Maternal and fetal/neonatal outcomes in pregnancy, delivery and postpartum following bariatric surgery and comparison with pregnant women with obesity: a study protocol for a prospective cohort

Background Being obese can lead to various complications during pregnancy, such as Gestational Diabetes Mellitus (GDM), pregnancy induced hypertension (PIH), Pre-Eclampsia (PE), and Large Gestational Age (LGA). Although bariatric surgery is an effective way to treat obesity, it can also result in complications and may be linked to having small for gestational age (SGA) babies. This cohort study protocol aims to compare the maternal and fetal/neonatal outcomes of two groups of Iranian pregnant women: those who have undergone bariatric surgery and those who are obese but have not had bariatric surgery.Methods In this study Pregnant women (< 14 weeks' gestation) (n = 38 per group) are recruited either from one of the obesity clinic (exposure group = with a history of bariatric surgery) or primary healthcare clinics in Tehran city (comparison group = pregnant women with obesity and and no history of bariatric surgery). Dietary intake and nutrient status are assessed at < 14, 28, and 36 weeks. Maternal and fetal/neonatal outcomes are compared between the two groups, including gestational diabetes, preeclampsia, preterm labor, intrauterine growth restriction, severe nausea and vomiting, abortion, placenta previa and abruption, venous thrombosis, vaginal bleeding, cesarean delivery, meconium aspiration, and respiratory distress. Maternal serum levels of ferritin, albumin, zinc, calcium, magnesium, selenium, copper, vitamins A, B9, B12, and 25-hydroxy Vit D are checked during 24th to 28th weeks. Maternal and neonatal outcomes, including height, weight, head circumference, fetal abnormality, infection, small or large fetus, low birth weight, macrosomia, NICU admission, and total weight gain during pregnancy, are measured at birth. Maternal and offspring outcomes, including weight, height, head circumference, total weight gain during pregnancy, newborn diseases, postpartum bleeding, breastfeeding, and related problems, are assessed 6 weeks after delivery. Child's weight, height, and head circumference are followed at 2, 4, 6, 8, 10, and 12 months after birth. Maternal stress, anxiety, and depression are assessed with the DASS-21 questionnaire, and physical activity is evaluated using the PPAQ questionnaire in the first and third trimesters.Discussion By assessing the levels of micronutrients in the blood of pregnant women along with the evaluation of pregnancy outcomes, it is feasible to gain a more accurate understanding of how bariatric surgery affects the health and potential complications for both the mother and the fetus/newborn. This information can help specialists and patients make more informed decisions about the surgery. Additionally, by examining issues such as stress, anxiety, and depression in women undergoing surgery, this study can contribute to recognizing these problems, which can also affect pregnancy outcomes.