2. PRETERM BIRTH:
Definition of Terms
*with respect to size, a newborn may be appropriate, small or large for
gestational age
Appropriate for gestational age
-newborns whose birth weight is between 10th and the 90th percentile for
gestational age
Small for gestational age
-newborns whose birth weight is usually below the 10th percentile for
gestational age
Large for gestational age
-newborns whose birth weight is usually above the 90th percentile for
gestational age
Low birth weight
-neonates who are born too small weighing 500 to 2500 grams
-Very Low birth weight: 500 to 1500 grams
-Extremely Low birth weight: 500 to 1000 grams
3. PRETERM BIRTH:
Definition of Terms
*with respect to gestational age, the newborn
may be preterm, term or post-term.
Preterm or premature births
-neonates who are born too early before 37
completed weeks
-Late preterm births: delivery at 34 to 36 weeks
of gestation
4. PRETERM BIRTH:
Morbidity
-a variety of morbidities, largely due to system
immaturity, are significantly increased in
infants born before 37 weeks’ gestation
compared with those delivered at term
-these infants also suffer long-term sequelae
such as neurodevelopmental disability
5. PRETERM BIRTH:
Threshold of Viability
-Births before 26 weeks, especially those weighing less
than 750 grams are at the current threshold of
variability
-It is considered appropriate not to initiate resuscitation
for infants younger than 23 weeks or those whose birth
weight is less than 400 grams
-Female gender, singleton pregnancy, corticosteroids
given for lung maturation and higher gestational age
improved the prognosis for infants born at the
threshold of viability
6. PRETERM BIRTH:
Threshold of Viability
-From an obstetrical standpoint, all fetal indications
for cesarean delivery in more advaced
pregnancies are practiced in women at 25 weeks
-Cesarean delivery is not offered for fetal
indications at 23 weeks
-At 24 weeks, cesarean delivery is not offered
unless the fetal weight is estimated at 750 grams
or greater
7. PRETERM BIRTH:
Late Preterm Birth
-Infants between 34 to 36 weeks account
approximately 75% of all preterm births
-Approximately 80% of late preterm births were
due to idiopathic spontaneous preterm labor
or prematurely ruptured membranes while
20% of cases was due to complications such
as hypertension or placental accidents
8. PRETERM BIRTH:
Reasons for Preterm Delivery
There are four main direct reasons for preterm
births in the US:
1. Delivery for maternal or fetal indications in
which labor is induced or the infant is delivered
by pre-labor cesarean delivery – 30-35%
2. Spontaneous unexplained preterm labor with
intact membranes – 40-45%
3. Idiopathic preterm premature rupture of
membranes – 30-35%
4. Twins and higher-order multifetal births
9. PRETERM BIRTH:
Reasons for Preterm Delivery
Maternal indications
-Most common indications for medical intervention resulting in
preterm birth:
1. Preeclampsia
2. Fetal distress
3. Small for gestational age
4. Placental abruption
-Less common causes:
1. Chronic hypertension
2. Placenta previa
3. Unexplained bleeding
4. Diabetes
5. Renal disease
6. Rh isoimmunization
7. Congenital malformations
10. PRETERM BIRTH:
Reasons for Preterm Delivery
Preterm Prematurely Ruptured Membranes (PPROM)
-rupture of membranes before labor and prior to 37 weeks
-Factors implicated:
1. Pathological mechanisms including intra-amniotic
infection
2. Low socioeconomic status
3. Low body mass index (BMI) – less than 19.8
4. Nutritional deficiencies
5. Cigarette smoking
6. Women with prior PPROM
*HOWEVER, most cases of preterm rupture occur without risk
factors or are idiopathic
11. PRETERM BIRTH:
Reasons for Preterm Delivery
Spontaneous Preterm Labor
-Most commonly, preterm birth, up to 45 % of cases – follows
spontaneous labor
-Pathogenesis of Preterm labor are implicated on:
1. Progesterone withdrawal
-as parturition nears, the fetal-adrenal axis becomes
more sensitive to adrenocorticotropic hormone, increasing
the secretion of cortisol stimulation of 17-α-hydroxylase
activity decrease progesterone secretion and increase
estrogen production increased prostaglandin formation
initiates a cascade that culminates in labor
12. PRETERM BIRTH:
Reasons for Preterm Delivery
-Pathogenesis of Preterm labor are implicated on:
