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.

Pregnancy, Normal


Related Terms

  • Conception
  • Gestation
  • Parturition

Specialists

  • Family Physician
  • Obstetrician/Gynecologist

Comorbid Conditions

Factors Influencing Duration

Factors influencing length of duration include mother's age at delivery, pre-existing conditions, and the presence of complications during delivery.

Medical Codes

ICD-9-CM:
650 - Pregnancy, Normal Delivery in a Completely Normal Case
V22.0 - Supervision of Normal First Pregnancy
V22.1 - Supervision of Other Normal Pregnancy

Overview

Pregnancy is the condition of having a developing embryo or fetus in the body as the result of the union of an ovum and spermatozoon (conception). Pregnancy can occur anytime after a female begins menstruating (menarche) until she reaches menopause. However, most pregnancies occur in women ages 15 to 40 years. Pregnancies before the age of 15 and after the age of 35 have an increased risk of complications.

The first indication of a pregnancy usually is a missed menstrual period. Laboratory tests or home pregnancy test kits check for human chorionic gonadotropin (hCG) in the woman’s serum or urine; hCG is a hormone produced by the placenta. After confirmation of the pregnancy, the physician, with information from the mother, can determine an approximate date of birth. The length of pregnancy averages 270 days from fertilization but normally is counted from the first day of menses prior to conception (approximately 284 days). Thus, the gestational age of the fetus is two weeks less than the number of weeks a woman is considered pregnant.

The growth and development of the fetus is affected by many aspects of the mother’s health: nutritional status; use of drugs, alcohol and cigarettes; use of prescribed medications, herbal remedies, and dietary supplements; medical conditions; age at time of pregnancy; and prenatal care.

Source: Medical Disability Advisor



Diagnosis

History: A complete medical history should be obtained, including medical conditions; medication use (prescription, over-the-counter, supplements); diet; use of alcohol, tobacco, and illicit drugs; both family and menstrual history (age of menarche, usual menstrual pattern, date of onset of last menses, contraceptive use, history of irregular menses); and history of previous pregnancies. Many women miss a menstrual period before they suspect pregnancy. Early symptoms may include tender, swollen breasts, nausea, vomiting, frequent urination, and fatigue.

Physical exam: The exam may reveal enlargement of the uterus on bimanual examination, softening of the uterus and cervix (Hegar’s sign) at 6 weeks, bluish color of the vagina (Chadwick’s sign) at 8 to 10 weeks, and enlargement of the breasts. At 10 to 12 weeks, fetal heart tones can be heard through a special stethoscope. The uterus may be palpable low in the abdomen by 12 weeks.

Tests: Pregnancy can be confirmed through laboratory tests or home test kits that check for hCG in serum or urine. Over-the-counter or home pregnancy test kits can detect hCG in urine and become positive 9 to 12 days after conception. hCG can be detected in the serum in 5% of pregnant women 5 days after conception and in over 98% of pregnant women by 11 days after conception. Serum hCG tests have a low false positive rate of 0.01% to 2%. A false positive test is caused by substances in the woman’s body such as antibodies, rheumatoid factor, or proteins that interfere with the test. False negative tests usually occur with urine samples and usually are due to interference from medications, dilute urine samples, or errors in following testing directions.

Other initial testing may be done to screen for conditions that may affect the health of the mother and fetus. Urinalysis screens for urinary tract infections and kidney problems. Complete blood count (CBC) tests for anemia, infection, and other blood problems. Antibody testing looks for syphilis and rubella (German measles) antibodies and blood group and Rh typing identifies blood group antigens. Individuals at risk for diabetes receive a glucose tolerance test. Additional tests may be done to screen for hepatitis B, toxoplasmosis, and HIV. Cervical cultures may be done to rule out infection.

Ultrasound reveals the age of the fetus, presence of multiple fetuses, abnormal physical development of the fetus, and location of the placenta. Ultrasound carries no known risk to the woman or her fetus. Few studies have been able to prove that ultrasound is absolutely necessary, but it has produced two positive results: fewer pregnancies go past their due dates, and women carrying fetuses with anomalies can make decisions about termination earlier in the pregnancy. Ultrasound can be done at any time, but it is most useful during the second trimester between weeks 18 and 20; a second ultrasound can be done at 23 to 28 weeks.

