We thank Dr Quinn et al for their interest in our study. Their letter offers a possible explanation for why women with prior abortion have an increased risk of spontaneous preterm delivery. They speculate that both surgical and medical evacuation of the uterus might result in injuries of the uterosacral ligaments and of the uterovaginal nerves, which could lead to an increased risk of preterm labor. They also state that “medical evacuation complicated by excessive uterine activity may increase the risk of preterm labor.” These statements raise at least 3 issues. First, they do not provide references to support the thesis that women undergoing surgical or medical evacuation have an increased risk of denervation of the lower genital tract. Second, the literature lacks data regarding the possible association between uterosacral ligament injuries (which is indeed correlated with pelvic organ prolapse), and risk of preterm birth. Lastly, if uterine activity related to medical evacuation is really associated with increased risk of preterm delivery, women with prior induction of labor should be at least as likely as those with prior medical abortion to have an increased risk for spontaneous preterm birth.

In our meta-analysis there were 3 main hypotheses to explain our findings.

• 1)
  

  Infectious diseases following surgical uterine evacuation can account for the increased risk. The increased risk could result from the overt or covert infection following surgical uterine evacuation.

  
  
• 2)
  

  The mechanical trauma to the cervix can lead to increased risk of cervical insufficiency.

  
  
• 3)
  

  Surgical procedures including curettage during dilation and evacuation may result in scar tissue that may increase the probability of faulty placental implantation.

We look forward to further discussion, ideas and research on this important topic.