2. Oxytocin initiation
-because oxytocin increases the frequency and
intensity of uterine contractions, oxytocin is assumed to
play a role in labor initiation
3. Decidual activation
-seems to be mediated in part by fetal-decidual
paracrine system and through localized decrease in
progesterone concentration
-decidual activation seems to arise in the context of
intrauterine bleeding or occult intrauterine infection
13. PRETERM BIRTH:
Contributing Factors to Preterm Birth
1. Threatened Abortion
-Vaginal bleeding in early pregnancy is
associated with increased adverse outcomes
later
-Both light and heavy bleeding were associated
with subsequent preterm labor, placental
abruption, and subsequent pregnancy loss
prior to 24 weeks
14. PRETERM BIRTH:
Contributing Factors to Preterm Birth
2. Lifestyle Factors
-Cigarette smoking, inadequate maternal weight gain, and
illicit drug use low-birth weight neonates
-Overweight women had lower rates of preterm delivery
before 35 weeks than women with normal weight
-Other maternal factors implicated include young or advanced
maternal age, poverty, short stature, vitamin C deficiency,
and occupational factors such as prolonged walking or
standing, strenuous working conditions, and long weekly
work hours
-Psychological factors such as depression, anxiety, and chronic
stress
-Women injured by physical abuse low birth weight and
preterm birth
15. PRETERM BIRTH:
Contributing Factors to Preterm Birth
3. Racial and Ethnic Disparity
-Women classified as black, African-American,
and Afro-Caribbean are consistently reported
to be at higher risk
4. Work During Pregnancy
-Working long hours and hard physical labor are
probably associated with increased risk
16. PRETERM BIRTH:
Contributing Factors to Preterm Birth
5. Genetic Factors
-Immunoregulatory genes may potentiate
chorioamnionitis in cases of preterm delivery
due to infection
6. Periodontal Disease
-Significantly associated with preterm birth—
odds ratio 2.83 – but data not considered
robust enough
17. PRETERM BIRTH:
Contributing Factors to Preterm Birth
7. Prior Preterm Birth
-A major risk factor for preterm labor is prior
preterm delivery
-The risk of recurrent preterm delivery for
women whose first delivery was preterm was
increased threefold compared with that of
women whose first neonate was born at
term
18. PRETERM BIRTH:
Contributing Factors to Preterm Birth
8. Infection
-It is hypothesized that intrauterine infections trigger
preterm labor by activation of the innate immune
system.
-Microorganisms elicit release of inflammatory cytokines
such as interleukins and tumor necrosis factor (TNF),
stimulate the production of prostaglandin and/or
matrix-degrading enzymes Prostaglandins
stimulate uterine contractions, whereas degradation
of extracellular matrix in the fetal membranes leads
to preterm rupture of membranes.
-Intrauterine infection cause 25-40% of preterm births
19. PRETERM BIRTH:
Contributing Factors to Preterm Birth
8. Infection
-Potential routes of intrauterine infection:
a. Iatrogenic induction
b. Amnionic fluid infection
c. Choriodecidual infection
d. Salpingitis, Villitis or Funisitis
e. From either uterus, placenta, vagina or
even the fetus
20. PRETERM BIRTH:
Contributing Factors to Preterm Birth
8. Infection
-Two microorganisms, Ureaplasma urealyticum and
Mycoplasma hominis, have emerged as important
perinatal pathogens
-Bacterial Vaginosis: condition where normal, hydrogen
peroxide-producing, lactobacillus-predominant vaginal
flora is replaced with anaerobes that include Gardnerella
vaginalis, Mobiluncus species, and Mycoplasma hominis
- associated with spontaneous abortion, preterm labor,
preterm rupture of membranes, chorioamnionitis, and
amnionic fluid infection
- Causes: exposure to chronic stress, ethnic differences,
and frequent or recent douching increased rates of the
condition
21. PRETERM BIRTH:
Diagnosis
Patient Symptoms
Previously, The American Academy of Pediatrics and
the American College of Obstetricians and
Gynecologists (1997) had earlier proposed the
following criteria to document preterm labor:
-Contractions of four in 20 minutes or eight in 60
minutes plus progressive change in the cervix
-Cervical dilatation greater than 1 cm
-Cervical effacement of 80 percent or greater.
