Preterm labor is defined as the onset of labor (regular uterine contractions associated with cervical changes) occurring after 24 weeks and before 37 completed weeks of gestation.

In Jordan, accurate statistics regarding the incidence of preterm labor and its impact onmaternal and fetal morbidity and mortality are lacking.

Worldwide, preterm labor occurs in 6-8% of pregnancies; preterm labor with intact membranes accounts for 30-40% of pretermLabor Preterm birth accounts for 70% of cases of neonatal morbidity and mortality.

There are three major etiological factors that contribute to preterm labor: Preterm pre-labor rupture of membranes (PPROM) Spontaneous preterm labor in pregnancies with intact membranes Complications of pregnancy that severely jeopardize fetal and sometimes maternal health and mandate delivery

Previous preterm labor, the recurrence risk of preterm labor varies from 15% to 40%after one prior preterm birth and significantly increases with two or more preterm labors.Uterine overdistension, e.g., multiple pregnancy, hydramnios Vaginal infection, bacterial vaginosis has been shown to be associated with preterm labor. In recent years, the most popular theory for one cause of preterm labor has been intrauterine infection.

Uterine abnormalities (septum, fibroid, etc.) History of incompetence of the cervixUrinary tract infections Poor nutrition, smoking and poor weight gain during pregnancyYoung maternal age

History takingFollow the history taking in the booking procedure in the Antenatal Care chapter and keep in mind the following important data:

Date of the last menstrual period History of previous pregnancy with occurrence of preterm laborHistory of risk factors, e.g., multiple pregnancyWarning symptoms (vaginal bleeding, ROM)History suggestive of vaginal infection: vaginal discharge, dysuria

* Follow the steps of physical examination as mentioned in the Antenatal Care chapter, keeping in mind the following signs:- Abdominal examinationUterine contractions, frequency and durationPalpate renal angle for tenderness

Perform a sterile vaginal examination provided there are no contraindications (e.g.,bleeding) to assess:Cervical effacement and dilationStation and nature of the presenting part

Documented uterine contractions, 4 per 20 minutesDocumented cervical changes: cervical effacement or cervical dilatation of 2 cm or more

* Laboratory investigationsCBCABO grouping and Rh typeUrine analysis and cultureSwab of the lower vagina for culture

- Ultrasound Asses fetal gestational age and weightDocument presentationAssess amniotic fluidAssess placenta site and gradeAssess cervical lengthRule out the presence of any congenital malformations

Once the diagnosis has been made, the clinician must identify women who need delivery and women who need tocolysis and steroids to enhance lung maturity

Cervix is dilated 4 cm.Membranes are ruptured. The woman has an acute medical or surgical condition such as thyrotoxicosis, heart disease or PIH.The woman has a temperature 38C or clinical evidence of chorioamnionitis. Fetal demise

Fetal congenital anomalies incompatible with lifeSevere fetal distress Severe IUGRBleeding suggestive of abruptio placentaeSevere pre-eclampsia

Membranes are intact, ANDGestational age is < 34 weeks, ANDThere is no overt maternal or fetal infection, ANDCervix is dilated < 4 cm, ANDThere is no evidence of placental insufficiency or maternal disease to justify delivery.

* Prophylactic measuresIdentify women at risk for preterm labor:Treat vaginal infections.Provide education to the woman to identify early symptoms and signs, so that women are admitted early to allow initiation of tocolytic therapy.

- First aid managementAdmit the woman to the labor ward and put her on complete bed rest.Insert an IV cannula.Give steroids if the gestational age is < 34 weeks.

If the gestational age is > 34 weeks:Allow deliveryIf the gestational age is < 34 weeksTocolysis, Uterine tocolytic agents- sympathomimetic agents, e.g., ritodrine (Yutopar)Calcium channel blockers (nifedipine)Oxytocin receptors antagonist (Atosiban)MgSO4Prostaglandin synthetase inhibitors-Antibiotics-Corticosteroids

If a tocolytic drug is used, nifedipine appears preferable over ritodrine as it has fewer adverse effects and seems to have comparable effectiveness.(Recommendation grade:A)

* Calcium channel blockers (nifedipine)A growing body of evidence suggests that nifedipine as an oral agent is very effectivein suppressing preterm labor with minimal side effects. The only side effects areheadache, cutaneous flushing, hypotension and tachycardia. The latter two side effectscan be partially avoided by making certain the woman is well hydrated.

