ob gyne

1. PRETERM AND POSTTERM
25th edition Williams
Far Eastern University
Dr. Nicanor Reyes Medical Foundation
Department of Obstetrics and Gynecology

2. PRETERM BIRTH
Far Eastern University
Dr. Nicanor Reyes Medical Foundation
Department of Obstetrics and Gynecology

3. DEFINITION OF TERMS
• Low Birthweight - neonates who are born too
small
• Preterm or premature birth - neonates born
too early
• Low birthweight - 1500-2500 grams
• Very low birthweight - 500-1500 grams
• Extremely low birthweight - 500-1000grams

4. DEFINITION OF TERMS
I. AS TO SIZE
Small-for-gestational age / fetal growth restriction / intrauterine growth
restriction (SGA/IUGR)
• birthweight below the 10th percentile for gestational age
Large-for-gestational age (LGA)
• birthweight above the 90th percentile
Appropriate-for-gestational age (AGA)
• newborns with weight between the 10th and 90th percentiles
II. AS TO AOG
Preterm or premature birth
• neonates born too early
• delivery before 37 completed weeks
Term
• 37 – 42 weeks
Post term
• > 42 weeks

5. CAUSES OF PRETERM BIRTH
 SPONTANEOUS PRETERM LABOR
PRETERM PREMATURE RUPTURE OF
MEMBRANES
MULTIFETAL PREGNANCY

6. CONTRIBUTING FACTORS
o Pregnancy factors
o Lifestyle factors
o Genetic factors
o Periodontal disease
o Interval between pregnancies
o Prior preterm birth
o Infection

7. SPONTANEOUS PRETERM LABOR
Four major causes:
1. UTERINE DISTENSION
2. MATERNAL-FETAL STRESS
3. PREMATURE CERVICAL CHANGES
4. INFECTION

8. Causes of spontaneous preterm labor . . .
UTERINE DISTENSION
• EXAMPLE: MULTIPLE PREGNANCY,
HYDRAMNIOS
• Leads to premature loss of uterine quiescence
due to the release of:
– Contractions associated protein(CAP)
– Gastrin releasing peptides (GRP)
– Stretch induced potassium channel - TREK -1
– Maternal release of corticotrophin releasing
hormone and estrogen can further enhance the
expression of myometrial CAP genes

9. Causes of spontaneous preterm labor …
MATERNAL AND FETAL STRESS
• STRESSIncrease CRH in the placentaworks
with ACTH to increase maternal and fetal
steroid productionincrease fetal DHEAS
estriol
• Increase cortisol and estrogen loss of
uterine quiescence

10. Causes of spontaneous preterm labor …
CERVICAL DYSFUNCTION
• Premature cervical remodeling precedes
premature labor onset
• Cervical dysfunction of either the epithelia or
stromal extracellular matrix is the underlying
cause.
• Mechanical competence of cervix can be
reduced e.g. genetic mutations in components
of collagen and elastic fibers or proteins
required for their assembly  risk factors for
cervical insufficiency, PPROM, preterm birth

11. Causes of spontaneous preterm labor. . .
INFECTION

12. SOURCES OF INTRAUTERINE
INFECTION
1. transplacental transfer of maternal systemic
infection
2. retrograde flow of infection into the
peritoneal cavity via the fallopian tubes
3. ascending infection with bacteria from the
vagina and cervix – most common entry route

13. PRETERM PREMATURE RUPTURE
OF MEMBRANES
• DEFINITION: spontaneous rupture of
membranes before 37 completed weeks and
before labor onset
• MAJOR PREDISPOSING EVENTS:
• Intrauterine infection
• Oxidative stress-induced DNA damage
• Premature cellular senescence

14. PPROM
• Associated risk factors:
– Lower socio-economic status
– Body mass index <19.8
– Nutritional deficiencies
– Cigarette smoking

15. I. Pregnancy Factors
• Vaginal bleeding or spotting is associated
with increased incidence of subsequent
pregnancy loss prior to 24 weeks,
preterm labor, and placental abruption
CONTRIBUTING FACTORS TO
PRETERM BIRTH

16. II. Lifestyle Factors
1. Cigarette smoking
2. Inadequate maternal weight gain
3. Illicit drug use
4. Extremes of maternal weight – underweight and obese
5. Young or advanced maternal age
6. Poverty
7. Short stature
8. Vitamin C deficiency
9. Psychological factors- anxiety, depression, chronic
stress
10. Working long hours and hard physical labor
PRETERM BIRTH