*Currently, however, such clinical findings are now
considered inaccurate predictors of preterm delivery
22. PRETERM BIRTH:
Diagnosis
Patient Symptoms
-In addition to painful or painless uterine contractions,
these symptoms are empirically associated with
impending preterm birth:
-pelvic pressure
-menstrual-like cramps
-watery vaginal discharge
-lower back pain
*The signs and symptoms signaling preterm labor,
including uterine contractions may appear only within
24 hours of preterm labor
23. PRETERM BIRTH:
Diagnosis
Cervical Changes
Cervical Dilatation
- Although women with dilatation and effacement in the third
trimester are at increased risk for preterm birth, detection
does not improve pregnancy outcome
- Prenatal cervical examinations are neither beneficial nor
harmful
Cervical Length
- Mean cervical length at 24 weeks was approximately 35
mm
- Women with progressively shorter cervices experienced
increased rates of preterm birth
-Sonographic cervical length, funneling, and prior history of
preterm birth is correlated with delivery before 35 weeks.
24. PRETERM BIRTH:
Diagnosis
Funneling
-bulging of the membranes into the endocervical canal
and protruding at least 25 percent of the entire cervical
length
Incompetent Cervix
Cervical incompetence
-a clinical diagnosis characterized by recurrent,
painless cervical dilatation and spontaneous
midtrimester birth in the absence of spontaneous
membrane rupture, bleeding, or infection
25. PRETERM BIRTH:
Diagnosis
Ambulatory Uterine Monitoring
-An external tocodynamometer belted around
the abdomen and connected to an electronic
waist recorder allows a woman to ambulate
while uterine activity is recorded
-Women who used home monitoring had a
significant increase in the number of
unscheduled visits, and women with twins
had increased use of tocolytic therapy
26. PRETERM BIRTH:
Diagnosis
Fetal Fibronectin
-Present in high concentrations in maternal blood and in
amnionic fluid
-Play a role in intercellular adhesion during implantation and
in the maintenance of placental adhesion to uterine
decidua
-Detected in cervicovaginal secretions in women who have
normal pregnancies with intact membranes at term
-Reflect stromal remodeling of the cervix prior to labor
-Measured using an enzyme-linked immunosorbent assay, and
values exceeding 50 ng/mL are considered positive
*Positive even as early as 8 to 22 weeks, has been
found to be a powerful predictor of subsequent preterm
birth
27. PRETERM BIRTH:
Prevention
Progesterone Use
-American College of Obstetricians and Gynecologists: progesterone
therapy should be limited to women with a documented history of a
previous spontaneous birth at less than 37 weeks
Cervical Cerclage
-Three circumstances when cerclage placement may be used to prevent
preterm birth:
1. History of recurrent midtrimester losses and who are diagnosed with
an incompetent cervix
2. Short cervix on sonographic examination
3.“Rescue" cerclage, done emergently when cervical incompetence is
recognized in the women with threatened preterm labor
28. PRETERM BIRTH:
Management of Preterm Rupture of
Membranes and Preterm Labor
American College of Obstetricians and
Gynecologists: Despite the numerous
management methods proposed, the incidence of
preterm birth has changed little over the past 40
years. Uncertainty persists about the best
strategies for managing preterm labor
29. PRETERM BIRTH:
Management of Preterm Rupture of
Membranes and Preterm Labor
Diagnosis of Preterm Prematurely Ruptured Membranes
-A history of vaginal leakage of fluid, either as a continuous
stream or as a gush should prompt a speculum
examination to visualize gross vaginal pooling of amnionic
fluid, clear fluid from cervical canal, or both.
