Evaluation of efficacy of transdermal Nitroglycerine in the treatment of preterm labour

INTRODUCTION: Obstetrics is a fine art built on the facts gathered by scientific research. In the era of modern Obstetrics where there has been a rapid advancement in all specialities, preterm labour remains an enigma for the obstetricians of today. The social and emotional cost of perinatal mortality and morbidity associated with preterm birth is immeasurable. Ideally preterm labour should be prevented. However pharmacological inhibition of preterm labor remains an effective method to delay preterm delivery and improve neonatal outcome until a most effective means of prevention is identified. Since the Tocolysis has both potential benefits and side effects to neonate and mother, their use should be based on well designed controlled clinical studies. AIM OF THE STUDY: Aim of care around preterm birth does not always involve prevention of preterm labour and birth. In situation where clinical condition makes it desirable to prolong pregnancy, primary out come considered is time saved to * Seek advice from a perinatal care unit * Institute therapy to improve fetal lung maturity * If necessary move mother to centre with neonatal intensive care unit. Preterm fetus need glucocorticoids to enhance lung maturity. This can be achieved if delivery is postponed by 24 - 48 hours. Inhibition of uterine contraction at least for 2 days may therefore be regarded as optimal acute tocolysis. A great number of drugs are used to inhibit preterm labour. Aim of our study is to * Evaluate the effect and safety of transdermal nitroglycerine in acute tocolysis. * Effect of transdermal nitroglycerine on maternal and neonatal outcome. MATERIALS AND METHODS: STUDY DESIGN: It is a prospective randomized controlled trial. The study was conducted in Annal Gandhi Memorial Hospital, Trichy from August 2008 to July 2009. 100 patients with preterm labour randomly selected from patients attending antenatal OPD and from labour ward. 50 patients recruited for nitroglycerine patch and another 50 patients for bed rest alone. Both the groups received intramuscular corticosteroids. In view of the ethical issue, written informed consent was obtained. INCLUSION CRITERIA: 1. Gestational age between 28 to 34 wks as determined by menstrual dates, clinical examination, USG. 2. Uterine contractions: 2 contractions in 10 minute period, each contraction lasting for 40 sec. 3. Progressive cervical effacement upto 75%. 4. Cervical dilatation upto 3 cm. 5. Intact membranes. EXCLUSION CRITERIA: Maternal Factors: 1. Rupture of Membrane, 2. Infection, 3. Cervical dilatation greater than 3 cm, 4. Antepartum hemorrhage, 5. Pregnancy induced hypertension, 6. Chronic hypertension, 7. Cardiac disease, 8. Previous caesarean section, 9. Renal disease, 10. Pulmonary disorder – Asthmatics, ARDS. Fetal Factors: 1. Multiple gestation, 2. Fetal death / distress, 3. IUGR, 4. Congenital anomalies, 5. Polyhydramnios / Oligohydramnios, 6. Erythroblastosis. RESULTS: Study was designed with total sample of randomly selected 100 cases who were in Preterm labour, out of which 50 females were randomly allotted for Nitroglycerine patch in group A and another 50 patients in group B observed with bed rest alone. All patients on study were given corticosteroids. Prophylactic antibiotics also were given to all patients. CONCLUSION: Labour inhibiting drugs may not treat the cause of preterm labour but they only treat the symptoms i.e. uterine contractions. As these agents make the uterus refractory to stimuli for a short time the perinatal outcome is improved. In this clinical trial, the idiopathic spontaneous preterm labour whose onset was at 30 to 34 weeks of gestation had responded well to tocolytic therapy and neonatal outcome improved and no maternal mortality was observed. The maternal side effects were reversed on discontinuation of the drug. The drug had provided the fetus a valuable opportunity of being inside the mother’s womb for a period enough to make the lungs mature by administration of exogenous steroids. However decrease in the incidence of preterm labour lies in the identification of high risk patients, improving the socio-economic standard, better antenatal care, education and early detection of the onset of preterm labour. On evaluation of transdermal nitroglycerine on acute tocolysis, it is found that nitroglycerine patch is absolutely safe and successful in achieving complete tocolysis. 62 Nitroglycerine is not only safe but also has a very minimal side effects like headache on mother. It has no untoward side effect on neonate. Neonatal outcome is good in all respects like apgar score, birth weight, less neonatal admission in nitroglycerine therapy. To conclude transdermal nitroglycerine has a very good role to play as an acute tocolytic in the treatment of preterm labour and should be considered as first line drug of choice