Preterm Labor Ahmed Barefah Ahmed Al-Ghamdi Mohammed 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?

Prediction Assessment of risk factors Vaginal examination to assess the cervical status Ultrasound visualization of cervical length and dilatation 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.

1-Risk Factors 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 Other Risk Factors Multiple pregnancy: risk >50% Previous preterm delivery: risk 20- 40% Cigarette smoking: risk 20-30% Cervical incompetence Uterine abnormalities

1-Risk Factors Other 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.

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

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

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 B –Sympathomimetic (Ritodrine) Magnesium sulphate Indomethacin Nifedipine = Epilate Atosiban= Tractocile

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 Sulfate Magnesium sulphate is ineffective at delaying birth or preventing preterm birth, and its use is associated with an increased mortality for the infant.

Nitric Oxide Donors There 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: Tractocil Atosiban, a synthetic peptide, is a competitive antagonist of oxytocin at uterine oxytocin receptors.

Atosiban: Tractocil Atosiban - 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.

Nifedipine Nifedipine- 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

Nifedipine When tocolysis is indicated for women in preterm labor, calcium channel blockers are preferable to other tocolytic agents compared, mainly betamimetics.

Nifedipine 20mg 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.

Corticosteroids Antenatal 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.

Corticosteroids Two 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.

Conclusions Various 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 .

Conclusions If a tocolytic drug is used, ritodrine no longer seems the best choice.

Conclusions Other 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

Conclusions Maintenance tocolytic therapy has no proven effect. It cannot be recommended for routine practice.

Thank You team A