PRETERM LABOUR: A STUDY OF ETIOLOGICAL RISKFACTORS AND PERINATAL OUTCOME

Shilpa Dhingra 1 , Bhumika Shukla 2 and Sudha Salhan 3 . 1. Associate Professor, NDMC Medical College and Hindu Rao Hospital, Delhi. 2. Senior Resident, NDMC Medical College and Hindu Rao Hospital, Delhi. 3. Professor, NDMC Medical College and Hindu Rao Hospital, Delhi. ...................................................................................................................... Manuscript Info Abstract ......................... ........................................................................ Manuscript History


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deliveries, low social-economic status, extremes of maternal age, (<17, >35 years of age) and present obstetric complications like over distension of uterus, pre-eclampsia and antepartum haemorrhage are thought to be mainly responsible for onset of preterm labour [6].
Aims and objective:-1. To find out the incidence, etiological risk factors responsible for pretermlabour. 2. To evaluate the perinatal outcome in preterm births.

Material and Methods:-
This prospective observational clinical study was carried out in 946 cases, between 20 weeks to less than 37 weeks of gestation, who presented with preterm labour, preterm premature rupture of membrane and with conditions where labour was iatrogenically induced prematurely were included in the study. The patients who presented with following signs and symptoms were included in the study:-1. Painful uterine contractions four in 20 min with progressive cervical changes. 2. Cervical effacement of more than 80% and dilatation more than 1 cm.
The duration of study was 6 months. All the cases were admitted in the labour room and the progress of labour was monitored. Obstetric management was done as per the findings in the individual case. Paediatricians were available at the time of delivery. All subjects and their babies were followed throughout their hospital stay. Associated maternal risk factors and perinatal outcomes were analyzed. Babies were transferred to premature baby care unit for neonatal care and neonatal outcome was analyzed.

Results:-
Total number of delivery in 6 months study period were 4382. Out of 4382 deliveries, 946 were preterm birth (21.5%). It was observed that 40% women were from poor social-economic status. 44.5% of cases had pregnancy duration of 34 to 37 weeks. 70% cases had some associated risk factor responsible for preterm labour. PPROM, hypertension and anemia were the common risk factors associated with preterm labour (Table 1). 73.2% delivered vaginally and 26.8% cases were delivered by caesarean section. Perinatal mortality was 17.8% (Table 2). Early neonatal death was seen in 7.1% of cases. 4.4% of preterm deliveries came with intrauterine death. Antepartum haemorrhage, hypertension and fetal congenital malformation were common causes of still births (Table 3) whereas respiratory distress syndrome, birth asphyxia and septicaemia were common causes of early neonatal deaths (Table  4). Neonatal outcome was directly proportional to gestational age (Table 5) and birth weight of the baby. Neonatal mortality was highest in the babies born with birth weight less than 750 grams.

Discussion:-
This clinical prospective study was carried out in a tertiary care teaching hospital for duration of 6 months. In the present study, the incidence of preterm birth was 21.5% which was higher than reported by Bangal et al [7] and Devi et al [8] where incidence were 13.2% and 12.18% respectively. The higher incidence could be due to many preterm high risk pregnancies referred to our hospital and associated risk factors necessitating a preterm birth for maternal and fetal indication. In the present study, 40% women were from poor socio-economic status whereas in a study reported from Bangal et al [7]95% of cases were from poor socio-economic class. The reason for high poor socioeconomic class was that their study was carried out in a rural tertiary care teaching hospital catering patients from surrounding villages.
In the present study, it was found that 70% of preterm deliveries had associated risk factors. Molly et al [9](1970) found that 67% of premature births had some obvious risk factors associated with preterm labour and Bangal et al [7](2012) found the associated risk factor in 57% of cases. In the present study the common risk factors were preterm premature rupture of membrane followed by hypertension, anemia and antepartum haemorrhage.
In the present study, 44.5% of preterm births were between 34 to < 37 weeks of gestation. Similar reports were reported by Bangal et al [7]. In their study 50% cases had pregnancy duration of 32 to 34 weeks. The reason for the selective rise in the "late preterm" group possibly was due to an increase in medical reasons necessitating a preterm delivery, changes in obstetric practice or both [10].
The perinatal mortality among premature babies is very high in developing countries due to low birth weight and prematurity. In the present study it was observed that perinatal mortality was directly related to birth weight and  [7].
In the present study, the perinatal mortality was 17.8% as compared to 42.4% seen in a study conducted by Bangal et al [7]. The reason for low perinatal mortality in our hospital was due to availability of better neonatal care unit. The main risk factor associated with fresh still birth in the present study are acute placental insufficiency as a result of antepartum haemorrhage and severe hypertension. Fetal congenital malformation, severe anemia and hepatitis were responsible for antepartum fetal death. The most common cause for early neonatal death was respiratory distress syndrome seen in 38.3% of cases followed by birth asphyxia and septicaemia. Similar results were observed by Bangal et al (2012) [7] in their study.
Preventive measures like regular antenatal check-ups, screening of high risk cases, diagnosis and treatment of lower genital tract infections [12][13] by performing prophylactic encirclage in cases of cervical incompetence [14], use of short term tocolysis and glucocorticoids for improving lung maturity [15,16], improving maternal nutrition leads to reducing the incidence of preterm labour and thereby reducing perinatal mortality. Neonatal septicaemia can be reduced by improving the aseptic conditions in the labour room and in the neonatal care unit and by use of broad spectrum antibiotics in preterm labour. Birth asphyxia can be reduced by improvement in neonatal care facilities.

Conclusion:-
Preterm onset of labour has a multifactorial etiology. Early detection and correction of risk factors like control of blood pressure in preeclampsia, correction of anemia, treatment of cervicovaginal infections and asymptomatic bacteriuria, avoidance of coitus in late pregnancy and cervical encirclage in proven cases of cervical incompetence can reduce the incidence of preterm labour. Maternal betamethasone for enhancing the fetal pulmonary maturity and reducing the incidence of respiratory distress syndrome in new born babies should be administered. All preterm deliveries should be conducted in tertiary care hospital where better perinatal care is available.

Declaration of interest statement:-
The authors report no declarations of interest.