Optimal timing for delivery in case of placenta previa: late-preterm or early-term?

In response to the original article published in January 2015. Balayla J, Wo Bl, Bedard MJ. A late-preterm, early-term stratified analysis of neonatal outcomes by gestational age in placenta previa: defining the optimal timing for delivery. J Matern Fetal Neonat Med 2015.

We have read with great interest the article by Balayla et al. [1] where the authors compared neonatal outcomes following delivery at 35–36 weeks of gestation (WG) to 37–38 WG in women with placenta previa (PP). Balayla et al. cite the paucity of international guidelines as the reason behind their study and refer to the ones published by the Society for Maternal Fetal Medicine (SMFM) and the Royal College of Obstetrics and Gynaecology (RCOG). According to the authors, the SMFM recommends delivery between 36^0/7–37^6/7 WG in cases of non-complicated PP (table 1 in the report), citing Spong et al. [2]. However, it is worth noting that Spong et al. clearly mention that their document “reflects the opinions of the workshop participants, and its contents do not necessarily represent the official views of the SMFM” [2]. The authors consider the evidence of the “recommendations” to be level B, even though no Randomized Controlled Trials or cohort studies were cited in the references. Moreover, we could not find the reference for the presumed RCOG guidelines cited by the authors.

On the other hand, we identify many problems with the data on which Balayla et al. based their study. Indeed, these data from the CDC's linked birth-infant death are strictly American and date back to more than 10 years, which clearly affects their external validity. In addition, important information are missing, such as the definition and classification of PP, the reasons behind the deliveries at 35 and 36 WG, the incidence of complications during pregnancy and labor. Finally, the main author, Balayla J., has recently used the same data to publish a similar report that has many overlappings with the current one [3].

Since such data is difficult to interpret, we think it would have been interesting for the authors to perform, at their own university-affiliated center, a retrospective analysis that includes obstetric and neonatal outcomes. Such a study would have allowed them to compare outcomes with another population without PP, delivering at a similar WG (35–36 versus 37–38 weeks), allowing for a proper analysis of neonatal outcomes by WG in PP.

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.