The PLART study: incidence of preterm labor and adverse pregnancy outcomes after assisted reproductive techniques—a retrospective cohort study
Even though assisted reproductive techniques represent one of the greatest achievements in modern medicine, the risk of preterm birth related to these pregnancies is about twice as high. This must be highlighted and further investigated to optimize the management of both mothers and newborns.
The purpose of this study was to compare adverse pregnancy outcomes after assisted reproductive techniques (ART) and spontaneous conceptions, focusing on the incidence of preterm births (PTB) and distinguishing between iatrogenic and spontaneous events.
This retrospective cohort study analyzed single births of one Italian hospital. The incidence of PTBs in ART pregnancies, divided into iatrogenic procedures, spontaneous preterm labors and preterm premature ruptures of the membranes (pPROMs), was compared with the non-ART control group. The incidence of other adverse pregnancy outcomes and the types of delivery were also reported and compared.
Of the 11,769 single births included, 2.39% were conceived by ART. The incidence of PTBs was 4.74% for spontaneous pregnancies and 12.8% for ART pregnancies (aOR 1.93; 95% CI 1.29–2.88). The percentage of iatrogenic procedures was 27.78% in the ART-PTBs’ group and 30.88% in the non-ART-PTBs’ controls. ART pregnancies showed an increased incidence of pPROMs (6.40% versus 2.41%), preterm labors (2.85% versus 0.93%), hypertensive disorders of the pregnancy (8.19% versus 2.32%), placenta previa (3.20% versus 0.59%), cesarean sections (28.47% versus 16.27%) and vacuum extractions (10.32% versus 5.19%).
Singleton ART pregnancies have a higher risk of PTB which is mostly linked to a higher incidence of pPROMs and spontaneous preterm labor. The concurrency of a demonstrated higher risk of hypertensive gestational disorders and placenta previa suggests that placental development plays an important role in the pathogenesis of PTB.
KeywordsAssisted reproductive techniques Preterm birth Preterm labor Preterm premature rupture of membranes Gestational hypertension Placenta previa
Adverse pregnancy outcome
Assisted reproductive techniques
Body mass index
Preterm labor after assisted reproductive techniques
Preterm premature rupture of the membranes
The authors thank Dr. Elisabetta Fabbri for her assistance with statistics and for the great availability.
We certify that all authors equally contributed to the realization of the study. In particular: AC data collection. PG, FS and BT project development. GN manuscript writing. ES data collection and manuscript writing. MS manuscript editing.
Compliance with ethical standards
Conflict of interest
All authors declare that there is no conflict of interest.
Given its retrospective design, this article does not contain any studies with human participants or animals performed by any of the authors. All data were collected and analyzed keeping anonymity, according to European laws on privacy. The study was approved by the Local Ethics Committee (Comitato Etico di Area Vasta Romagna) in February 2018. According to the Italian Authorisation of the Guarantor n.9/2016 and taking into account the logistic impossibility to reach out to all the women included in the study, given the large number of the sample, the investigators were exonerated from the request of informed consents.
- 8.Registro Nazionale Procreazione Medicalmente Assistita (2016). Available from: https://old.iss.it/binary/rpma/cont/C_17_pubblicazioni_2762_allegato.pdf. Accessed 12 Mar 2019