Poster Session 1
Category: Medical/Surgical/Diseases/Complications
Poster Session 1
Isabelle S. Hardy, MD, MSc, FRCSC (she/her/hers)
Postdoctoral Research fellow
Division of Maternal Fetal Medicine, Department of Obstetrics and Gynaecology, University of British Columbia.
Vancouver, British Columbia, Canada
Jessica Liauw, FRCS, MD, MSc
Assistant Professor and Maternal Fetal Medicine specialist
Division of Maternal Fetal Medicine, Department of Obstetrics and Gynaecology, University of British Columbia.
Vancouver, British Columbia, Canada
Olof Stephansson, MD, PhD
Professor and Senior Physician in Obstetrics and Gynaecology
Clinical Epidemiology Division, Department of Medicine Solna, Karolinska Institutet
Stockholm, Stockholms Lan, Sweden
Martin Neovius, PhD
Professor
Clinical Epidemiology Division, Department of Medicine Solna, Karolinska Institutet
Stockholm, Stockholms Lan, Sweden
Kari Johansson, PhD
Assistant Professor
Clinical Epidemiology Division, Department of Medicine Solna, Karolinska Institutet
Stockholm, Stockholms Lan, Sweden
Jennifer Hutcheon, PhD
Associate Professor
Division of Maternal Fetal Medicine, Department of Obstetrics and Gynaecology, University of British Columbia.
Vancouver, British Columbia, Canada
We linked nationwide bariatric surgery, birth, and other health registries from Sweden. Births (2013-2021) after maternal bariatric surgery were paired to control births with 1:1 matching for parity, pre-surgery body mass index, diabetes, and a propensity score of sociodemographic characteristics and maternal comorbidities. Births were classified as FGR using two definitions: 1) a postnatal Delphi consensus definition of FGR (Beune et al., 2018), and 2) a latent class model-based definition that combined neonatal anthropometry, adverse neonatal outcomes, and maternal risk factors. We also examined a measure of small fetal size that does not necessarily imply pathology, small-for-gestational-age birth (SGA, < 10th percentile).
For each definition, conditional logistic regression was used to estimate the association between bariatric surgery and the odds of FGR with 95% confidence intervals. Proportions of adverse neonatal outcomes amongst SGA births were compared between births after bariatric surgery and matched controls.
Results:
We included 5,258 post bariatric surgery births and 5,258 matched control births. Bariatric surgery was associated with increased odds of SGA birth (13.3% vs. 7.7%, respectively, odds ratio (OR) 1.85 [95% CI: 1.62, 2.11]). However, SGA births after bariatric surgery experienced fewer adverse neonatal outcomes than SGA births in controls (Table 1). When using the more rigorous definitions of FGR, the association between bariatric surgery and FGR was less pronounced (6.1% vs. 4.6% using Delphi definition, OR 1.35 [95% CI: 1.14, 1.61]) or no longer present (5.5% vs. 5.1% using latent class definition, OR 1.09 [95% CI: 0.92, 1.30]).
Conclusion:
Preconception bariatric surgery was associated with increased odds of SGA birth, but these births had lower risks of adverse outcomes. The use of more rigorous definitions of FGR suggests that preconception bariatric surgery may not be associated with pathological FGR.