Rex M. Poblete, M.D.,FPOGS

PRETERM LABOR

POST-TERM PREGNANCY

PROM(Premature Rupture of Membranes)

IUFD (Intrauterine Fetal Demise)

PRETERM LABOR

Single largest cause of perinatal morbidity and mortality in infants without anomalies in developed nationsRepresent more than 70% of all perinatal mortality and morbidity40% of preterm births follow preterm laborPrevalence: US = 11% Phil = 11.44% (POGS CNS)

PRETERM LABOR

PRETERM – refers to a fetus, a pregnancy, or a neonate, that is less than 37 weeks gestation (WHO, ACOG) and more than 20 weeks gestation

2 categories: Indicated = 20%

Spontaneous = 80%

PRETERM LABOR: categories

INDICATED*Follow medical or obstetric

disorders that place the mother or the fetus at risk.

*Preeclampsia (42%)

Fetal distress (26.7%)

Intrauterine growth restriction (10%)

Abruptio placenta (6.7%)

Fetal demise (6.7%)

SPONTANEOUS*Occur when there is no

underlying maternal or fetal illness

*Typically follow premature rupture of membranes, incompetent cervix, chorioamnionitis…

*Any prior spontaneous preterm delivery carries a 2.5 fold increased risk in a current gestation and even a 10.6 fold increase in preterm delivery <28 weeks AOG

PRETERM LABOR: risk factors

Previous preterm delivery

Low socioeconomic status

Vaginal bleeding

Nonwhite race

Multiple gestation

Low body mass index

Bacteriuria

Extremes of age (≤18 or ≥40 years)Genital colonization or infectionAbsent/inadequate prenatal careCervical injury or abnormalitySmokingUterine abnormality

PRETERM LABOR: risk factors

Previous preterm deliveryLow socioeconomic status

Vaginal bleeding

Nonwhite race

Multiple gestation

Low body mass index

Bacteriuria

Extremes of age (≤18 or ≥40 years)

Genital colonization or infection

Absent/inadequate prenatal care

Cervical injury or abnormality

Smoking

Uterine abnormality

* Nearly 50% of women with preterm deliveries have no identifiable risk factors…

PRETERM LABOR: diagnosis

CERVICAL CHANGES*Characteristic cervical changes before delivery: shortening, softening, progressive dilatation*Digital examination: failed to predict preterm labor because of the great variation between examiners *Transvaginal UTZ of the uterine cervix is a better predictor of preterm delivery

PRETERM LABOR: diagnosis

Preterm Prediction Trial, 1996*2 findings consistently associated with an

increase in preterm birth:

1. Cervical length <25 mm (10th percentile) to 30 mm (25th percentile)

2. Appearance of a funnel that comprises 50% or more of the total cervical length

PRETERM LABOR: diagnosis

BIOCHEMICAL/ ENDOCRINE MARKERS1. FETAL FIBRONECTIN (Ffn)

• A glycoprotein produced by the fetal chorion and localized to the maternal decidua basalis

• When disruption of the choriodecidual junction occurs, it is extravasated into cervical and vaginal secretions

• Rarely identified after 21 weeks gestation• Presence after 21 weeks AOG is strongly

associated with preterm delivery

PRETERM LABOR: diagnosis

2. SALIVARY ESTRIOL* estriol – “estrogen of pregnancy”* salivary estriol levels mirror the level of biologically active (unconjugated) estriol in the circulation* elevated levels of maternal salivary estriol (≥2.1 ng/ml) is predictive of preterm delivery in high risk women* studies show increased levels 2-4 weeks before delivery, whether term or preterm

PRETERM LABOR: diagnosis

3. CORTICOTROPIN-RELEASING

HORMONE (CRH)

* a hypophysiotrophic hormone that

stimulates ACTH production in the

pituitary

* demonstrated to increase 100-fold in

maternal serum in the 3rd trimester before

parturition

PRETERM LABOR: management

TOCOLYTIC THERAPY

ANTIBIOTICS

STEROIDS

TOCOLYTIC THERAPY

Mainstay of hospital therapy once preterm labor is suspected

Cannot be expected to prevent prematurity because they treat the symptom (contractions), not the underlying pathology

PRETERM LABOR: management

TOCOLYTIC THERAPYMain benefit: temporarily delay delivery (48-72

hours) to allow:

1. Administration of glucocorticoid therapy to improve neonatal outcome

2. Transfer of the mother to a tertiary facility that can best take care of a premature infant

3. Time to allow other treatments to work (e.g. antibiotics)

PRETERM LABOR: management

TOCOLYTIC AGENTS:1.Beta-mimetics:

Terbutaline sulfate (Bricanyl)

Ritodrine hydrochloride

Isoxuprine hydrochloride (Duvadilan/Isoxilan)

**consistently demonstrated an ability to prolong gestation by about 24-48 hours

**side effects include maternal pulmonary edema and neonatal intravascular hemorrhage

PRETERM LABOR: management

TOCOLYTIC AGENTS:2.Magnesium sulfate

**nonspecific calcium antagonist

**studies show no significant differences in delay in delivery when compared to beta-mimetics

**1st line of treatment in the US

**side effects include maternal hypocalcemia

**monitor for signs of magnesium toxicity

.

