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Prior term delivery increases risk of subsequent recurrent preterm birth: An unexpected finding
Author(s) -
Suff Natalie,
Xu Vicky X.,
Dalla Valle Giorgia,
Carter Jenny,
Brennecke Shaun,
Shennan Andrew
Publication year - 2022
Publication title -
australian and new zealand journal of obstetrics and gynaecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.734
H-Index - 65
eISSN - 1479-828X
pISSN - 0004-8666
DOI - 10.1111/ajo.13504
Subject(s) - preterm delivery , term (time) , medicine , premature birth , obstetrics , pediatrics , pregnancy , gestational age , fetus , biology , physics , genetics , quantum mechanics
Background Women with a prior pregnancy at term are generally considered to be at reduced risk for subsequent spontaneous preterm birth (sPTB), whereas a previous sPTB is a major predictor for a future sPTB. Aims The objective of this study was to investigate the risk of recurrent sPTB in women with a prior term birth and a subsequent sPTB. Materials and Methods This is a retrospective cohort study conducted at St Thomas’ Hospital in London, UK. There were 430 women included: 230 with a term birth (caesarean section or vaginal delivery) preceding a sPTB (term + sPTB group) and 200 with a prior sPTB only (sPTB only group). The primary outcome was sPTB, <37 weeks gestation. Results Of the term + sPTB group, 38.7% (89/230) had a recurrent sPTB compared to 20% (40/200) in the sPTB only group ( P < 0.0001), with a relative risk (RR) of 1.9. Of women who had a term caesarean section and a subsequent PTB, 50% (30/60) had a further sPTB (RR 2.5 compared to the sPTB only group), while 34.7% (59/170) of women who had a term vaginal birth and subsequent sPTB, had a further sPTB (RR 1.7 compared to the sPTB only group). Conclusion In women who have had a previous sPTB, the risk of a recurrence is much higher than in women with a prior term birth. The aetiology of PTB may be different in this subgroup of women and needs to be further elucidated to determine how best to identify and treat them.