An observational study in Bariatric Surgery, Pregnency and Reproductive Health and Childbirth, sponsored by Helse Nord-Trøndelag HF. Recruiting at 3 sites in Norway. Open to female participants aged 18 Years to 45 Years. Per ClinicalTrials.gov, last updated 2026-10-20.
Sponsored by Helse Nord-Trøndelag HF · Observational
The goal of this observational study is to learn how bariatric surgery affects the health and nutritional status of women and their babies during pregnancy and after birth. The study will also investigate pregnancy complications and whether the time between surgery and pregnancy affects pregnancy outcomes.
The study includes pregnant women who have undergone bariatric surgery and pregnant women who have not had surgery.
The main questions this study aims to answer are:
Researchers will compare women with and without previous bariatric surgery to look for differences in:
Participants will:
The findings may help improve nutritional care and pregnancy follow-up for women who have undergone bariatric surgery.
The Maternal Outcomes after Bariatric Surgery (MOBS) study is a prospective, multicenter observational cohort study investigating maternal nutritional status, glucose regulation, gestational weight gain, pregnancy complications, and neonatal outcomes following bariatric surgery.
The study aims to include 210 pregnant women, comprising 70 women with previous bariatric surgery (Roux-en-Y gastric bypass or sleeve gastrectomy) and 140 pregnant women without previous bariatric surgery who had a prepregnancy body mass index (BMI) ≥25 kg/m².
Participants are recruited before gestational week 19 and followed throughout pregnancy and up to 12 weeks postpartum. Data are collected at several study visits during pregnancy and after delivery.
Maternal assessments include dietary intake, nutritional supplement use, anthropometric measurements, body composition assessed by bioelectrical impedance analysis (BIA), blood pressure, and biochemical markers of nutritional status. Dietary intake is assessed using food frequency questionnaires and 24-hour dietary recalls. Blood and urine samples are collected to assess vitamin and mineral status and other relevant biochemical parameters.
Continuous glucose monitoring (CGM) is performed for approximately 15 days during mid-pregnancy to assess glucose patterns, glycemic variability, and episodes of hypoglycemia.
Information on maternal health, pregnancy complications, gestational diabetes, hypertensive disorders of pregnancy, and delivery outcomes is obtained from questionnaires and medical records.
Neonatal assessments include birth weight, length, and biochemical markers of nutritional status measured in samples collected at birth.
The study will compare maternal and neonatal outcomes between women with and without previous bariatric surgery. Associations between nutritional status, dietary intake, glucose regulation, gestational weight gain, and pregnancy outcomes will also be investigated. Among women with previous bariatric surgery, the potential association between time since surgery and pregnancy outcomes will be explored.
The findings are expected to contribute to improved nutritional monitoring and clinical follow-up of women during pregnancy after bariatric surgery.
123 studies on the registry are indexed under Gestational Weight Gain; 20 are open to participants now.
This study's planned enrollment of 210 is below the median of 400 across 16 observational studies indexed under Gestational Weight Gain.
Browse Gestational Weight Gain studies →Helse Nord-Trøndelag HF is the lead sponsor of 26 studies on the registry; 4 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Nord Trøndelag Hospital Trust Namsos and Levanger Hospital St Olavs University Hospital Møre and Romsdal Hospital Trust, Ålesund Hospital
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Exclusion Criteria:
Other: Post-Bariatric Maternal and Infant Health Study
Other: Observation arm
Other: Post-Bariatric Maternal and Infant Health Study
Other: Observation arm
Comprehensive Nutritional and Pregnancy Monitoring in Women Following Bariatric Surgery This intervention involves systematic monitoring of nutritional status, gestational weight gain, and pregnancy outcomes in women who have undergone bariatric surgery (Roux-en-Y gastric bypass or sleeve gastrectomy). It includes blood and urine sampling, dietary assessments, body composition analysis, and continuous glucose monitoring throughout pregnancy and postpartum. The study also includes matched control groups of non-operated pregnant women and their newborns.
Comparing antropometri and Blood sampels between groups
Maternal Iron status
Ferritin (µg/L)
Time frame: At four time points: ≤19 weeks of gestation, 24-26 weeks of gestation, 30-34 weeks of gestation, and 6-12 weeks postpartum.
Maternal gestational weight gain following bariatric surgery, compared with non-operated controls.
Changes in maternal weight (kg) at the different timpoints
Time frame: 2.th, 3.th trimester and 6 weeks postpartum
Newborn birth weight
Birth weight (g)
Time frame: at birth
Birth length
Length (cm)
Time frame: at birth
Vitamin B12 concentration in neonatal cord blood
Vitamin B12 concentration (pmol/L) in cord blood from newborns of mothers with previous bariatric surgery compared with newborns of mothers without previous bariatric surgery.
Time frame: at birth
Plan to share: Undecided
No publications or documents are linked to this record.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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Helse Nord-Trøndelag HF