-Confirmation of ruptured membranes is usually
accompanied by sonographic examination to:
-Assess amnionic fluid volume
-Identify the presenting part
-Estimate gestational age
30. PRETERM BIRTH:
Management of Preterm Rupture of
Membranes and Preterm Labor
Diagnosis of Preterm Prematurely Ruptured
Membranes
*basis for frequently used pH testing for ruptured
membranes
*blood, semen, antiseptics or bacterial vaginosis are
also alkalinic and can give false-positive result
pH
AMNIONIC FLUID 7.1-7.3 (slightly alkalinic)
VAGINAL SECRETIONS 4.5-6.0 (acidic)
31. PRETERM BIRTH:
Management of Preterm Rupture of
Membranes and Preterm Labor
Natural History of Preterm Ruptured Membranes
-The time from preterm ruptured membranes to
delivery is inversely proportional to the
gestational age when rupture occurs
32. PRETERM BIRTH:
Management of Preterm Rupture of
Membranes and Preterm Labor
Expectant Management
-Tocolysis or expectant management did not improve
perinatal outcomes
-Other considerations with expectant management involve
the use of digital cervical examination and cerclage
-Risks of Expectant Management:
-No improved neonatal outcomes with expectant
management beyond 33 weeks
-The volume of amnionic fluid remaining after rupture
appears to have prognostic importance in pregnancies
before 26 weeks
33. PRETERM BIRTH:
Management of Preterm Rupture of
Membranes and Preterm Labor
-Risks of Expectant Management:
-Oligohydramnios - defined by the absence of fluid
pockets 2 cm or larger
*all women with oligohydramnios delivered before
25 weeks, whereas 85 percent with adequate
amnionic fluid volume were delivered in the third
trimester
- Lung hypoplasia has a threshold of development of 23
weeks or less
- Limb compression deformities
- Umbilical cord prolapse – increased rate in women with
preterm ruptured membranes and noncephalic
presentation, especially before 26 weeks
34. PRETERM BIRTH:
Management of Preterm Rupture of
Membranes and Preterm Labor
Clinical Chorioamnionitis:
- prolonged membrane rupture is associated with
increased fetal and maternal sepsis
- If diagnosed, prompt efforts to effect delivery, preferably
vaginally, are initiated
- Fever is the only reliable indicator for this diagnosis
-Temperature of 38°C or higher accompanying ruptured
membranes implies infection
-During expectant management, monitoring for sustained
maternal or fetal tachycardia, for uterine tenderness, and
for a malodorous vaginal discharge is warranted
35. PRETERM BIRTH:
Management of Preterm Rupture of
Membranes and Preterm Labor
Clinical Chorioamnionitis:
- Associated with higher incidence of:
- sepsis
-respiratory distress syndrome
-early-onset seizures
-intraventricular hemorrhage
-periventricular leukomalacia
-vulnerable to neurological injury
36. PRETERM BIRTH:
Management of Preterm Rupture of
Membranes and Preterm Labor
Antimicrobial Therapy
- Only three of 10 outcomes were possibly benefited:
1. Fewer women developed chorioamnionitis 2.
Fewer newborns developed sepsis
3. Pregnancy was more often prolonged 7 days in
women given antimicrobials
*Neonatal survival was unaffected, as was the incidence of
necrotizing enterocolitis, respiratory distress, or
intracranial hemorrhage
-Amoxicillin-clavulanate regimen was not recommended
with an increased incidence of necrotizing enterocolitis
37. PRETERM BIRTH:
Management of Preterm Rupture of
Membranes and Preterm Labor
Corticosteroids
- The National Institutes of Health Consensus
Development Conference (2000) recommended a single
course of antenatal corticosteroids for women with
preterm membrane rupture before 32 weeks and in
whom there was no evidence of chorioamnionitis
- American College of Obstetricians and Gynecologists:
-Single-dose therapy from 24-32 weeks
-No consensus regarding treatment between 32 and
34 weeks.
