RESULTS

Table 1: Feto-Maternal Outcome of Tocolysis

Figure 1: Feto-maternal outcome of tocolysis

The mean time taken to lessen or stop uterine contractions sufficiently was significantly less in the Nifedipine Group (1.64±1.015 hrs) than in the Isoxsuprine Group (11.94±10.557 hrs). p<001.

There is a significant difference between the mean prolongation of pregnancy by Nifedipine (46.13±17.78 days) and by Isoxsuprine (27.35±20.60 days). p<0.001 which is very highly significant. The mean birth rate was in Nifedipine group was 2.618±0.366 and in Isoxsuprine 2.156±0.624 this observed difference was highly significant.

Maternal Mortality was nil in both the groups. The Perinatal mortality was 1(2%) in Nifidipine, significantly lower as compared to Isoxsuprine group 8 (16%).

The successful tocolytic effect was significantly higher in Nifedipine group(100%) as Compared to Isoxsuprine (70%).

Table 2: Maternal Side Effects Across the study groups

Table 2: Maternal Side Effects Across the Tocolysis were headache, flushing, tachycardia (defined as increase in pulse rate by more than 20bpm), hypotension (defined as drop in diastolic BP by more than 15mmHg), palpitation and dizziness

Table 3: Perinatal Side Effects Across The Study Groups

Table 3: Of the perinatal side effects observed during the study, only fetal tachycardia can probably be attributed to the drug side effects, other parameters, since were seen at birth, may not be due to the effect of the drugs. The confirmation could not be done, as the blood drug levels were not estimated.

Table 4: Range Of Efficacy Of The Tocolytic Drugs Used In The Study

Thus Nifedipine has been excellent as a tocolytic without any maternal or fetal side effects in 44% cases and without any failure cases. Isoxsuprine has been excellent in 36% cases with 30% failure cases.

DISCUSSION

Preterm labour remains one of the unconquered frontiers in the present day Obstetrics. It refers to the onset of uterine contractions of sufficient strength and frequency to effect progressive dilatation and effacement of the cervix before 37 completed weeks of gestation (WHO recommendation1972). In India, for legal purposes viability is defined as any gestation carried beyond 28 weeks.

Preterm labour complicates 5-10% of pregnancies and accounts for about 75-80% of perinatal morbidity and mortality (after exclusion of genetic and anatomical defects).

The incidence of preterm labour amongst the labour room admissions (patients in labour) in the present study was found to be 6%. This is similar to the others data.

Unfortunately, the incidence of preterm labour has changed very little over the last 30 years. Isoxsuprine was the first beta mimetic drug used to inhibit preterm labour in 1961. In the light of its unpleasant side effects and efficacy its therapeutic value is now found to be limited. Ulmsten et al first used Nifedipine, a calcium channel blocker as a tocolytic in 1980. Based on the results of the studies included in the Cochrane Review-2005, Issue 2 ^8,9,10 comparing the effects of Calcium channel blockers (mainly Nifedipine) with that of other tocolytics (mainly beta mimetics), calcium channel blockers are shown to be more effective tocolytic agents with improvement of some clinically important neonatal side effects and marked reduction in adverse maternal side effects.

Tocolytic Efficacy: The tocolytic efficacy was analyzed under six categories: Successful tocolysis, Duration of prolongation of pregnancy from starting of therapy, Mean gestational age at delivery, Cervical status as a factor in determining tocolytic efficacy, Maternal side effects of the therapy, Fetal/neonatal side effects of the therapy. In the present study, successful tocolysis defined as prolongation of pregnancy by more than 48 hours, during which parenteral corticosteroids were given to hasten lung maturity, was achieved in 100% with Nifedipine and 70% with Isoxsuprine. The mean prolongation of pregnancy in the present study was 46.13±17.78 days with Nifedipine vs. 27.35±20.60 days with Isoxsuprine, which is highly significant (p<0.001). Following are the Results of Different Studies

All the above studies show a greater prolongation of pregnancy with Nifedipine and our study results are also similar. Maternal Outcome: The present study found hypotension, tachycardia, palpitation, flushing (hot flushes), headache and dizziness as common side effects. There was no case of drug discontinuation in the Nifedipine group due to side effects but 3 cases in the Isoxsuprine group required discontinuation due to persistent tachycardia and hypotension. Mean gestational age at delivery and Mean Birth weight were significantly more in Nifedipine group vs. Isoxsuprine group (p<0.001) in our study which is similar to the study by Rayamajhi et al. Other adverse effects noted were neonatal jaundice, respiratory distress syndrome, birth asphyxia and necrotizing enterocolitis (NEC) in both the groups as shown in Table 3 (results and observations). Similar adverse effects have been reported in other clinical trials also but it is difficult to say whether these effects are due to the tocolytic agents or due to the prematurity of the babies. In the present study there were 1 (2%) perinatal mortality in the Nifedipine group and 8 (16%) in the Isoxsuprine group. In both the groups babies were preterm <34 weeks. Out of the 8 babies in the Isoxsuprine group 6 were delivered due to tocolytic failure. In the Nifedipine group the baby that died was a still born due to cord prolapse.

CONCLUSIONS

In our study we have found Nifedipine as a better, safer and effective tocolytic compared to Isoxsuprine in the management of preterm labour.

However, further trials are required involving larger population and with different dose regimen to throw more light on this aspect.

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