Preterm Labor

Ahmed BarefahAhmed Al-GhamdiMohammed Al-Talhi

Definition

Preterm labor is the presence of contractions of sufficient strength and frequency to effect progressive effacement and dilation of the cervix between 20 and 37 weeks' gestation

WHO

Preterm Labor

Incidence : 9-11%

• Spontaneous : 40-50%

• PROM : 25-40%

• Obstetrically indicated : 20-25%

Preterm Labor

Most mortality and

morbidity is experienced

by babies born before 34

weeks.

Major Risks Of Preterm Delivery

• Death • Respiratory distress syndrome • Hypothermia • Hypoglycaemia • Necrotising enterocolitis • Jaundice • Infection • Retinopathy of prematurity • Intraventricular hemorrhage

Can preterm labor be predicted?

Prediction1. Assessment of risk factors

2. Vaginal examination to assess the cervical status

3. Ultrasound visualization of cervical length and dilatation

4. Detection of foetal fibronectin in cervicovaginal secretions

1-Risk Factors While the exact cause of

preterm labor is often unknown, there is strong evidence that intrauterine infection may play a role in very early preterm labor.

Bacterial Vaginosis Bacterial vaginosis increased the

risk of preterm delivery >2-fold . Risks were higher for those

screened at <16 weeks than those at <20 weeks of gestation

1-Risk Factors

Multiple pregnancy: risk >50%

Previous preterm delivery: risk 20- 40%

Cigarette smoking: risk 20-30%

Cervical incompetence

Uterine abnormalities

Other Risk Factors1-Risk Factors

Young age of mother - less than 16 years of age.

•Lower socioeconomic class.

Reduced body mass index (BMI) - BMI less than 19.0.

Antiphosphlipid syndrome.

Obstetric complications, including hypertension in pregnancy,antepartum haemorrhage, infection, polyhydramnios, foetalabnormalities.

Other Risk Factors

1-Risk Factors

2-Vaginal examination

Digital examination is the traditional method used to detect cervical maturation, but quantifying these changes is often difficult.

3-Vaginal U/S

Vaginal ultrasonography

allows a more objective

approach to examination

of the cervix.

Prevention

Prevention of Preterm Labor

Women at increased risk of preterm delivery may be identified by various risk factors in the obstetric history and treated.

General measures

• Tobacco cessation

• Improved nutritional status

• Aggressive treatment of UTIs

• Patient education

17 Hydroxy -Progesterone Caproate

Prophylactic use of 17 hydroxy progesterone caproate to prevent preterm labor revealed a significant decrease in preterm birth .

Weekly injection or daily suppositories

Treatment Of Vaginosis

Treatment of asymptomatic abnormal vaginal flora and bacterial vaginosis

with oral clindamycin early in the 2nd trimester significantly reduces the rate of late miscarriage and spontaneous preterm birth.

Diagnosis

3 criteria to document PTL(20-37w)

1-Regular uterine contractions occur

at 4/20 min. or 8/60 min. Plus:

progressive change in the cervix.

2- Cervical dilatation > 1 cm 3- Effacement _ 80%.

Diagnosis

>

Vaginal U/S+ Fibronectin Test Suspected preterm labor with no

cervical changes :Negative fetal fibronectin +

Cervical length > 30 mm

the likelihood of delivering in the next week is less than 1%.

Thus most women with a negative test can safely be sent home without treatment.

Treatment •Inhibition of labor• Corticosteroid• Antibiotics •Others.

Inhibition Of Labor•Bed rest :DVT

•Hydration &sedation

• Tocolytics

Most Efforts to Prevent Preterm Labor Not Effective

Until effective strategies are found, efforts should be aimed at preventing newborn complications by :

• Corticosteroids• Antibiotics against group B strep • Avoiding traumatic deliveries. • Delivery in a center with experienced

resuscitation teams and neonatal intensive care

Is Tocolysis Better Than No Tocolysis For Preterm Labour?

• It is reasonable not to use tocolytic drugs, as there is no clear evidence that they improve outcome. However, tocolysis should be considered if the few days gained would be put to good use, such as completing a course of corticosteroids, or in utero transfer

Tocolytics Most authorities do not

recommend use of tocolytics at or after 34 weeks' .

There is no consensus on a lower gestational age limit for the use of tocolytic agents.

