A Case-Control Study on Risk Factors of Preterm Labor

Lee, Chang Ik; Koh, Kyung Sim; Lee, Won Ki

Abstract

BACKGROUND: The prevention of preterm deliveries still remains a major problem in ob-stetrics. The cause of preterm labor is poorly understood. Our purpose was to determine the risk factors for preterm labor associated with specific clinical and environmental factors.
METHODS
Using a case-control design, 54 women with preterm labor and 134 controls with term labor, who were admitted to the department of Obstetrics and Gynecology, Dan- kook University Hospital from January, 1996 to August, 1996. The study groups were inte- rviewed and their medical records were reviewed.
RESULTS
1. There were no significant differences of maternal age, maternal weight at 20 weeks of gestation and maternal weight gain at the time of delivery. 2. There were no significant differences between housewives and working women. But the physical workload of the preterm labor group was significantly higher than the control group ( 16.0% vs. 4.0% ). 3. There were no significant differences in the smoking habit of mother or her husba- nd. The passive smoking of the preterm labor group was significantly higher than the con- trol group ( 43.8% vs. 26.8% ). 4. In vaginal bleeding at pregnancy, the preterm labor group was significantly higher than the control group ( 15.7% vs. 2.3% ). Especially, the third trimester vaginal bleeding of the preterm labor group was significantly higher than the control group. 5. There were no significant differences in the number of previous fullterm deliveries, previous abortions, and living children between two groups. The experience of the previous preterm deliveries of the preterm group was significantly higher than the control group ( 11. 5% vs. 0.8% ). 6. There were no significant differences of medications, consumption of alcohol, coffee, tea, green-tea, cola and nutritional beverages, the experiences of coitus, defecation numbers and accidents during pregnancy between two groups. 7. There were no significant differences in the plasma concentrations of hemoglobin, hematocrit, white blood cells, and in the blood pressure, and the body temperature between two groups.
CONCLUSION
The risk factors of preterm labor were severe physical workload, vaginal bleeding at pregnancy, especially, the third trimester vaginal bleeding, and the experience of previous preterm deliveries.