Korean J Obstet Gynecol.
2009 Nov;52(11):1109-1116.
Interpregnancy interval after a previous preterm birth and subsequent preterm birth risk
- Affiliations
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- 1Department of Obstetrics and Gynecology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea. drmaxmix.choi@samsung.com
Abstract
OBJECTIVE
To investigate the recurrent preterm birth (PTB) risk in women with a history of previous PTB, and whether the interpregnancy interval or the indication for previous PTB is associated with the recurrent PTB risk.
METHODS
A retrospective analysis was conducted on a group of 325 women whose first delivery ended at preterm and subsequently delivered their second birth. Data regarding delivery dates, gestational age at delivery and indication for PTB in the first and second pregnancies, respectively, were collected from medical records. Interpregnancy interval was defined as the period of time between the first PTB and subsequent conception. The patients were divided into six groups based on the interpregnancy intervals (<6, 6-12, 12-24, 24-36, 36-48, >48 months).
RESULTS
The recurrent PTB rate in the study population was 24.3%, which was significantly higher than PTB rate in the control groups (primipara, 15.5%, P<0.001; multipara who delivered at term in their first pregnancy, 11.8%, P<0.001). The recurrent PTB rate was lowest in the 6-12 months interpregnancy interval group, and highest in the 36-48 months group. However, the rate of recurrent PTB was not significantly different among the six different interpregnancy interval groups (chi square test, P=0.394, linear-by-linear association test, P=0.343). In addition, there was no association between the indication for previous PTB and the recurrent PTB rate.
CONCLUSION
Although the risk of PTB was increased in women with a history of PTB, the risk was not influenced by the interpregnancy interval or the indication for previous PTB.