Prenatal diagnosis of congenital malformations and genetic disorders has increased with the development of accurate testing methods. Testing is often recommended for women who: (1) are age 35 or older; (2) have a history of parental consanguinity; (3) have a personal or parental history of a child with a chromosomal abnormality (e.g., Down syndrome, male relatives with Duchenne muscular dystrophy, severe hemophilia); (4) have experienced recurrent miscarriages; (5) has type 1 diabetes mellitus, epilepsy, or myotonic dystrophy; (6) has been exposed to certain medications, environmental hazards, or viral infections (e.g., rubella, cytomegalovirus).

Measurement of alpha-fetoprotein (AFP) levels in maternal blood serum screens for neural tube defects such as absence of all or part of the brain (anencephaly) and protrusion of part of the spinal cord through a gap in the spinal column which usually results in loss of voluntary movement in the lower body (spina bifida). AFP is a protein made by the fetus’s liver. If the fetus's spinal cord has not developed correctly, increased amounts of AFP may leak into the mother's bloodstream. Elevated levels of AFP in the maternal bloodstream can also occur with gestational diabetes, twins, intrauterine growth retardation, increased gestational age, and in pregnancies complicated by bleeding. Low levels of AFP in the mother’s bloodstream may suggest the presence of chromosomal abnormalities such as Down syndrome. Testing is most sensitive at a gestational age of 16 to18 weeks but can be performed anywhere between 15 and 22 weeks of gestation. At 15 to 20 weeks, maternal serum levels of AFP, hCG, and estriol can be measured. Each of these substances is a marker for potential fetal abnormalities. Checking the levels of these markers simultaneously increases screening sensitivity.

Analysis of the amniotic fluid (amniocentesis) that surrounds the developing fetus, is used to detect fetal genetic abnormalities in pregnant women over age 35 or in those whose family history puts them at high risk for certain genetic defects. It is usually performed between weeks 14 and 20 of the pregnancy. Under ultrasound guidance, a long needle is passed through the mother’s lower abdomen into the uterus, and a small amount of fluid is withdrawn. The fetal cells that have been shed into the fluid are analyzed for chromosomal problems (e.g., Down syndrome), and the fluid is analyzed for abnormally high level of AFP. Later in the pregnancy the test can determine the maturity of the fetus's lungs or if there is Rh incompatibility between fetus and mother. The procedure carries an increased risk of miscarriage and maternal Rh sensitization.

Chorionic villus sampling is another form of invasive testing for chromosomal abnormalities and genetic defects. Small pieces of the placenta are removed through a catheter inserted into the uterus under ultrasound guidance. The primary advantage of chorionic villus sampling is that the procedure can be performed at 10 to 12 weeks gestation, whereas amniocentesis is performed at 14 to 20 weeks gestation. The risk of miscarriage with chorionic villus sampling is 2% to 3% higher than for amniocentesis. There is also a small risk of injury to the developing fetus’ limbs.

Percutaneous umbilical cord sampling is used after 16 weeks gestation for rapid chromosome analysis as well as evaluation of fetal metabolism and fetal blood abnormalities. Guided by images on ultrasound, a doctor inserts a needle into the mother’s abdomen and withdraws a sample of the baby’s blood from the umbilical cord. Because this is an invasive procedure, percutaneous umbilical cord sampling carries risks for both mother and fetus.

If the mother is of African origin, a test for sickle cell anemia may be ordered. Jewish mothers of eastern European ancestry (Ashkenazi Jews) and French Canadians should be tested for the Tay-Sachs gene.

Source: Medical Disability Advisor



Treatment

Regular prenatal visits to a physician or maternity clinic are essential for a healthy, safe pregnancy, delivery, and postpartum recovery.

