Preterm birth and its associated risk factors. A study at tertiary care hospitals of Karachi, Pakistan

Objective: To study the factors associated with the risk of preterm birth among local population of Karachi, Pakistan. Methods: This case control study was carried out on all those patients who were admitted in the post-partum wards of Civil Hospital and Abbasi Shaheed Hospital Karachi, during the period of January to May 2011. A total of 600 patients were part of this study. All those women who had preterm delivery (delivery at 37 weeks of gestation) were grouped together as case-group (n=300), while women who had term delivery (delivery ?37 and 42 weeks of gestation) were grouped as control-group (n=300). Data was collected by the help of a questionnaire which included questions related to the previous and current gestational history of the mothers, their nutritional status, drug addictions, urogenital, dental or systemic diseases they suffered, along with any physical or emotional stress they experienced during pregnancy. Last menstrual period and ultrasound reports were brought into use to calculate the precise gestational age of the baby. Data collected from the two groups were then compared to find out the possible risk factors of preterm delivery. Results: A total of 600 subjects were divided into two equal groups of cases (n=300) and controls (n=300). There were 30 (10%) patients in the case-group and 33(11%) patients in the control-group who were above 35 years of age (p 0.05). At the time of delivery, 111(37%) cases and 51(17%) controls weighed 50kg (p 0.01). There were 264 (88%) cases and 117 (39%) controls with a haemoglobin level 10gm/dL (p 0.01). In the case-group, 15 (5%) patients had a history of previous multiple preterm deliveries, 24 (8%) had one previous preterm delivery, and 261 (87%) had no previous preterm delivery. In the control-group, no patient had a history of multiple preterm deliveries, 15(5%) had one previous preterm delivery, and 285 (95%) had no previous preterm deliveries (p 0.05). Common symptoms experienced in the gestational period in the case-group were dizziness/weakness (228; 76%), pain/malaise (213; 71%) and emotional stress such as anger (207; 69%). In the control-group the distribution was as follows: dizziness/weakness (168; 56%), emotional stress such as anger (165; 55%) and pain/malaise (141; 47%) (p 0.01). In the case-group, 69 (23%) women consumed fish, milk and pulses on a weekly basis, 177 (59%) on a monthly basis, and 54 (18%) did not take them at all. In the control-group, 174 (58%) patients consumed fish, milk and pulses on weekly basis, 90 (30%) on a monthly basis, and 36 (12%) did not take them at all (p 0.01). About 66 (22%) patients from the case-group and 21 (7%) in the control-group had evidence of periodontal disease on physical examination (p 0.05). Conclusion: Low maternal weight, multiple previous preterm deliveries, periodontal diseases, maternal anaemia, physical and emotional stress are among the factors associated with the risk of preterm birth among the local population delivering in tertiary care, governmental hospitals of Karachi, Pakistan