17. III. Genetic Factors
• Recurrent, familial and racial nature of
preterm birth
• Implication of immunoregulatory genes in
potentiating chorioamnionitis
• Birth defects was associated with preterm
birth
PRETERM BIRTH

18. PRETERM BIRTH
• IV. Periodontal Disease
– gum inflammation due to anaerobic
microorganism
– associated with preterm birth
– treatment during pregnancy is safe

19. PRETERM BIRTH
• V. Interval between births
• intervals of less than 18 months and more
than 59 months were associated with greater
risks for both preterm birth and small for
gestation newborns

20. PRETERM BIRTH
• VI. Prior preterm birth
– Most important risk factor
– If first delivery was preterm- three fold increase
than a patient with a term first delivery
– Risk of recurrent preterm birh is influenced by
three factors:
• Frequency of prior preterm deliveries
• Severity as measured by gestational age
• Order in which the prior preterm delivery occurred.

21. VII. Infection
Antibiotic prophylaxis - did not reduce rate of
preterm birth or that of histological
chorioamnionitis; not recommended to
prevent preterm birth in women with preterm
labor and intact membranes.
PRETERM BIRTH

22. Bacterial vaginosis
Normal, hydrogen peroxide-producing
lactobacillus-predominant vaginal flora is replaced
with anaerobes.
Gram staining– Nugent score
Assessed clinically with Amsel criteria
Associated with spontaneous abortion, preterm
labor, PPROM, chorioamnionitis and amniotic fluid
embolism.
Risk factors: chronic stress, ethnic differences ,
frequent or recent douching

23. INFECTIONS RELATED TO PRETERM LABOR
INFECTION ETIOLOGY DIAGNOSTIC
FEATURES
MANAGEMENT
Bacterial
vaginosis
Gardnerella
vaginalis,
Mobiluncus
species, and
Mycoplasma
hominis
-Vaginal pH > 4.5
-Homogenous
vaginal discharge
- Amine odor when
vaginal secretions
are mixed with KOH
- Vaginal epithelial
cells heavily coated
with bacilli “clue
cells”
- Gram staining of
vaginal secretions
show few white cells
along with mixed
flora as compared
with the normal
predominance of
lactobacilli
Metronidazole 500
mg BID for 7 days

24. Periodontitis Fusobacterium
nucleatum and
Capnocytophaga
species
Teeth cleaning
and polishing;
deep root
scaling and
planning plus
metronidazole
INFECTIONS RELATED TO PRETERM LABOR

25. DIAGNOSIS OF PRETERM LABOR
1. SYMPTOMS
preterm labor-regular contractions before 37
weeks associated with cervical change
 contractions with pelvic pressure, menstrual
like cramps, watery vaginal discharge, lower
back pain – empirically associated with
impending preterm birth.

26. DIAGNOSIS
II. Cervical Change
- Asymptomatic cervical dilatation after midpregnancy
suspected to be a risk factor for preterm delivery,
although some consider it a normal anatomical
variant.
- Prenatal cervical examinations in asymptomatic
women are neither beneficial nor harmful.

27. III. Ambulatory Uterine Monitoring
• an external tocodynamometer is belted
around the abdomen and connected to an
electronic waist recorder – allows a woman to
ambulate while uterine activity is recorded
• ACOG does not recommend this expensive,
bulky, and time-consuming system which does
not reduce the rate of preterm birth
DIAGNOSIS OF PRETERM LABOR

28. IV. Fetal Fibronectin (fFN)
- Glycoprotein produced by hepatocytes, fibroblasts,
endothelial cells, and fetal amnion cells
- High concentrations in maternal blood and amnionic
fluid
- Function in intercellular adhesion during
implantation and in maintenance of placental
adherence to uterine decidua
- Detected in cervico-vaginal secretions in normal
pregnancies with intact membranes at term
DIAGNOSIS

29. Fetal Fibronectin (fFN). . .
• detection in cervico-vaginal secretions before
membrane rupture was a possible marker for
preterm labor
• values exceeding 50 ng/mL are considered
positive
• positive value as early as 18 to 22 weeks -
powerful predictor of subsequent preterm birth
DIAGNOSIS