Choice Of Tocolytic Drug

Nifedipine = Epilate

Atosiban= Tractocile

B –Sympathomimetic (Ritodrine)

Magnesium sulphate

Indomethacin

Choice Of Tocolytic Drug

If a tocolytic drug is used, ritodrine no

longer seems the best choice.

Atosiban or nifedipine appear

preferable as they have fewer adverse

effects and seem to have comparable

effectiveness.

B -Sympathomimetic Agents.

• Maternal: pulmonary edema, myocardial ischemia, arrhythmia, and even maternal death.

• Fetal : arrhythmia, cardiac septal hypertrophy , hydrops, pulmonary edema, and cardiac failure. hypoglycemia, periventricular-intraventricular hemorrhage, and fetal and neonatal death. .

Magnesium sulphate is ineffective

at delaying birth or preventing

preterm birth, and its use is

associated with an increased

mortality for the infant.

Magnesium Sulfate

Nitric Oxide DonorsThere is insufficient evidence to

support the routine

administration of nitric oxide

donors (nitroglycerin )in the

treatment of preterm labor.

Indomethacin Compared with ritodrine there is

insufficient evidence for any differential effect on delay in delivery, but indomethacin does seem to have fewer maternal adverse effects than the beta-agonists

Indomethacin Fetal risk:Premature closure of the ductus.Renal and cerebral vasoconstriction.Necrotising enterocolitis

Common with high dose and prolonged exposure.

Indomethacin Indomethacin can be used as a second-line tocolytic agent in early gestational age preterm labors.

Indomethacin Indomethacin may be a first-

line tocolytic in:

• Associated polyhydramnios :

( to have renal effects of indomethacin)

Atosiban: TractocilAtosiban, a synthetic

peptide, is a competitive antagonist of oxytocin at

uterine oxytocin receptors.

Atosiban: TractocilAtosiban - compared with beta-agonists-

has:

Little difference in the effect of these agents on

delayed delivery

Fewer maternal adverse effects than beta-agonists,

such as chest pain, palpitations , tachycardia ,

hypotension , dyspnoea ,vomiting , and headache.

NifedipineNifedipine- compared with ritodrine -

has:

Higher delaying of delivery for >48 H.

Lower risk of RDS &Neonatal jundice.

Lower admission to NN ICU

Fewer maternal adverse effects

NifedipineWhen tocolysis is indicated for women in

preterm labor, calcium channel blockers

are preferable to other tocolytic agents

compared, mainly betamimetics.

Nifedipine20mg initial

10-20 mg /4-6 h

Epilate capsule :10mg

Epilate retard Tablet: 20 mg

Maintenance Tocolysis Is Not Recommended For Routine Practice.

There is insufficient evidence for any firm conclusions about whether or not maintenance tocolytic therapy following threatened preterm labor is worthwhile. Therefore maintenance therapy cannot be recommended for routine practice.

CorticosteroidsAntenatal corticosteroids are associated

with a significant reduction in rates of

RDS, neonatal death and

intraventricular haemorrhage, although

the numbers needed to treat increase

significantly after 34 weeks' gestation.

Corticosteroids

The optimal treatment-delivery

interval for administration of

antenatal corticosteroids is

after 24 hours but < 7 days after

the start of treatment.

CorticosteroidsTwo 12 mg doses of betamethasone

given IM 24 hours apart, Or

Four 6 mg doses of dexamethasone

given IM 12 hours apart

Antibiotics

Group B Streptococci (GBS) Prophylaxis

All patients in preterm labor are considered at high risk for neonatal GBS sepsis and should receive prophylactic antibiotics regardless of culture status.

Group B Streptococci (GBS) Prophylaxis

The goal of this strategy is to prevent neonatal sepsis, and not to prevent preterm birth.

ConclusionsVarious strategies that have been used to prevent or treat preterm labor, haven't proven effective.

Tocolysis should be considered only for 2 days- if needed - for corticosteroids therapy , or in utero transfer to a tertiary center .

ConclusionsIf a tocolytic drug is

used, ritodrine no longer

seems the best choice.

ConclusionsOther drugs with fewer adverse effects and

comparable effectiveness are now

recommended

Atosiban or nifedipine have been

recommended

endomethacin may be used as a 2nd line

tocolytic or if there is polyhydramnios

ConclusionsMaintenance tocolytic therapy has no proven effect.

It cannot be recommended for routine practice.

Thank You

team A

Thank You

team A