Bariatric surgery is the most clinically and cost-effective treatment for severe obesity, resulting in sustained significant weight loss associated with health benefits such as remission of diabetes and reduced cardiovascular and cancer risk. According to National Bariatric Surgery Registry data 50% of female patients who have bariatric surgery are of child-bearing age. Given the known impact of obesity on fertility and pregnancy outcomes, improving fertility can be a reason given for bariatric surgery.
Current clinical guidance/consensus advises women to wait 12-18 months post-surgery before trying to conceive due to concerns associated with the rapid weight loss post-surgery. It is also advised that women who conceive post-bariatric surgery have consultant-led obstetric care and nutritional supplementation and monitoring adjusted during pregnancy. However, it is not known if this guidance is followed. Our recent study using routine primary care data suggested that guidance is not followed in a general adult post-bariatric surgery population. However, this has not been explored in a pregnant post-bariatric surgery population. There is also a need for more robust epidemiological data on outcomes from pregnancies post-bariatric surgery and in particular little is known about longer term outcomes for children of women who have had bariatric surgery.
The findings from this feasibility work are needed to develop a National Institute for Health Research grant application to conduct a series of matched-cohort studies to investigate maternal/child outcomes from post-bariatric surgery pregnancies using CPRD.
Note the terms of our funding for this work are purely for a feasibility study (Research Capability Funding).
We aim to use CPRD, HES APC and the mother-baby link to explore the feasibility of investigating maternal and child outcomes from pregnancies in women post-bariatric surgery. All analyses will be descriptive via either counts and percentages, mean (SD) or median (IQR). We will not report counts of <5.
Objectives are:
1. Examine the numbers of women and timings of pregnancies post-bariatric surgery in CPRD GOLD and Aurum and/or HES APC.
2. Describe the patient characteristics of women with pregnancies post-bariatric surgery, in terms of year, surgical procedure, age, region, IMD, ethnicity group, parity, latest BMI recorded pre-surgery and post-surgery (and the timing of the record).
3. For the pregnancy outcomes (listed in next section) occurring in ≥10% of women post-bariatric surgery, we will report the proportion of these women with each outcome by age group (5-year bands) and IMD quintile.
4. Describe whether we can match women with pregnancies post-bariatric surgery each to 3 pregnant women that year of the same BMI category (<30, 30-34.9, 35-39.9, ≥40kg/m2; latest in last 3yrs) pre-surgery, and also to 3 pregnant women that year with the same BMI category post-surgery (latest measure 3yrs pre-pregnancy). We will explore whether we can additionally match on exact age, ethnicity, IMD quintile, assisted reproduction (yes/no), and will relax the criteria if not possible. We will exclude BMI records measured during the second or third trimester and pregnancies with <12 months history at the GP practice before the pregnancy. We will briefly describe the patient characteristics of those matched without surgery (as per objective 2).
5. Estimate the numbers of child health records via linkage from the mothers with history of bariatric surgery (using the mother-baby link), lengths of follow-up and completeness and frequency of weight, height/length and co-morbidity recording occurring in ≥10% of the children.
For the pregnant women: miscarriage; stillbirth; prematurity; delivery type; intrauterine growth restriction; SCBU/NICU admission; congenital malformations; small/large for gestational age; maternal weight; gestational diabetes mellitus; gestational hypertension; pre-eclampsia; hyperemesis gravidarium; perinatal haemorrhages; postnatal depression/mental health problems; alcohol/substance misuse; nutritional markers (full blood count, vitamin D, calcium, vitamin B12, folate and ferritin levels, vitamin K, copper, zinc and selenium levels).
For the linked babies over follow-up: weight; height/length; and co-morbidity (for example, cerebral palsy; developmental delay; physical disability) recording.
Helen Parretti - Chief Investigator - University of East Anglia
Kathryn Richardson - Corresponding Applicant - University of East Anglia
Kathryn Richardson - Collaborator - University of East Anglia
CPRD GOLD Mother-Baby Link;HES Admitted Patient Care;Patient Level Index of Multiple Deprivation;CPRD Aurum Mother-Baby Link;Practice Level Index of Multiple Deprivation (Standard)