1. Definition:

PTL is said to occur when labour takes place before completed 37wks of gestation.

2. Incidence:

(In U.K. is about 7%).

3. Etiology:

• Up to 45% of PTLs there is no known cause (idiopathic).
• But there are maternal and fetal associated factors in which PTL occurs.

3.1. Maternal factors:

1. Hypertension (whether essential or PIH).
2. Chronic nephritis.
3. Diabetes.
4. Heart disease.
5. Congenital malformation of  the uterus.
6. Malaria and febrile diseases.
7. Low social class.
8. Smoking.
9. APH (abruptio placentae and placenta praevia).
10. Cervical incompetence.

3.2. Fetal causes:

1. Multiple pregnancy.
2. Polyhydramnios.
3. Congenital malformation.
4. Rh. isoimmunization.

An important cause of PTL is iatrogenic cause (when the obstetrician decides to deliver a pregnant lady before term for a genuine indication).

4. Clinical picture:

• The pt. will present with labour pains, one uterine contraction every 3-5 minutes with or without rupture of the membranes, she may be having one of the above mentioned predisposing factors.
• Preterm problems may present as either preterm labour or premature rupture of the membranes.

5. Diagnosis:

• When labour is established or when the membranes are ruptured or there is a large leak of amniotic fluid there is no diagnostic difficulty.
• Speculum examination.
• Vaginal examination.

6. Management:

• 3 major factors determine the outcome:
  • Gestational age.
  • The condition of the baby at birth.
  • The availability & quality of neonatal care.

• Suppression of PTL:
  • Bed rest.
  • Valium 5mg (tab. or injection) is given. Pethedine & morphine contraindicated.
  • Tocolytics:
    • B-sympathomimetic agent (salbutamol and ritodrine). The B-sympathomimetic drugs will inhibit uterine contractions. Salbutamol is given as a start as infusion at a rate of 4 micrograms per minute and increased by 4 micrograms every 10min until uterine contractions are suppressed. The dose is maintained for 6hrs and then the patients is shifted to oral salbutamol every 8hours for one week. Because the B-sympathomimetics cause vasodilatation, cardiac acceleration and a rise in blood glucose, they cause:
      • Tachycardia.
      • Hyperglycemia.
      • Hyper insulinemia.
      • Pulmonary edema.
      • Cardiac ischemia.
      • So the B-sympathomimetic agents are contraindicated in patients who have:
        • Cardiac disease.
        • Hypertension.
        • Diabetes.
        • Abruptio placentae.
        • Any infection.
        • A patient with IUFD.
    • Ethanol infusion is given intravenously as 1.25gms per kg body wt. per hour for 12-24hrs and is followed by oral route of 30gms every 4hrs for another 24hrs.

• Steroids:
  • PTL implies the birth of a preterm baby, who is at increased risk of developing respiratory distress syndrome (RDS). This risk is reduced when dexamethasone is administered to the patient with PTL.
  • Dexamethasone 12mg is given 12hourly for 24hrs (2doses) and labour should be stopped for at least 24hrs. for the steroids to act and increase the lung surfactant.
  • If the membranes are intact, they should be kept intact as long as possible tocolytics, bed rest, sedation and steroids.
  • If the membranes are ruptured, speculum and vaginal examination should be performed to exclude cord prolapse.
  • For the second stage of labour a good episiotomy should be made and forceps delivery done.

• Caesarean Section (C/S):
  • There is strong indication for C/S in the delivery of preterm fetuses. C/S is indicated if:
    • Gestational age is between 26-31wks and the presentation is breech.
  • • There is APH.
  • PTL in patients who are beyond 32/52 depends on other factors associated, vaginal delivery is the option and C/S is indicated if there are other factors necessary to deliver the patient by C/S.

• Special Care Baby Unit (SCBU):The availability of SCBU is very essential for these preterm babies. If there is no SCBU in the hospital to deal with these babies, it is better to refer the patient with the baby in utero to another hospital where SCBU is available then to deliver her and send the baby in an incubator.

7. Premature rupture of membranes (PMRM):

• This is spontaneous rupture of membranes before the onset of labour.
• Cause is unknown.
• PMRM causes the onset of labour through the process of prostaglandin release.
• Diagnosis:
  • Speculum examination.
  • Nitrazine paper test (alkaline).

• Management:
  • This depends on the duration of pregnancy.
  • If the pregnancy is beyond 34weeks labour should be stimulated.
  • If the pregnancy is less than 34weeks efforts should be made to prevent the onset of labour:
    • Bed rest.
    • Sedation.
    • No V/E (but S/E).
    • Observation for any signs of intrauterine infection (temp., WBC, offensive V/D).