the use of glucocorticoids to prevent respiratory distress syndrome in the pre-term fetus; however, tocolytics carry a high risk of morbidity and neonatal mortality if used at 24 weeks or less (Ross). Clinical studies have shown that the use of tocolytic agents only slightly improves the prognosis compared to bed rest and hydration, which do not increase morbidity. If labor cannot be stopped, a premature infant will be delivered. Survival of the fetus is greatly influenced by the gestational age; for example, survival of a 24-week fetus is 40%, survival of a 30-week fetus is 93% and survival of a 34-week fetus is 97% (Ross). Long-term morbidities that may affect an infant born before 26-weeks gestation include chronic lung disease, neurosensory impairment, cerebral palsy, reduced cognition and motor performance, attention deficit disorders, and vision and hearing problems (Iams).

Source: Medical Disability Advisor



Differential Diagnosis

  • Braxton Hicks contractions (false labor)

Source: Medical Disability Advisor



Specialists

  • Gynecologist
  • Obstetrician/Gynecologist

Source: Medical Disability Advisor



Comorbid Conditions

Source: Medical Disability Advisor



Complications

Complications include maternal infection, hemorrhage, stress, and depression from delivering a premature infant, along with increased morbidity and mortality of the premature infant. Death and disability are more likely in infants born before 32 weeks gestation; prematurity is responsible for more than 70% of fetal and neonatal deaths, and conditions such as visual and hearing impairment, chronic lung disease, cerebral palsy, and delayed childhood development (Iams 670).

Source: Medical Disability Advisor



Factors Influencing Duration

Length of disability is influenced by how far the pregnancy has progressed before labor begins, methods used to stop premature labor, response to treatment, and presence of bleeding, infection, or other complications. Bed rest may be required until delivery.

Source: Medical Disability Advisor



Ability to Work (Return to Work Considerations)

Possible work restrictions and accommodations may include extended leave or placement on short-term disability. If the individual is allowed to return to work, shortened work hours, increased rest breaks, and transfer to sedentary duties with no lifting and limited standing may be required.

Source: Medical Disability Advisor



Failure to Recover

If an individual fails to recover within the expected maximum duration period, the reader may wish to consider the following questions to better understand the specifics of an individual's medical case.

Regarding diagnosis:

  • Has diagnosis of premature labor been confirmed?
  • Is there a history of prior preterm delivery?
  • Have confirmatory tests such as transvaginal ultrasound, fetal fibronectin, or amniocentesis been done?
  • What underlying conditions may have caused contractions to begin?
  • What is the gestational age of the fetus? Was lung maturity evaluated?
  • What neonatal morbidity and mortality was expected given the gestational age and other indicators?
  • Were any conditions present that endangered the health of mother or fetus?

Regarding treatment:

  • Was it determined that labor should be stopped in this case?
  • Did treatment include bed rest with the woman lying on the left side?
  • Can contributing underlying conditions be treated?
  • Did regimen include appropriate sedation, increased hydration, antibiotics, fetal heart rate monitoring, uterine monitoring, and antenatal corticosteroids to accelerate fetal lung maturation?
  • If the situation was more urgent, were drugs able to stop the uterine contractions?
  • If the labor could not be stopped, was individual transferred to a hospital with a neonatal intensive care unit?
  • Was internal fetal monitoring done to determine the most effective mode of delivery?

Regarding prognosis:

  • Did individual respond to treatment? Was premature labor stopped?
  • If the labor could not be stopped, was there a premature delivery?
  • Did mother or infant experience any complications that may affect recovery?

Source: Medical Disability Advisor



References

Cited

Iams, Jay, and Roberto Romero. "Preterm Birth." Obstetrics - Normal and Problem Pregnancies. Eds. Steven G. Gabbe, et al. 4th ed. New York: Churchill Livingstone, Inc., 2002. MD Consult. Elsevier, Inc. <http://mdconsult.com>.

Muglia, Louis J. , and Michael Katz. "The Enigma of Spontaneous Preterm Birth." New England Journal of Medicine 362 6 (2010): 529-535.

Ross, Michael G., and Robert D. Eden. "Preterm Labor." eMedicine. Eds. Suzanne Trupin, et al. 31 Jul. 2009. Medscape. 21 Sep. 2009 <http://emedicine.medscape.com/article/260998-overview>.

Source: Medical Disability Advisor