30. V. Cervical Length Measurement
- Progressively shorter cervical canals assessed
sonographically are associated with increased
rates of preterm birth
- Performed after 16 weeks gestation
Diagnosis of Preterm Labor

31. • Cervical Length Measurement …
• value of cervical length to predict preterm
birth is only for high risk women
• routine cervical ultrasonography - no role in
the screening of normal-risk pregnant women
Diagnosis of Preterm Labor

32. Ultrasonographic Measurement of
Cervical Length
• mean cervical length at 24 weeks was about 35
mm, and those women with progressively shorter
cervices experienced increased rates of preterm
birth
• women with a previous preterm birth (< 32
weeks) should undergo, on her next pregnancy,
an ultrasound examination of cervical length
between 16 to 24 weeks AOG; a shortened cervix
( < 25mm ) correlates with another subsequent
preterm birth before 35 weeks

33. PRETERM BIRTH PREVENTION
I. Cervical Cerclage – may be used in the following:
I. With a history of recurrent mid-trimester losses
and diagnosed with cervical insufficiency
II. With a sonographic examination of a short cervix
III. “rescue cerclage” – done emergently when
cervical incompetence is recognized in women
with threatened preterm labor

34. Cervical cerclage:
- Sonographically short cervix only, no history of
preterm – no advantage
- ACOG: consider cerclage if
- Singleton pregnancy
- Prior spontaneous preterm birth before 34 weeks
- Cervical length <25 mm
- Gestational age <24 weeks

35. MANAGEMENT OF PRETERM PREMATURE
RUPTURE OF MEMBRANES(PPROM)
DIAGNOSIS:
• A history of vaginal leakage of fluid
• Sterile speculum examination - gross vaginal
pooling of amnionic fluid, clear fluid from the
cervical canal, or both
• Confirmation :ultrasound to assess amnionic fluid
volume; to identify the presenting part; and if not
previously determined, to estimate gestational
age
• PH testing- alkaline(7.1-7.2)
• False positive result: semen, blood, antiseptic,
bacterial vaginosis

36. RECOMMENDED MANAGEMENT
OF PPROM
• 34 WEEKS OR MORE
• Plan delivery: labor induction (unless
contraindicated )
• Grp B streptococcus prophylaxis
• Single corticosteroid course may be
considered up to 36 6/7 weeks

37. RECOMMENDED MANAGEMENT
OF PPROM
• 32 weeks to 33 COMPLETED WEEKS
• Expectant management
• Grp B streptococcal prophylaxis
• Single Corticosteroid course
• antimicrobials to prolong latency

38. RECOMMENDED MANAGEMENT
OF PPROM
• 24 weeks to 31 completed weeks
• Expectant management
• Grp B Streptococcal prophylaxis
• Single Corticosteroid course
• antimicrobials to prolong latency
• Tocolytics -no consensus
• Magnesium sulfate for neuroprotection may
be considered

39. RECOMMENDED MANAGEMENT
OF PPROM
• Before 24 WEEKS
• Expectant management or induction of labor
• Grp B streptococcal prophylaxis – not
recommended
• Single corticosteroid course and antimicrobials
may be considered
• Tocolytics - no consensus

40. 1.AMNIOCENTESIS TO DETECT INFECTION:
- not routinely recommended
2.CORTICOSTEROIDS FOR LUNG MATURATION
Betamethasone 12 mg every24 hrs x 2 doses OR
Dexamethasone 6 mg every 12 hrs for 4 doses
Rescue dose: single course of corticosteroid
given to women whose prior course was
administered at least 7 days previously and
who are <34 weeks gestation
MANAGEMENT OF PRETERM LABOR
WITH INTACT MEMBRANES

41. MANAGEMENT OF PRETERM LABOR WITH
INTACT MEMBRANES
3. Magnesium sulfate for neuroprotection
• Prevent cerebral palsy in neonates
• NICHD MFMU-(2008)-MgSO4 was given at 24-
31 weeks to women at risk of imminent
preterm delivery; 6 grams bolus over 2—30
min followed by infusion of 2 grams per hour
for at least 12 hrs
• threatened preterm delivery from 24th to 27
6/7 weeks (PARKLAND Hosp)

