Preterm Labor
Preterm Labor
• Guidelines for Perinatal Care, 2012
– Preterm labor generally can be defined
as regular contractions that occur
before 37 weeks of gestation and are
associated with changes in the cervix.
Scope of the Issue
• 12.5% in 2005 (30% increase from 1981)
– slight  singleton births, significant rise
due to  in multiple gestations
– Twins 55%risk PTB, triplets 90%
• PTB causes 75% of neonatal deaths
not caused by congenital anomalies
– 1999, prematurity became leading cause
of neonatal mortality, accounts for 23% of
deaths in first month of life
South Dakota and US, 1995-2005
Preterm birth
Preterm is less than 37 completed weeks gestation.
Source: National Center for Health Statistics, final natality data.
Retrieved October 2, 2007, from www.marchofdimes.com/peristats.
South Dakota, 2005
>37 wks
32-26 wks
< 32 wks
10,143 births
1,156 births
158 births
Prematurity/LBW accounts for 8.1% of SD infant deaths
Cost of PTL/PTB
• Does not account for life-long deficits
associated w/PTB (< 32 wks)
– cerebral palsy, mental retardation, chronic lung
disease, vision and hearing loss
Etiology
• 50% of patients with preterm labor
have no risk factors
• Risk Factors
– Medical/Obstetric
– Current Pregnancy
– Demographic/Behavioral/Other
• Overall, ~20% of PTB are medically
indicated due to pregnancy complications
or health problems in mom or baby.
3 Groups with Highest Risk
• Women who have had a previous
preterm birth
• Women who are pregnant with
twins, triplets, or more
• Women with certain uterine or
cervical abnormalities
Medical Risks Predating This
Pregnancy
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Hx prior PTB (triples risk)
3 or more abortions/miscarriages
Uterine anomalies
Low pre-preg. weight for height
Parity (0 or > 4)
Pre-existing conditions (DM, HTN)
Current Pregnancy Risks
• Uterine distension (multiples,
hydramnios)
• Maternal infection (incl. untreated
vaginal infections & UTI’s)
• Incompetent cervix
• Short inter-pregnancy interval (i.e. < 6-9
months between pregnancies)
• Bleeding in 1st trimester
Current Pregnancy Risks (cont)
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Placenta previa or abruptio
Anemia
Fetal anomalies
PROM
Abdominal surgery
Demographic Risks
• Maternal Age < 17 or > 35
• Non-white
– Black - 17.5%
– Hispanic - 11.4%
– White - 11%
• Low socio-economic status
• Unmarried
• Low level education
Behavioral Risks
• Smoking ( risk by 40%)
• Poor nutrition, poor weight gain
–  risk of LBW infant by 60% and  risk PTB 60%
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Alcohol ( risk 40%)
Other substance abuse
Pre-pregnancy weight < 100 lbs
Late or no prenatal care
Occupational & environmental factors
Domestic violence
Other Risks
• Stress
• Long working hours with long periods of
standing
• Inability to rest
• Lack of social support
• However, the best predictor of having a
preterm birth is a history of preterm
delivery or prior LBW infant
– 1 prior PT delivery --- 2x risk
– 2 prior PT deliveries – 4x risk
Maternal Effects
• Psychological Stress
– Threat of Preterm Delivery
– Fear for Self and Baby
– Potential for Long-Term Bedrest
• Physical Stress
– Prolonged Bedrest
– Medications
Fetal/Neonatal Effects
• Fetal
– Tocolytics
– Risk of Birth Trauma
• Neonatal
– Intraventricular Hemorrhage (IVH)
– Respiratory Distress Syndrome (RDS)
– Patent Ductus Arteriosus (PDA)
– Necrotizing Enterocolitis (NEC)
– Other
Physiology of Labor
• Cervical Ripening
– Cervical connective tissue changes
– Cervical softening & shortening
– Prostaglandins stimulate ripening
• Uterine Contractions
– Estrogen
– Progesterone
• Prostaglandins
Preterm Labor
• Cause often related to factors that
stimulate the release of
prostaglandins
– Infection
– Uterine over-distention
– Decreased uterine blood flow
Signs/Symptoms
• Contractions q. 10 min. or more
often (may be painless)
• Low, dull backache
• Menstrual-like cramps
• Cramps with or without diarrhea
– Thigh pain
– Pelvic pressure/heavy feeling
– Abdominal/intestinal cramping
Signs/Symptoms
• Change/increase in vaginal
discharge (clear, pink, brownish)
• Leaking vaginal fluid
• Feeling baby is pushing down
• Feeling bad
• Remember, Palpate for UC’s don’t rely on EFM!
