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Risk of pre‐eclampsia after gastric bypass: a matched cohort study
Author(s) -
Johansson K,
Wikström AK,
Söderling J,
Näslund I,
Ottosson J,
Neovius M,
Stephansson O
Publication year - 2022
Publication title -
bjog: an international journal of obstetrics and gynaecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.157
H-Index - 164
eISSN - 1471-0528
pISSN - 1470-0328
DOI - 10.1111/1471-0528.16871
Subject(s) - medicine , pregnancy , eclampsia , gastric bypass surgery , obstetrics , body mass index , hazard ratio , cohort , gynecology , obesity , gastric bypass , weight loss , confidence interval , genetics , biology
Objective To investigate whether gastric bypass before pregnancy is associated with reduced risk of pre‐eclampsia. Design Nationwide matched cohort study. Setting Swedish national health care. Population A total of 843 667 singleton pregnancies without pre‐pregnancy hypertension were identified in the Swedish Medical Birth Register between 2007 and 2014, of which 2930 had a history of gastric bypass and a pre‐surgery weight available from the Scandinavian Obesity Surgery Registry. Two matched control groups (pre‐surgery and early‐pregnancy body mass index [BMI]) were propensity score matched separately for nulliparous and parous births, to post‐gastric bypass pregnancies ( n pre‐surgery‐BMI = 2634:2634/ n early‐pregnancy‐BMI = 2766:2766) on pre‐surgery/early‐pregnancy BMI, diabetes status (pre‐surgery/pre‐conception), maternal age, early‐pregnancy smoking status, educational level, height, country of birth, delivery year and history of pre‐eclampsia. Main outcome measures Pre‐eclampsia categorised into any, preterm onset (<37 +0 weeks) and term onset (≥37 +0 weeks). Results In post‐gastric bypass pregnancies, mean pre‐surgery BMI was 42.9 kg/m 2 and mean BMI loss between surgery and early pregnancy was 14.0 kg/m 2 (39 kg). Post‐gastric bypass pregnancies had lower risk of pre‐eclampsia compared with pre‐surgery BMI‐matched controls (1.7 versus 9.7 per 100 pregnancies; hazard ratio [HR] 0.21, 95% CI 0.15–0.28) and early‐pregnancy BMI‐matched controls (1.9 versus 5.0 per 100 pregnancies; HR 0.44, 95% CI 0.33–0.60). Although relative risks for pre‐eclampsia for post‐gastric bypass pregnancies versus pre‐surgery matched controls was similar, absolute risk differences (RD) were significantly greater for nulliparous women (RD −13.6 per 100 pregnancies, 95% CI −16.1 to −11.2) versus parous women (RD −4.4 per 100 pregnancies, 95% CI −5.7 to −3.1). Conclusion We found that gastric bypass was associated with lower risk of pre‐eclampsia, with the largest absolute risk reduction among nulliparous women. Tweetable abstract In this large study including two comparison groups matched for pre‐surgery or early‐pregnancy BMI, gastric bypass was associated with lower risk of pre‐eclampsia.