-Not recommended prior to 24 weeks
38. PRETERM BIRTH:
Management of Preterm Rupture of
Membranes and Preterm Labor
Membrane Repair
-Tissue sealants have been used for a variety of
purposes in medicine and have become
important in maintaining surgical hemostasis and
stimulating wound healing
39. PRETERM BIRTH:
Management of Preterm Rupture of
Membranes and Preterm Labor
Recommended Management
Gestational Age Management by the American College of Obstetricians and Gynecologists
34 weeks or more -Proceed to delivery, usually by induction of labor
-Group B streptococcal prophylaxis is recommended
32 weeks to 33
completed weeks
-Expectant management unless fetal pulmonary maturity is documented
-Group B streptococcal prophylaxis is recommended
-Corticosteroids—no consensus, but some experts recommend
-Antimicrobials to prolong latency if no contraindications
24 weeks to 31
completed weeks
-Expectant management
-Group B streptococcal prophylaxis is recommended
-Single-course corticosteroids use is recommended
-Tocolytics—no consensus
-Antimicrobials to prolong latency if no contraindications
Before 24 weeks -Patient counseling
-Expectant management or induction of labor
-Group B streptococcal prophylaxis is not recommended
-Corticosteroids are not recommended
-Antimicrobials—there are incomplete data on use in prolonging latency
40. PRETERM BIRTH:
Preterm Labor with Intact Membranes
-Women with signs and symptoms of preterm labor
with intact membranes are managed much the
same as those with preterm ruptured
membranes
-The cornerstone of treatment is to avoid delivery
prior to 34 weeks, if possible
41. PRETERM BIRTH:
Preterm Labor with Intact Membranes
Amniocentesis to Detect Infection
-The American College of Obstetricians and
Gynecologists (2003) has concluded that there is
no evidence to support routine amniocentesis to
identify infection.
42. PRETERM BIRTH:
Preterm Labor with Intact Membranes
Corticosteroid Therapy to Enhance Fetal Lung Maturation
- Corticosteroid therapy was effective in lowering the incidence of
respiratory distress and neonatal mortality rates if birth was delayed for
at least 24 hours after initiation of betamethasone
- Lower dose had less severe effects on somatic growth without affecting
cell proliferation in the fetal brain
- American College of Obstetricians and Gynecologists: single-course
therapy for Corticosteroids
- Rescue Therapy: refers to administration of a repeated corticosteroid
dose when delivery becomes imminent and more than 7 days have
elapsed since the initial dose
*should not be routinely used and reserved for clinical trials
-DEXAMETHASON vs BETAMETHASONE: These two drugs were
comparable in reducing the rates of major neonatal morbidities in
preterm infants
43. PRETERM BIRTH:
Preterm Labor with Intact Membranes
Antimicrobials
- Antimicrobial treatment of women with preterm
labor for the sole purpose of preventing delivery
is generally not recommended
- Fetal exposure to antimicrobials in this clinical
setting was associated with an increased cerebral
palsy rate at age 7 years compared with that of
non-exposed infants
44. PRETERM BIRTH:
Preterm Labor with Intact Membranes
Emergency or Rescue Cerclage
- If cervical incompetence is recognized with threatened
preterm labor, emergency cerclage can be attempted,
albeit with an appreciable risk of infection and pregnancy
loss
- Delivery delay was significantly greater in the cerclage
group compared with that of bed rest alone—54 versus 24
days
- Nulliparity, membranes extending beyond the external
cervical os, and cerclage prior to 22 weeks were associated
with a significantly decreased chance of pregnancy
continuation to 28 weeks or beyond
45. PRETERM BIRTH:
Preterm Labor with Intact Membranes
Inhibition of Preterm Labor
- The American College of Obstetricians and
Gynecologists: Tocolytic agents do not markedly
prolong gestation, but may delay delivery in
some women for at least 48 hours.