PRETERM LABOR: management

TOCOLYTIC AGENTS:3.Calcium-channel blockers (Nifedipine)

**contraindicated in maternal hypotension (<90/50)

4. Prostaglandin synthetase inhibitors:

Indomethacin

Sulindac

Ketorolac

5. Oxytocin antagonist – Atosiban

.

PRETERM LABOR: management

ANTIBIOTICS*Studies have linked urinary tract infections, intrauterine

infections, and vaginal microflora including bacterial vaginosis, with an increased risk for spontaneous preterm birth

*Proposed pathogenesis of infection-induced preterm labor: ascent of microorganisms from the cervix or vagina colonization of fetal membranes and decidua release of toxins production of cytokines production of prostaglandins which stimulate myometrial contractionPRETERM LABOR

PRETERM LABOR: management

ANTIBIOTICS*In PTL with intact membranes:

*shown to be of no beneficial effect

DISCOURAGED

*In PTL with Premature Rupture of Membranes

*shown to improve outcome for both mother and fetus

*beneficial in prolonging pregnancy and in decreasing

neonatal infectious morbidity

.

PRETERM LABOR: management

STEROIDS

*Use prior to preterm delivery has been shown to significantly decrease respiratory distress and neonatal mortality

*There is not enough evidence to evaluate the utilization of repeated doses of corticosteroids

*Present recommendation is only for a single course

*Dexamethasone, Betamethasone

PRETERM LABOR: management

POST-TERM PREGNANCY

TERM gestation: 37-42 weeks

POST-TERM: >294 days or 42 weeks• Frequency: 4-14% (2-7% at 43 weeks)• Parturition occurs at 280 days (40 weeks)

after 1st day of last menses only in 5%• Associated with increased perinatal morbidity

and mortality

POST-TERM PREGNANCY: diagnosis

Reliability of the Last Menstrual Period (LMP)

Use of ultrasound measurements (early = done <24 weeks gestation)

Assessment of amniotic fluid:*Volume – oligohydramnios?

* Character – stained?

ULTRASOUND:

*Fetal biometry/ fetal aging

*Amniotic fluid assessment

POST-TERM PREGNANCY: diagnosis

OLIGOHYDRAMNIOS:*AFI is below 5 cm*Associated with higher rates of intrapartum fetal distress and cesarean section*Meconium-staining: occurs in 37% of post-term pregnancies with normal AFI;increase to 71% when AFI is diminished

POST-TERM PREGNANCY: diagnosis

FETAL COMPLICATIONS:• Aberrations in fetal growth:

• Postmature-dysmature syndrome – wasting of subcutaneous tissue, meconium-staining, peeling of skin (undernourished neonate)

• Macrosomia - >4000 grams birth injuries

• Meconium-staining & pulmonary aspiration• 3-fold higher increased incidence in post-term

POST-TERM PREGNANCY

If (+)favorable cervix: labor induction between 41-42 weeks

If (+)unfavorable cervix: (a) do cervical ripening followed by labor induction; or (b) do twice weekly fetal monitoring DELIVERY if with fetal compromise

Use of UTZ: Biophysical Profile/ Score

POST-TERM PREGNANCY: management

PREMATURE RUPTURE OF MEMBRANES (PROM)

Spontaneous rupture of the membranes that occur before the onset of labor

Preterm PROMRupture of the membranes before 37 weeks

PREMATURE RUPTURE OF MEMBRANES: diagnosis

Diagnosis of membrane Diagnosis of membrane rupture is mainly clinicalrupture is mainly clinical

*other causes of vaginal discharge must be excluded

PREMATURE RUPTURE OF MEMBRANES: diagnosis

Diagnostic tests:1. Nitrazine paper – insert a sterile cotton tip applicator deep into the vagina touch it to the nitrazine paper

pH > 6.5pH > 6.5 consistent with ruptured membranes

False positive nitrazine paper test:False positive nitrazine paper test: increased pH such as in cases contaminated by blood, semen or alkaline substance, or if with bacterial vaginosis

PREMATURE RUPTURE OF MEMBRANES: diagnosis

2. Ferning

false positive result:false positive result: if the specimen is contaminated with cervical mucus (sample should be taken from the cul de sac or lateral vaginal walls)

PREMATURE RUPTURE OF MEMBRANES: diagnosis

3. Ultrasound evaluation

Ultrasound finding of oligohydramnios without fetal urinary tract malformation or fetal growth restriction highly suggestive of membrane rupture

* Gestational age should be established as soon as possibleClinical history and UTZ – estimate the gestational age, fetal weight, fetal position & residual amniotic fluid

* Evaluate for presence of advanced labor, chorioamnionitis, abruptio placenta, fetal distress

Expeditious delivery regardless of ageExpeditious delivery regardless of age

PREMATURE RUPTURE OF MEMBRANES: management

* If conservative management is pursued, patient must be admitted to a tertiary hospital

* Provisions for 24-hour neonatal resuscitation & intensive care

PREMATURE RUPTURE OF MEMBRANES: management

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