For an uncomplicated pregnancy, visits usually are scheduled every 4 weeks during the first and second trimester and every 2 weeks during the third trimester. At week 36, visits are increased to weekly until delivery. A mother who goes past her due date may be seen 2 to 3 times a week.

At each prenatal visit, blood pressure, weight, fundal height, and fetal heart rate are measured and recorded. Urine is tested for abnormal amounts of glucose and albumin (urinalysis).

Each mother should receive information regarding proper nutrition, exercise, sexual activity, work activity, tobacco and alcohol use, and medication restrictions. Prenatal vitamins usually are prescribed. Childbirth classes, breastfeeding instruction, and family planning should be offered.

Source: Medical Disability Advisor



Prognosis

Most individuals will deliver a healthy child and have a complete, uncomplicated recovery.

Source: Medical Disability Advisor



Rehabilitation

Rehabilitation for normal pregnancy can be re-cast in terms of working during pregnancy. Most women can continue to work in jobs to which they are acclimated during most of pregnancy (Gabbe).

While exposure to toxic substances that might harm the fetus should logically be avoided, no one has published a list of occupations or jobs that should be avoided by pregnant women based on known exposures.

Exercise during pregnancy is to some degree analogous to the physical demands of work during pregnancy. Exercise in general in healthy women with normal pregnancies is strongly recommended. Both the American College of Obstetricians and Gynecologists and the Society of Obstetricians and Gynaecologists of Canada have published guidelines that strongly recommend routine exercise during pregnancy ("Guidelines"; Davies).

These guidelines state that exercise has been shown to have beneficial effects on maternal health and pregnancy outcome. Theoretical concerns—about pregnant women being at increased risk of fall due to their altered centers of gravity, and being at increased risk of sprains and strains due to hormonally mediated increased ligamentous laxity—have not been substantiated by data.

Although exercise during pregnancy usually is safe, several things should be avoided. A pregnant woman should avoid holding her breath during exercise (Valsalva maneuver) because this restricts oxygen flow to the placenta. Exercising while lying on the back (supine position) after the first trimester is not recommended because this decreases the cardiac output to the fetus. Activities such as skiing or horseback riding, in which falls could harm the mother or fetus, should be avoided.

In any workout, the woman should pay special attention to strengthening the lower back and pelvic floor muscles (Kegel exercises). In addition to strength training, a cardiovascular workout of walking or riding a bicycle is recommended. If a specific exercise causes pain or discomfort, it should be discontinued and an alternative exercise initiated. According to the American College of Obstetricians and Gynecologists (ACOG), exertion during pregnancy should be governed by the woman’s own good judgment—she can push herself as much or as little as she is comfortable.

Both guidelines contain absolute and relative contraindications to exercise during pregnancy, and logically these conditions would be potential contraindications to moderate, heavy, or very heavy work.

Absolute Contraindications to Exercise During Pregnancy:
• Uncontrolled type 1 diabetes, thyroid disease, or other serious cardiovascular, respiratory, or systemic disorder
• Growth restricted fetus
• Incompetent cervix/cerclage (prior miscarriages)
• Multiple gestation at risk for premature labor
• Persistent second or third trimester bleeding
• Placenta previa after 26 weeks gestation
• Premature labor during the current pregnancy
• Ruptured membranes
• Pregnancy induced hypertension
• Preeclampsia

Relative Contraindications to Exercise During Pregnancy:
• Severe anemia (Hemoglobin < 100 g/L)
• Unevaluated maternal cardiac arrhythmia
• Mild/moderate cardiovascular or respiratory disorder
• Chronic bronchitis
• Poorly controlled type I diabetes
• Extreme morbid obesity
• Extreme underweight (body mass index <12), malnutrition or eating disorder
• History of extremely sedentary lifestyle
• Intrauterine growth restriction in current pregnancy
• Poorly controlled hypertension/preeclampsia
• Orthopaedic limitations
• Poorly controlled seizure disorder
• Poorly controlled thyroid disease
• Heavy smoker

The concerns with work and pregnancy relate to hypertension/preeclampsia, premature delivery, and delivery of small—for gestational age—children (intrauterine growth retardation). In recent years, more women are working during pregnancy, and more women are working to within 1 month of delivery.