Assessment
• Diagnostic Testing
– CBC
– Urinalysis
– Cervical assessment (speculum, U/S)
– Amniocentesis (culture, L/S ratio,
Lamellar Body Count [LBC])
– Fetal Fibronectin (fFN)
– Saliva Test
Cervical Length Assessment
• Cervical length < 30 mm per ultrasound
seems to predict PTL
– Only accurate up to ~ 30 wks gestation
– After 30 wks, short cervix may not mean PTL
risk
• To compare cervical length, at least 2
ultrasounds should be done
• Expensive to do
• May be beneficial for women at risk for
PTL/PTB
Amniocentesis
• Removal of amniotic fluid via U/S for
fluid analysis (L/S ratio, cultures,
chromosomes)
• L/S – lecithin/sphingomyelin; ratio of
2.0 or higher indicates lung maturity
• PG – phosphatidtyl glycerol (if
present, indicates lung maturity)
Lamellar Body Count
• New method for testing FLM,
results in 30 minutes (L/S 4 hours)
• Can only be run on clear fluid (do
L/S if meconium or blood in fluid)
• Results interpretation:
– <20 = immature
– 21-24 = intermediate
– >25 = mature
Complications
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Miscarriage 1:300 – 1:500 (0.2 – 0.3%)
Abdominal cramps
Leakage of fluid
Spotting
Infection
Mild abdominal cramps/slight abdominal
site tenderness at needle puncture site
normal
Fetal Fibrinectin (FDA, 1995)
• A glycoprotein & major component of the
extracellular matrix of the membranes of the
amniotic sac
• Secreted from fetal membranes, found in the
junction between the chorion & the decidua
• Acts as a “glue”, binds placenta to the uterus
• Normally absent (< 50 ng/ml) from vaginal
secretions from 24-36 wks gestation.
– Levels > 50 ng/ml between 24-34 wks is predictor of PTL
Should Not Be Used for
Symptomatic Women:
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Advanced cervical dilation (>3 cm)
Rupture of amniotic membranes
Cervical cerclage
Moderate or gross vaginal bleeding
Sexual intercourse in past 24 hours
Fetal Fibrinectin
• Factors affecting accuracy
– Sexual activity w/in 24 hrs of sampling
– Cervical exam w/in 24 hrs of sampling
– Vaginal bleeding
– Intraamniotic & vaginal infections
– Use of douches
Sample Collection
• Must be collected during speculum
exam B/4 any other exam performed
(lubricating gel interferes w/test results)
• “Specimen Collection Kit” is the
only acceptable specimen collection
system
Sample Collection
• During spec exam,
• Remove swab &
lightly rotate swab
immerse Dacron tip in
across posterior fornix
buffer. Break shaft (at
of vagina (sympt.
the score) even w/top of
women) or external
the top.
cervical os (asympt.
• Align shaft w/hole in
women) for 10 sec. to
cap and push tightly.
absorb secretions
• Send at room temp to
lab
Salivary Estriol (FDA, 1998)
• Levels in maternal saliva  just prior to PTL
– Wait at least 1 hr after eating, smoking,
chewing gum, or caring for teeth/gums
– Rinse mouth with water, wait 10 min.
– Places funnel to lower lip, catch saliva
– Collect between 0900-2000 to avoid normal
night-time surges of estriol
– Level > 2.1 ng/mL is considered +
– 5 samples recommended over 10 wks
between 26 to 35 wks
Test Interpretation
• Negative predictive value high
– fFN - up to 95% (1:125 chance of delivering in 2 wks)
• Costs ~ $230
– Salivary estriol - up to 98%
• Costs ~ $90 each (x5 = $450)
• Positive predictive value low
– fFN - 25 to 40% (1:6 chance of delivering in 2 wks)
– Salivary estriol - 7 to 25%
Assessment
• Maternal
– History
– Vital Signs
– Uterine Activity
– Cervical Status
Assessment
• Fetal
– EFM
– Nonstress Test (NST)
– Biophysical Profile (BPP)
– Serial Ultrasound
Assessment
• Psychological
– Anxiety
– Stress Factors
Nursing Considerations
• Bed rest - lateral recumbent
– Benefits:  intravascular volume & uterine
blood flow,  pressure on cervix
• Uterine Status – PALPATE!!
– Q. shift, palpate to assess UCs
• Preterm Labor S/S – interventions
– Instruct what to report/what to do for ↑ UCs
• Maternal/Fetal Vital Signs
– Temp at least q. 4 hours if ROM
Interventions
• Intake/Output
– Careful I&O if on tocolytic therapy
– ↑ output may mean ↓ serum Mg levels and vice
versa
• Education
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How to palpate UCs, interventions
Fetal movement counts
Bedrest/activity restrictions
When to call provider
• Comfort Measures/Emotional
Nursing Interventions
B/4 Calling Doctor
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Make sure patient side-lying
Oral or IV hydration (unless contraindicated)
Empty bladder
Palpate UC’s
SQ, oral, or demand dose of terbutaline if
ordered
Clarify What Bedrest Order Means...
