**6. Management of preterm labour**

The mangement of preterm labour fall into five areas; the use of tocolysis, adminstration of antibiotics, admistration of antenatal steriods, magnisum sulphate for neuroprotection and finally the considerations for the mode of delivery.

### **7. Tocolysis**

It is important to realise that the aim of tocolysis in modern obstertics is limited to gain few days to allow admistration of antenatal steriods which proved to reduce perinatal morbidities in preterm birth and allow in utero transfer (**Table 1**).


*Preterm Labour DOI: http://dx.doi.org/10.5772/intechopen.96049*

#### **Table 1.** *Tocolytics.*

#### **8. B2-agonists**

Ritodrine and other b-agonists as terbutaline, salbutamol were used as tocolytic agent but currently not recommeded as first line due to its maternal and neonatal side effects. They act on b2 receptors in myometrial smooth muscles via a cAMP dependent mechanism leading to reduction in the intracellular calcium causing muscular relaxation. Cochrane review on B2-agonists concluded that they decrease the number of preterm births within 48 hours but not within 7 days [1, 17, 18].

Maternal side effects include; palpitations and arrhythmias, chest pain, hypotension, flushing, nausea, headache, pulmonary oedema, hypokalaemia and hyperglycaemia. Neonatal side effects include; tachycardia, hypotension, hypoglycaemia, hypocalcemia and ileus. It is not proved that B2-agnosists are associated with neonatal periventericular haemorrhage [18].

#### **9. Indomethacin**

It is a nonsteroidal anti-inflamatory agent which inhibit cyclo-oxygenase enzyme and subsequently reduces myomeytrial prostaglandins concentration which inturn down regulates myometrial cells gap junctions, down regulates oxytocin receptors and reduces intracellular calcium levels. It has better tocolytic effect and better safety profile than b-agonists but its routine use is limited due to the associated fetal side effects [18].

Maternal side effects include; risks of peptic ulcerations, thrombocytopenia and postpartum haemorrhage and allergic reaction. Fetal side effects include; premature closure of ductus arteriosus. There is risk of neonatal necrotizing enterocolitis, intraventericular haemorrhage and renal dysfunction [18].

#### **10. COX (cyclo-oxygenase)-2 inhibitors**

It is a nonsteriodal anti-inflammatory agent which act specifically on cycloxgenase-2 enzyme which is upregulated in preterm labour. The mechanism of action is simillar to indomethacin but with better maternal side effect profile. Its routine use is limited due to fetal concerns over premature closure of the ductus and renal idysfunction [18].

#### **11. Atosiban**

Atosiban is an oxytocin analogue competitively blocks oxytocin and vasopressin receptors leading to reduced intracelluar calcium and lesser prostagladins production. It is recommended and licenced in preterm labour [1, 18, 19]. Its side effects include; maternal nausea, vomiting, hot flushes, hypotension and dizzness. It has simillar effectivness to B2-agonists and nifidipine but with a safer profile however, it is more expensive and given intravenously [1, 18].

#### **12. Nifedipine**

It is a calcium channel blocker that is proved to be effective in reducing preterm birth with lesser side effects compared to B2-agonists. It is admnistered orally and it is considered first line treatment option [1, 18]. The side effects of its use include; headache, dizzness, ankle odema, and constipation.
