TOPLINE:

Women who underwent a preterm full-dilation caesarean delivery (FDCD) after previous spontaneous preterm birth (sPTB) had a higher risk for recurrent sPTB before 37 and 34 weeks of gestation than those who had a preterm vaginal birth or CD before the second stage of labour.

METHODOLOGY:

• Researchers conducted a retrospective cohort study to evaluate whether a previous preterm FDCD is associated with a higher risk for recurrent sPTB in the subsequent pregnancy than a prior preterm vaginal birth or CD before the second stage of labour.
• They identified 240 women with a history of sPTB through a database search who attended two high-risk PTB surveillance clinics in the UK between 2010 and 2024.
• Women were categorised into three groups on the basis of their previous mode of sPTB: preterm FDCD (n = 21), preterm vaginal birth (n = 108), and preterm CD with cervical dilation under 10 cm (n = 111).
• The primary outcome was recurrent sPTB before 37 weeks of gestation; secondary outcomes included sPTB before 34 weeks of gestation.
• Transvaginal ultrasound was used to assess CD scars in a subgroup of women with a preterm FDCD.

TAKEAWAY:

• Overall, the rate of recurrent sPTB before 37 weeks of gestation was higher among women who underwent a preterm FDCD than among those who had a preterm vaginal birth and preterm CD with cervical dilation under 10 cm (38.1% vs 15.1% and 13.8%; P < .05 for all).
• After adjusting for potential confounders, women who underwent a preterm FDCD had 4.4-fold and 5.1-fold higher odds of recurrent sPTB before 37 weeks of gestation than those who had a preterm vaginal birth and preterm CD with cervical dilation under 10 cm, respectively (P < .05 for both).
• Before 34 weeks of gestation, women who underwent a preterm FDCD had 16.6-fold and 5.7-fold higher odds of recurrent sPTB than those who had a preterm vaginal birth and preterm CD with cervical dilation under 10 cm, respectively (P < .05 for both).
• In a subgroup of women with a preterm FDCD, 76.9% of CD scars were located within the cervix or less than 5 mm above the internal cervical ostium, and 70% of these women experienced mid-trimester shortening of cervical length (≤ 25 mm) and/or sPTB or spontaneous late miscarriage.

IN PRACTICE:

"It is important that clinicians are aware of this increased risk of recurrent sPTB and arrange appropriate preconception counseling and antenatal surveillance with interventions to prevent recurrence," the authors wrote.

SOURCE:

This study was led by Amrita Banerjee, Fetal Medicine Unit, Elizabeth Garrett Anderson Wing, University College London Hospital, London, England. It was published online on January 19, 2026, in Acta Obstetricia et Gynecologica Scandinavica.

LIMITATIONS:

The retrospective design of the study may have introduced selection bias, potentially affecting the risk estimates. Recruitment from two specialised PTB surveillance centres may have limited the generalisability of the findings to broader obstetric populations. The strict inclusion criteria reduced the sample size of CD groups, leaving the study underpowered to detect certain differences between the groups.

DISCLOSURES:

This study received support from Tommy's Charity at the Tommy's National Centre for Preterm Birth Research. One author reported receiving consulting fees and being a member of the advisory board for Prena.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.