In the meta-analysis of 29 published studies (Mozurkewich), statistically significant but very minor risks were found for some work activities and pregnancy outcome. Mozurkewich estimates that one preterm birth might be prevented for each . . .
• 27 to 80 women who discontinue prolonged standing;
• 23 to 171 women who discontinue shift or night work;
• 36 to 65 women who discontinue physically demanding work;
• 12 to 32 women who modify cumulative work fatigue factors.

Thus, based on this meta-analysis, work would be safe for most pregnant women, but work restrictions could be imposed by the woman’s physician if there were any indication of any complications occurring during the monitoring of pregnancy.

A systematic review by Bonzini (2007) found 53 studies on work and/or physical activity on preterm delivery, 34 studies on low birth weight, and 9 on preeclampsia. For pre-term delivery and small for gestational age the larger and more complete studies were less positive and risk was only modest or not present. This review concluded there was not significant evidence to justify mandatory activity or work restrictions.

In summary, work during pregnancy is usually a question of whether a woman can safely continue to work at a job to which she is accustomed. The risk of continuing to work is small, and most of the conditions that might be caused by continuing to work can be monitored by the woman’s physician. If any of the absolute or relative contraindications to exercise during pregnancy are present or develop, the pregnant woman’s physician will logically impose work restrictions.

In the absence of these problems, during an uncomplicated normal pregnancy, the following durations mark the time at which the pregnant woman should stop that type of work activity:
• Sedentary - at onset of labor or 40 weeks gestation
• Light - at 38 weeks gestation
• Moderate - at 32 weeks gestation
• Heavy - at 26 weeks gestation
• Very Heavy - at 20 weeks gestation

If complications occur, transfer to a sedentary job, elimination of strenuous work (especially heavy lifting), elevation of legs during the day, shortened work hours, and extended leave may be required.

Please refer to other MDA monographs for work after spontaneous miscarriage and cases of induced abortion.

Source: Medical Disability Advisor



Complications

Complications from pregnancy range from minor annoyances (e.g., constipation, varicose veins) to conditions that threaten the life of mother and/or fetus (e.g., severe nausea and vomiting [hyperemesis gravidarum], hypertension and associated symptoms [pre-eclampsia], convulsions resulting from hypertension and associated symptoms [eclampsia], third trimester bleeding, placenta previa, Rh sensitization, and premature labor).

HELLP syndrome is a severe form of pre-eclampsia. Its name comes from symptoms associated with the condition: disruption in the integrity of red blood cells (Hemolysis), Elevated Liver enzymes, and Low Platelet counts. Typical symptoms include headaches, blurred vision, nausea, vomiting, tingling in the extremities (paresthesias), and band-like pain around the upper abdomen. If an expectant mother has HELLP syndrome, immediate delivery is recommended if the pregnancy has advanced to 34 weeks or more. Before 34 weeks, treatment decisions are based on the stability of the mother’s condition, the fetal gestational age, fetal lung maturity, and overall fetal condition. In some cases, bed rest and other measures are instituted to allow continuation of the pregnancy to 34 weeks; in other situations, immediate delivery may be recommended (Sibai).

Group B Streptococcal (GBS) bacteria are found in the vagina of up 10% to 30% of pregnant women (ACOG). Most women do not experience any symptoms from the presence of the bacteria; however, 1 to 2 babies out of every 100 develop an infection from the bacterium. The infection can cause inflammation of the baby’s blood, lungs, brain, or spinal cord, and leads to death in about 5% of infected infants. Approximately 10,000 cases of neonatal streptococcal septicemia occur each year in the US (Duff). Screening for GBS is performed by taking a swab of the mother’s vagina between 35 and 37 weeks of pregnancy and sending it to the lab for culture. All women who are positive for GBS should be treated with antibiotics during labor except those who undergo Cesarean section.