• Resting a few times a day at home
• Bed with bathroom & meal privileges
• Bed with bathroom privileges (meals in
bed side lying)
• Complete bedrest with no BRPs
• Trendelenburg with foley
• “Pelvic rest”
• Etc.
Bedrest Effects: Musculoskeletal System
• Muscle atrophy starts to occurs within 6
hours of bed rest
– Large, weight-bearing muscle groups affected
more
• Bone loss occurs
– Calcium, phosphorus, magnesium, & zinc excreted
in excessive amounts
– Great bone loss occurs in the calcaneus (largest
bone in foot), hip, and lumbar spine
• Recovery prolonged and bone loss is not
completely restored in hip & spine  may
induce early osteoporosis
Bedrest Effects: Cardiopulmonary System
• Lower extremity fluid redistributed
headway (~ 600-700 ml)
– ↑ in thoracic fluid volume, stimulates
diuresis of fluid & electrolytes
– State of hypovolemia produced
• Pulmonary changes
– Lung volume ↓, so airway resistance ↑
Cardiopulmonary Changes
• Cardiovascular changes:
– ↓ in plasma volume by 15-20%
– ↓ total blood volume 5-10%
– ↓ in CO by 25%
– HR ↑ gradually, BP remains relatively
stable
– Trendelenberg bedrest ↑ the losses
more rapidly
Recovery Cardiopulmonary
Changes
• Prolonged and varies
• Bouts of orthostatic intolerance,
fainting, ↑ heart rate, syncope, fatigue
• ↑ venous pooling in dependent body
parts producing edema, redness, and
discomfort
Metabolic & Endocrine System
• Basal metabolic rate ↓ 2-22%,
depending on length of bedrest
• Weight loss due to loss of fluid, bone,
muscle, & appetite
– Loss occurs primarily in lean rather than fatty
tissue
• Immune system – prolonged activity
restriction reported to ↓ natural killer
cells, phagocytic activity of neutrophils
& T-lymphocytes
Metabolic & Endocrine
• Dirunal rhythms unstable
– Sleep/wake cycles altered
– Quantity & quality of sleep affected
• Hormonal changes
– Alterations in insulin secretion – insulin
resistance develops  hyperglycemia
– Can happen as early as 2nd day of bedrest
– The longer the bedrest, the ↑ the
intolerance
Physiologic Effects
• Reduced sensory & social stimulation
– Too little sensory stimulation can be as
stressful as too much
• Sense of physical restriction or
confinement
• Stress compounds the complex
adverse effects of bedrest
• Affect, cognition, perception, and motor
coordination are adversely affected
Family Effects & Finances
• Fathers/partner stressed from “having
to do everything”, constant state of
worry
• Mother stressed re: leaving all the work
to family members
• Child care concerns
• Loss of maternity leave time
• Loss of pay check
Antepartum, Physiologic - Summary
• Muscle weakness
• Cardiovascular
deconditioning
• Fatigue
• Orthostatic
hypotension
• Backache
• Muscle ache
• Joint pain
• Difficulty
concentrating
• Dizziness
• Shortness of breath
• Difficulty sleeping
• Weight loss
AP, Physiologic/Psychosocial Summary
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Maternal stress
Paternal stress
Family stress
Child care problems
Financial difficulties
Depression
Anxiety
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Hostility
Mood lability
Loneliness/isolation
Boredom
Sense of confinement
Guilt
Loss of
control/autonomy
Post Partum
• Muscle weakness
• Cardiovascular
deconditioning
• Fatigue
• Orthostatic
hypotension
• Backache
• Muscle soreness
• Difficulty walking
• Difficulty
concentrating
• Dizziness
• Shortness of breath
• Prolonged recovery
• Depression
• Delay in performing
ADLs
Postpartum Symptoms After
Antepartum Bedrest
• Maternal symptoms during PP
recovery under-recognized
• In 1 study, most common symptoms
8 wks PP were extreme tiredness and
backache (Thompson et al, 2002)
Implications for Nursing
• After bedrest, assessment of
symptoms before hospital discharge is
needed, and continued assessment
may be needed beyond 6 weeks PP
• Early DC may not be advisable – need
to recover from childbirth & bed rest
Nursing Implications
• Early ambulation can help women
begin to recover from musculoskeletal & cardiovascular
deconditioning, but be careful!