How to use?Put the woman on complete bed rest. Give nothing by mouth for at least the first 46 hours. Start IV tocolysis as follows:

Dissolve 3 ampules (150 mg) of ritodrine (Yutopar) in 500 mL D5W or Ringers lactate Start the IV infusion at a rate of 0.050.1 mg/min (1020 drops/min andincrease by 0.05 mg (10 drops) each 10 minutes until: Contractions stopInfusion reaches a maximum of 0.35 mg/min (70 drops/min)Pulse rate reaches or exceeds 130/bpmToxicity appears, e.g., tachycardia, nausea, vomiting and/or irritability

Once an adequate dose is reached, continue for 12 hours from the last contraction.There is no evidence to support the use of oral tocolysis after the cessation of uterine contractions; i.e., the maintenance treatment is not recommended for routine practice.(Recommendation grade: A)

Do not begin tocolysis using -sympathomimetics if the woman presents with:Symptomatic maternal cardiac disease, especially outflow obstructionArrhythmiaHyperthyroidismSevere bleedingSevere anemiaEclampsia and severe pre-eclampsiaUncontrolled insulin dependent diabetesTaking monoamine oxidase inhibitorsAsthma and is already taking -sympathomimetics

*Complications of - sympathomimetics (ritodrine)Pulmonary edemaHeart failure- A strong diuretic such as Furesamide 40 mg ampoule should be available when using ritodrine as a tocolytic agent.

In the above situations, it is highly recommended that the case be referred to a higher level.

Begin MgSO4 tocolysis by an intravenous bolus of 6 gm in 100150 mL of a standard IV solution over 2030 minutes. Maintain MgSO4 infusion at 13 gm/hour to titrate cessation of contractions for approximately 24 hours. Monitor woman for muscle weakness (absent reflexes), double vision, andrespiratory insufficiency in addition to the monitoring advised below. Calcium gluconate (1 gm IV push over a few minutes) may be administered to reverse MgSO4 toxicity if it occurs and must be available if MgSO4 is used.

Agents that inhibit prostaglandin synthetase are quite effective tocolytic agents.Indomethacin is the most commonly used. Its use can result in oligohydramnios and premature closure of the ductus arterious. However, short term use may be acceptable.

Indomethacin dose: A loading dose of 50100 mg is followed by a total 24-hourdose not greater than 200 mg. Most studies have limited the use of indomethacinto 2448 hours duration (rectal suppository/12 hours).

- Ritodrine hydrochloride (Yutopar)Solution: 150 mg of ritodrine in 500 mL of D5W (0.3 mg/mL): IV piggybackParenteral administrationInitial dose: 0.050.1 mg/min (10-20 drops/min)Titrating dose: Increase by 0.05 (10 drops) every 10 min until contractions cease or unacceptable side effects occur; maximum dose, 0.35 mg/min (70 drops/min) or maternal pulse of 130 bpmMaintenance dose: 12 hrs at maximum dose

NifedipinePreparation: Oral gelatin capsules of 10 or 20 mgLoading dose: 30 mg; if contractions persist after 90 min, give an additional 20 mg (second dose); if labor is suppressed, a maintenance dose of 20 mg is given orally every 6 hrs for 24 hrs and then every 8 hrs for another 24 hrsFailure: If contractions persist 60 min after the second dose, treatment should be considered a failure

- AtosibanIV bolus of 0.9 ml of 7.5 mg/ml solution in the first minute, then (300g/min) 12 ml/hrof 7.5 mg/ml solution for three hours then (100g/min) 4 ml/hr of 7.5 mg/ml for 48