Source: Medical Disability Advisor



Ability to Work (Return to Work Considerations)

Work following pregnancy and delivery should take in the following considerations. Return to work may be based on federal and state laws that allow the mother to have approved medical leave to permit adjustment to motherhood and bonding with the infant. Thus medical issues may not determine the duration of time off work following delivery.

On a medical basis, most women can return to most jobs within 4 to 6 weeks of vaginal delivery, and within 8 weeks following cesarean delivery.

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:

  • What is individual's age?
  • Was pregnancy confirmed by laboratory testing?
  • Can fetal heart tones be heard?

Regarding treatment:

  • Does individual see her physician regularly?
  • Has individual received appropriate prenatal counseling? Has she incorporated it into her daily routine?

Regarding prognosis:

  • Is individual exercising as directed by her physician?
  • Is employer able to accommodate any necessary restrictions?
  • Does individual have any conditions that may affect her pregnancy outcome?
  • Has individual experienced any complications such as hyperemesis gravidarum, pre-eclampsia, eclampsia, constipation, various varicose veins, tumors of the uterus, third trimester bleeding, placenta previa, Rh sensitization, premature labor or HELLP syndrome?
  • Did individual have a normal vaginal delivery?
  • Does individual have postpartum depression?

Source: Medical Disability Advisor



References

Cited

ACOG. "Group B Streptococcus and Pregnancy." American Congress of Obstetricians and Gynecologists (ACOG). 2003. 23 Dec. 2008 <http://www.acog.org/publications/patient_education/bp105.cfm>.

Artal, R. , M. O'Toole, and S. White. "Guidelines of the American College of Obstetricians and Gynecologists for Exercise During Pregnancy and the Postpartum Period." British Journal of Sports Medicine 37 1 (2003): 6-12.

Bonzini, M. , D. Coggon, and K. T. Palmer. "Risk of Prematurity, Low Birthweight and Pre-Eclampsia In Relation to Working Hours and Physical Activities: A Systematic Review." Occupational and Environmental Medicine 228-243.

Davies, G. A. , et al. "Exercise in Pregnancy and the Postpartum Period." Journal of Obstetrics and Gynaecology Canada (JOGC) 25 6 (2003): 516-529.

Duff, Patrick. "Maternal and Perinatal Infection - Bacterial." Obstetrics: Normal and Problem Pregnancies. Eds. Steven G. Gabbe, Jennifer R. Niebyl, and Joe L. Simpson. 5th ed. New York: Churchill Livingstone Elsevier, 2007.

Gabbe, Steven G., et al., eds. Obstetrics - Normal and Problem Pregnancies. 5th ed. New York: Churchill Livingstone, Inc., 2007.

Mozurkewich, Ellen L. , et al. "Working Conditions and Adverse Pregnancy Outcome: A Meta-Analysis." Obstetrics and Gynecology 95 4 (2000): 623-635.

Sibai, Baha M. "Hypertension." Obstetrics: Normal and Problem Pregnancies. Eds. Steven G. Gabbe, Jennifer R. Niebyl, and Joe L. Simpson. 5th ed. New York: Churchill Livingstone Elsevier, 2007.

General

Haywood, Brown L. "Normal Pregnancy." The Merck Manual of Home Health Care. Ed. Robert S. Porter. Online ed. Whitehouse Station: Merck Research Laboratories, 2007.

Porter, Robert S., ed. "Prenatal Diagnostic Testing." The Merck Manual of Home Health Care. Online ed. Whitehouse Station: Merck Research Laboratories, 2007.

Simpson, Joe L., and Lucas Otano. "Prenatal Genetic Diagnosis." Obstetrics: Normal and Problem Pregnancies. Eds. Steven G. Gabbe, Jennifer R. Niebyl, and Joe L. Simpson. 5th ed. New York: Churchill Livingstone Elsevier, 2007.

Trupin, Suzanne R. "Common Pregnancy Complaints and Questions." eMedicine. Eds. Andrea Witlin, et al. 27 Oct. 2004. Medscape. 3 Nov. 2008 <http://emedicine.com/med/topic3238.htm>.

Source: Medical Disability Advisor






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