42. 4. ANTIMICROBIALS
not recommended if will be used solely to prevent preterm
labor
5. BED REST
Although frequently prescribed, bed rest is only rarely
indicated
6. CERVICAL PESSARIES(ARABIN PESSARY)
currently recommend prophylaxis only within research
protocols
7. EMERGENCY OR RESCUE CERCLAGE
MANAGEMENT OF PRETERM LABOR WITH
INTACT MEMBRANES

43. MANAGEMENT OF PRETERM LABOR WITH
INTACT MEMBRANES
8. TOCOLYSIS to treat preterm labor
• Tocolytic agents do not markedly prolong
gestation but may delay delivery in some
women for up to 48 hours
• May allow transport to an obstetrical center
with higher level neonatal care
• Permit time for a course of corticosteroid
therapy

44. MANAGEMENT OF PRETERM LABOR WITH
INTACT MEMBRANES
TOCOLYSIS . . .
1. Beta adrenergic receptor agonists - reduce
intracellular ionized calcium levels and prevent
activation of myometrial contractile proteins
– e.g. Ritodrine, Terbutaline,
Side effects: pulmonary edema, volume overload,
arrhythmia and myocardial ischemia

45. TOCOLYSIS . . .
2. Magnesium sulfate
• In a sufficiently high concentration can alter
myometrial contractility
• calcium antagonist - may inhibit labor
• DOSE: 4-g IV loading dose followed by a continuous
infusion of 2 g/hr
• Ineffective and potentially harmful (prolonged use-
fetal bone thinning and fractures)
MANAGEMENT OF PRETERM LABOR WITH
INTACT MEMBRANES

46. MANAGEMENT OF PRETERM LABOR WITH
INTACT MEMBRANES
TOCOLYSIS . . .
3. Prostaglandin inhibitors (ex. Indomethacin)
Mode of action: inhibits prostaglandin synthesis
or by blocking their action on target organs
Side effects: patent ductus arteriosus,
oligohydramnios, necrotizing enterocolitis,
intaventricular hemorrhage

47. MANAGEMENT OF PRETERM LABOR WITH
INTACT MEMBRANES
TOCOLYSIS . . .
4. CALCIUM CHANNEL BLOCKERS
• Act to inhibit calcium entry through cell
membrane channels thus decreasing uterine
contractility
• Example: Nifedipine

48. MANAGEMENT OF PRETERM LABOR WITH
INTACT MEMBRANES
TOCOLYSIS . . .
5. ATOSIBAN
• Nona-peptide oxytocin analogue is an
oxytocin receptor antagonist (ORA)
6. NITRIC OXIDE DONORS
• Example: nitroglycerine
• Not effective and causes maternal
hypotension

49. INTRAPARTUM MANAGEMENT
1. Labor
• Continuous electronic monitoring
• Fetal tachycardia, especially with ruptured
membranes, is suggestive of sepsis
2. Prevention of neonatal group B Streptococcal
infections
• The American College of Obstetricians and
Gynecologists, recommend either penicillin G or
ampicillin intravenously every 4 - 6 hours until
delivery for women in preterm labor

50. 3. Delivery
• Staff proficient in resuscitative techniques and
fully oriented to any specific problems should be
present
4. Prevention of neonatal intracranial hemorrhage
• Preterm newborns have germinal matrix bleeding
that can extend to more serious intra-ventricular
hemorrhage
• Cesarean delivery to obviate trauma from labor
and vaginal delivery to prevent these
complications has not been validated
Intrapartum Management

51. POSTTERM PREGNANCY
25th Edition Williams
Far Eastern University
Dr. Nicanor Reyes Medical Foundation
Department of Obstetrics and Gynecology

52. DEFINITION OF TERMS
• Postmature – newborn with recognizable clinical
features indicating a pathologically prolonged
pregnancy.
• Postdates - should be abandoned, because the real
issue in many postterm pregnancies is "post-what
dates?"
• Postterm or Prolonged Pregnancy - preferred
expression for an extended pregnancy
• According to ACOG(2016) : 42 completed weeks (294
days) or more from the first day of the last menstrual
period.