*May facilitate transport to a regional obstetrical
center and allow time for administration of
corticosteroid therapy
46. PRETERM BIRTH:
Preterm Labor with Intact Membranes
Bed Rest
- One of the most often prescribed interventions
during pregnancy, yet one of the least studied
- Bed rest in the hospital compared with bed rest at
home had no effect on pregnancy duration in
women with threatened preterm labor before 34
weeks
- Bed rest for 3 days or more increased
thromboembolic complications
- Significant bone loss in pregnant women prescribed
outpatient bed rest
47. PRETERM BIRTH:
Preterm Labor with Intact Membranes
β-Adrenergic Receptor Agonists
- A number of compounds react with β-adrenergic
receptors to reduce intracellular ionized calcium
levels and prevent activation of myometrial
contractile proteins
- Ritodrine and terbutaline have been used in
obstetrics
*only Ritodrine had been approved for preterm
labor by the Food and Drug Administration
48. PRETERM BIRTH:
Preterm Labor with Intact Membranes
β-Adrenergic Receptor Agonists
-Ritodrine:
-neonates whose mothers were treated with ritodrine for threatened
preterm labor had lower rates of death and respiratory distress
-may lead to Pulmonary edema
-withdrawn by manufacturer in 2003
- Terbutaline
- commonly used to forestall preterm labor
- can cause pulmonary edema
- terbutaline pumps cause sudden maternal death and a newborn with
myocardial necrosis after the mother used the pump for 12 weeks
- oral terbutaline therapy to prevent preterm delivery has also not been
effective
49. PRETERM BIRTH:
Preterm Labor with Intact Membranes
Magnesium Sulfate
- Its role is presumably that of a calcium antagonist
- Intravenously administered magnesium sulfate—a 4-
gram loading dose followed by a continuous infusion
of 2 grams/hour—usually arrests labor
- Monitored closely for evidence of hypermagnesemia
- Parkland Hospital: "Time to Quit" on the use of
magnesium sulfate for tocolysis on the basis that
this therapy was ineffective and potentially harmful
to infants
50. PRETERM BIRTH:
Preterm Labor with Intact Membranes
Magnesium Sulfate
- Neonatal effects:
- reduced incidence of cerebral palsy at 3 years
- minimize the inflammatory effects of infection
- Neuroprotection magnesium from 23 to 32
completed weeks
*A 6-gram loading dose is followed by an infusion of
2 gram per hour for at least 12 hours
51. PRETERM BIRTH:
Preterm Labor with Intact Membranes
Prostaglandin Inhibitors
- Drugs that inhibit prostaglandins have been of
considerable interest because prostaglandins are
intimately involved in contractions of normal labor
- Prostaglandin antagonists act by:
-inhibiting prostaglandin synthesis
-blocking prostaglandin action on target organs
*A group of enzymes collectively termed prostaglandin
synthase is responsible for the conversion of free
arachidonic acid to prostaglandins
-acetylsalicylate and indomethacin block this
system
52. PRETERM BIRTH:
Preterm Labor with Intact Membranes
Prostaglandin Inhibitors
-Indomethacin:
-administered orally or rectally
-50 to 100 mg dose is followed at 8-hour intervals
not to exceed a total 24-hour dose of 200 mg
-Serum concentrations usually peak 1 to 2 hours
after oral administration,whereas levels after rectal
administration peak slightly sooner.
-Limited usese to 24 to 48 hours because of
concerns of oligohydramnios but is reversible with
discontinuation of indomethacin.