- Magnesium sulfate (MgSO4)Parenteral administrationInitial dose: 6 gm over 2030 min Titrating dose: 2 gm/hr until contractions cease; follow serum levels (57 mg/dL); maximum dose, 4 gm/hr Maintenance dose: Maintain dose for 12 hours, then 1 gm/hr for 2428 hrs; may switch to oral -agonist therapy before discontinuing

The woman should be observed for the following: Pulse rate should not exceed 130/bpm. The woman should be observed every 15 minutes until the maximum dose is reached, then every 30 minutes for one hour, and then every hour. Monitor temperature to guard against pyrexia, every eight hours Abdominal tenderness in the absence of contractions, every eight hours BP, every hour during IV medication; should not be < 100/60 mmHg Respiratory rate should not exceed 24/minute. Pulmonary edema is possible, especially if steroids are used and it is a multiple pregnancyChest auscultation

Fetal heart rate variations: Normal is 120160 bpm. Use continuous external fetal monitoring (EFM) when available.Fetal movements Excessive vaginal dischargeVaginal bleedingNausea and vomitingUrinary output; every hour during IV infusion, at least 30 cc/hourTotal fluid intake should not exceed 125 cc/hour (3000 mL/day) of mixed fluids (IV and oral).

Transfer the woman to the antenatal ward.Require absolute bed rest to start, then bed rest with bathroom privileges.Allow normal diet.

Vital signs every 30 minutes for two hours; if normal, then per routine BP should not be < 100/60 mmHgMaternal pulse (should not be higher than 120/bpm)Vaginal discharge or bleedingUterine contractions (should be less than 6 per hour)Urinary output (should be > 30 cc/hour or > 100 cc/4 hours)

Ultrasound twice weeklyNST dailyConsultations according to associated problemsMonitor intake of all medications

Stop tocolytic medication and allow the woman to progress. The obstetric specialist should attend the delivery; the pediatric specialist should be advised and be present for the delivery. Remember to notify the neonatal service to prepare for a preterm neonate.If the woman initially presents with cervical dilation of 4 cm or more, admit her to the labor ward and allow her to progress with a vaginal delivery if there is no contraindication. The obstetric specialist should attend the delivery; the pediatric specialist should be advised and be present for the delivery.If there is any contraindication to a vaginal birth, perform a cesarean delivery.

- Antibiotic therapyIt is reasonable to use prophylactic antibiotics in women with preterm labor in an attempt toprevent the progression of silent infection to clinical amnionitis and the risk of fetal infection.

- Corticosteroid therapyDexamethasone IM 4 mg/6 hours for 4 doses or betamethasone IM 12 mg/12 hours for 2doses promotes fetal lung maturation for pregnancies less than 34 weeks gestation

Conditions for DischargeAt least 48 hours have passed since tocolysis was achieved and labor pains have resolved.Stable general conditionNo associated pathology and not under treatment (e.g., antibiotics) Educate the woman to:Monitor uterine activityCount fetal movements and watch for decreased movementStop sexual activity

Evaluate vaginal dischargeEvaluate vaginal bleedingDecrease physical activityUnderstand the necessity of delivering in a hospitalUnderstand the importance of correctly complying with medical treatment and prenatal care

- Care of the Preterm NeonatePreterm neonates are subjected to many problems:HypothermiaRespiratory distress

Follow steps of neonatal resuscitation according to guidelines (refer to Normal Labor chapter).Transport the neonate immediately to the NICU in a portable incubator.Provide an appropriate thermal environment. Provide adequate oxygenation by oxygen mask in case of respiratory distress, cyanosis or oxygen saturation less than 88% or by ambu bag in case of irregular gasping respirations, apnea, persistent cyanosis despite 100% oxygen supplementation by oxygen mask or heart rate < 100 bpm.Flow of oxygen should be 510 L/min. Monitor O2 saturation if pulse oximeter is available (required O2 saturation 8895%).

Check the neonates glucose level using a glucose strip within the first hour after birth to exclude hypoglycemia. If the neonate is hypoglycemic, give D10W 2mL/kg IV over 24 min and transport immediately to the NICU in a portable incubator.

Do not wait for symptoms of hypoglycemia to appear in preterm babies inorderto start IV glucose