53. Postmaturity Syndrome
Characteristic appearance / Features:
• wrinkled, patchy, peeling skin; a long, thin
body suggesting wasting; and advanced
maturity because the infant is open-eyed,
unusually alert, and appears old and worried-
looking
• Skin wrinkling prominent on the palms and
soles
• Nails are long

54. ADVERSE MATERNAL AND PERINATAL OUTCOMES
ASSOCIATED WITH POSTTERM PREGNANCY
MATERNAL
• Fetal macrosomia
• Oligohydramnios
• Preeclampsia
• Cesarean delivery – dystocia , fetal jeopardy
• Shoulder dystocia
• Postpartum hemorrhage
• Perineal lacerations

55. ADVERSE MATERNAL AND PERINATAL OUTCOMES
ASSOCIATED WITH POSTTERM PREGNANCY
PERINATAL
• Stillbirth
• Post-maturity syndrome
• NICU admission
• Meconium aspiration
• Neonatal convulsions
• Hypoxic-ischemic encephalopathy
• Birth injuries
• Childhood obesity

56. PATHOPHYSIOLOGY
• Postmaturity Syndrome
• Wrinkled patchy peeling skin,
• long thin body,wasting,
• open eyed,alert,
• appears old and worried
• Long nails

57. PATHOPHYSIOLOGY
• Placental dysfunction
– The concept that post-maturity stems from
placental insufficiency has persisted despite an
absence of morphological or significant
quantitative findings of placental degeneration

58. PATHOPHYSIOLOGY
• Fetal Distress and Oligohydramnios
• consequence of cord compression associated with
oligohydramnios
• one or more prolonged decelerations  emergency
cesarean deliveries for fetal jeopardy
• findings are consistent with cord occlusion as the
proximate cause of the non-reassuring tracings
• Other correlates included oligohydramnios and
viscous meconium  meconium aspiration
syndrome

59. Prolonged fetal heart rate deceleration prior to emergency cesarean
delivery in a postterm pregnancy with oligohydramnios.

60. PATHOPHYSIOLOGY
• Fetal – Growth Restriction
• stillbirths were more common among growth-
restricted infants who were delivered at 42 weeks or
beyond
• one third of the postterm stillbirths were growth
restricted
• morbidity and mortality were significantly increased
in the growth-restricted infants

61. COMPLICATIONS
1. Oligohydramnios - amniotic fluid index of
less than 5 cms
2. Macrosomia – Although growth velocity
slows at 37 weeks, most fetuses continue to
gain weight.
3. Medical And Obstetric Complications
– Pregnancy should not be allowed to continue past
42 weeks
– Ex: hypertension, diabetes, prior CS

62. ANTEPARTUM MANAGEMENT
• Induction Factors
– “unfavorable cervix” – “undilated cervix” ; Bishop
score <7  2-fold higher CS rate for “dystocia”
– PGE2 and PGE1
– cervical length of 3 cm or less determined by
transvaginal ultrasonography was predictive of
successful induction.

63. • Induction factors …
• The American College of Obstetricians and
Gynecologists (1997) has concluded that prostaglandin
gel can be used safely in postterm pregnancies
Sweeping or stripping of the membranes:
• decreased the frequency of postterm pregnancy.
• stripping did not modify the risk for cesarean delivery
and maternal and neonatal infections were not
increased
Station of the vertex is important in predicting successful
postterm pregnancy induction.
ANTEPARTUM MANAGEMENT

64. ANTEPARTUM MANAGEMENT
• Management Strategies:
• Antepartum interventions are indicated in cases of
postterm pregnancies
• When to induce? 41 or 42 weeks?
• 41 weeks with favorable cervix, induce labor
• 41 weeks with unfavorable cervix, antepartum fetal
testing
• 42 weeks, whether the cervix is favorable or not,
labor is generally induced

65. ANTEPARTUM MANAGEMENT
Management Strategies:
41 0/7 weeks , uncomplicated  consider fetal
surveillance, membrane sweeping, labor induction
41 0/7 weeks, complicated (hypertension,
oligohydramnios, decreased fetal movement)  labor
induction
42 0/7 – 42 6/7 weeks  labor induction

66. INTRAPARTUM MANAGEMENT
• Contraction stress test - done prior to induction
– If negative- Start Induction
– If positive - CS
• Close monitoring of labor with continuous CTG –
(fetal heart rate and uterine contractions)
• Amniotomy – Identification of thick meconium;
aspiration may cause severe fetal pulmonary
dysfunction and neonatal death
• Thick meconium stained AF remote from delivery –
Cesarean delivery, especially when CPD suspected or
uterine dysfunction evident.