53. PRETERM BIRTH:
Preterm Labor with Intact Membranes
Calcium Channel Blockers
-Myometrial activity is directly related to cytoplasmic free
calcium, and a reduction in its concentration inhibits
contractions
-Act to inhibit, by a variety of mechanisms, the entry of
calcium through channels in the cell membrane
-Although nifedipine treatment reduced births of neonates
weighing less than 2500 g, significantly more of these
were admitted for intensive care
-Combination of nifedipine with magnesium for tocolysis is
potentially dangerous since nifedipine enhances
neuromuscular blocking effects of magnesium that can
interfere with pulmonary and cardiac function
54. PRETERM BIRTH:
Preterm Labor with Intact Membranes
Atosiban
-Nonapeptide oxytocin analog is a competitive antagonist of
oxytocin-induced contractions
-Failed to improve relevant neonatal outcomes and was
linked with significant neonatal morbidity
Nitric Oxide Donors
-potent smooth-muscle relaxants affect the vasculature, gut,
and uterus
-Nitroglycerin administered orally, transdermally, or
intravenously was not effective or showed no superiority
to other tocolytics
-Maternal hypotension was a common side effect
55. PRETERM BIRTH:
Preterm Labor with Intact Membranes
Summary of Tocolytic Use for Preterm Labor
-Tocolytics stop contractions temporarily but rarely
prevent preterm birth
-Although delivery may be delayed long enough for
administration of corticosteroids, treatment does
not result in improved perinatal outcome
-Tocolytic therapy can prolong gestation, but that β-
agonists are not better than other drugs and pose
potential maternal danger.
-There are no benefits of maintenance tocolytic
therapy
56. PRETERM BIRTH:
Preterm Labor with Intact Membranes
Summary of Tocolytic Use for Preterm Labor
-As a general rule, if tocolytics are given, they should
be given concomitantly with corticosteroids.
-The gestational age range for their use is debatable,
but because corticosteroids are not generally used
after 33 weeks and because the perinatal outcomes
in preterm neonates are generally good after this
time, most practitioners do not recommend use of
tocolytics at or after 33 weeks
57. PRETERM BIRTH:
Recommended Management of
Preterm Labor
The following considerations should be given to women in preterm labor:
1. Confirmation of preterm labor
2.For pregnancies less than 34 weeks in women with no maternal or fetal
indications for delivery, close observation with monitoring of uterine
contractions and fetal heart rate is appropriate. Serial examinations
are done to assess cervical changes
3. For pregnancies less than 34 weeks, corticosteroids are given for
enhancement of fetal lung maturation
4. Consideration is given for maternal magnesium sulfate infusion for 12
to 24 hours to afford fetal neuroprotection
58. PRETERM BIRTH:
Recommended Management of
Preterm Labor
The following considerations should be given to women in preterm labor:
5. For pregnancies less than 34 weeks in women who are not in advanced
labor, some practitioners believe it is reasonable to attempt inhibition
of contractions to delay delivery while the women are given
corticosteroid therapy and group B streptococcal prophylaxis.
*Although tocolytic drugs are not used at Parkland Hospital, they are
given at University of Alabama at Birmingham Hospital
6. For pregnancies at 34 weeks or beyond, women with preterm labor are
monitored for labor progression and fetal well-being
7. For active labor, an antimicrobial is given for prevention of neonatal
group B streptococcal infection
59. PRETERM BIRTH:
Intrapartum Management
-In general, the more immature the fetus, the greater the risks of
labor and delivery
-Labor:
-Whether labor is induced or spontaneous, abnormalities of
fetal heart rate and uterine contractions should be sought
-Continuous electronic monitoring
-Fetal tachycardia, especially with ruptured membranes, is
suggestive of sepsis
-Intrapartum acidemia (umbilical artery blood pH less than
7.0) may intensify some of the neonatal complications usually
attributed to preterm delivery—more severe respiratory
disease in preterm neonates
-Group B streptococcal infections are common and dangerous
in the preterm neonate - prophylaxis should be provided
60. PRETERM BIRTH:
Intrapartum Management
-Delivery:
-In the absence of a relaxed vaginal outlet, an
episiotomy for delivery may be necessary once the
fetal head reaches the perineum
-Perinatal outcome data do not support routine
forceps delivery to protect the "fragile preterm fetal
head"
-Staff proficient in resuscitative techniques
commensurate with the gestational age and fully
oriented to any specific problems should be present
at delivery
61. PRETERM BIRTH:
Intrapartum Management
-Prevention of Neonatal Intracranial Hemorrhage:
-Cesarean delivery did not lower the risk of
mortality or intracranial hemorrhage
-Avoidance of active-phase labor is impossible in
most preterm births because the route of
delivery cannot be decided until the active phase
of labor is firmly established