Because many preterm births are caused by recurrent conditions, medical professionals consider a previous premature birth to be one of the biggest risk factors for premature births that might happen later.
Why does a history of preterm labor make future preterm labor more likely?
There are a few reasons why the reasons for a previous premature birth could be relevant in later pregnancies. The first is purely physical – if, say, a woman’s cervix was weakened by an abdominal injury, which contributed to a first premature birth, it’s totally possible that it could also cause a second premature birth. The same thing is true if there were hormonal factors in a previous preterm labor, or any other physical reason that might not have changed or gone away during the time between pregnancies.
The other factor is lifestyle – weight, smoking, and drinking can all contribute to preterm delivery, and women who don’t change the lifestyle factors that might have been a part of a previous preterm birth are more likely to face another preterm delivery.
Sources
- “Thinking about pregnancy after premature birth.” MarchofDimes. March of Dimes Foundation, Jan 2013. Web.
- MM Adams, et al. “Rates of and factors associated with recurrence of preterm delivery.” JAMA. 283(12):1591-6. Web. Mar 2000.
- Sophie MS Liem, et al. “Cervical Pessaries for the Prevention of Preterm Birth: A Systematic Review.” Obstet Gynecol Int. 2013: 576723. Web. 2013.