– Overuse of muscles can cause muscle
tears & lead to injury & falls.
• Instruct women of s/s after bed rest:
limited strength,  fatigue, muscle
soreness, orthostatic hypotension
Nursing Implications
• Instruct woman that:
– Ambulation will restore function
– Extra help will be needed with household
chores
– Caution is needed to prevent injury & falls,
especially when using stairs
– Lingering symptoms should be reported to
care provider
– Referral to rehab program can help women
safely rebuild atrophied muscles without
injury and restore cardiovascular status.
Tocolysis
• Goals
– Inhibit contractions
– Prevent cervical change
– Prolong pregnancy
Medications - See Med Sheet
• Betamimetics (Ritodrine, Terbutaline)
• Magnesium Sulfate
• Prostaglandin Inhibitors
(Indomethacin)
• Calcium Channel Blockers (Nifedipine)
• Oxytocin Antagonists being studied
Progesterone to  Risk PTB
• Several small studies suggested that 17alpha-hydroxyprogesterone caproate (17P)
may reduce the risk of PTB
– Must be initiated between 16-20 wks in order to
decrease risk
– Weekly injections of 250 mg 17P (suppositories
also used in studies)
– Significantly reduced risk of delivery at < 37, 35,
and 32 wks gestation.
– Fewer neonatal complications (IVH, NEC, O2)
• Ideal formulation unknown (ACOG
Committee Opinion)
Antenatal Steriods
• Benefits
–  incidence of RDS
–  incidence of IVH
• Disadvantages of Multiple Courses
– Fetal Effects (adrenal suppression, cerebral
demyelinization, deleterious effect on lung growth)
– Maternal effects (increased incidence of infection,
adrenal suppression)
– Occurred with 3 or more rounds of steroids; 2
rounds might be okay, ie, early & again at 32 wks if
S/S PTL
SQ Pump
• Infrequent use – used for SQ infusion
of terbutaline (also Zofran for
hyperemesis)
• Print policy & follow step-by-step
• Notify Home Infusion – they must first
check with insurance to see if it is
covered!
• Ruth P. coordinates program
Quick-Set Infusion Set
Needle Insertion
Prep skin, then remove needle shield
and paper backing
Needle Insertion
Insert with quick “jab”, depress
opsite to seal, remove needle
Activate needle
cover to discard
Remove tubing for
showers
Prevention Strategies
• In 2003, AWHONN joined March of
Dimes in a 5-year campaign to 
awareness of PTB and to  the rate
of PTB in the US
– Will invest $75 million and raise new
funds to support research
– Advocate for an  of $10 million
annually in federal research into causes
of prematurity
Home Care/Education
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Risk Factors
PTL Prevention/Treatment
PTL Signs/Symptoms
Uterine Contraction Assessment
Fetal Movement Counts
Followup Care
If Home on Bed Rest
• Develop “control center”
– Room near bathroom, phone, TV, electrical
outlets
– Place bed near window if possible, eggcrate
mattress may help
– Cooler for snacks, ice, drinks
– Water pitcher, large mug
– Small shelf/table for books, magazines, etc.
• Separate room for day vs. bedtime
In-Hospital Bed Rest
• Create “home-like” environment
(pictures, favorite pillow, blanket, sweat
suits to wear, etc.)
• Place bed near window
• Change patient rooms if extended stay
• Enc. patient to develop routine (i.e.,
breakfast, Dr. rounds, EFM, shower,
read, rest, lunch, movie/TV, nap, read,
supper, EFM, etc.)
• Get movies, hobbies for patient, etc.
What Nurses Can Do
• Educate on importance of prenatal care,
risk reduction, and recognizing S/S of
PTL
• Screen women for urogenital infections
• Assess women’s stress levels
• Assess for domestic violence
• Assess & help with smoking, alcohol, &
drug use
• Assess nutritional status
References
• Fortney, S. M., Schneider, V. S., & Greenleaf, J. E. (1996).
The physiology of bed rest. In M. J. Fregley & C. M. Blatteis
(Eds.), Handbook of physiology (Vol. 2, pp. 889-939). New
York: Oxford University Press.
• Maloni, J. A. & Park, S. (2005). Postpartum symptoms after
antepartum bedrest. Journal of Obstetric, Gynecologic, &
Neonatal Nursing (34):2, 163-171.
• Thompson, J. F., Roberts, C. L., Currie, M., & Ellwood, D. A.
(2002). Prevalence and persistence of health problems
after childbirth: Associations with parity and method of
birth. Birth, 29, 83-94.
• Maloni, J. (1998). Antepartum Bed Rest: Case Studies,
Research, & Nursing Care. AWHONN