Obesity is graded according to a BMI measurement >35 kg/m2. Morbid obesity is classified as a BMI measurement >40 kg/m2 (National Institute for Health and Care Excellence (NICE), 2014). It is predicted that 48% of adults in the UK will be classified as obese by 2030 (Wang et al, 2011). Obesity is strongly linked to metabolic diseases (cardiovascular disease, diabetes mellitus, non-alcoholic fatty liver disease and polycystic ovary syndrome (PCOS)), musculoskeletal and respiratory disorders and psychological illness; losing weight can improve these co-morbidities (Whitehead and Bano, 2019). Weight gain can be attributed to many factors, such as excessive food intake, sedentary lifestyle, socioeconomic deprivation, medications, depression, genetic and endocrine disorders (Whitehead and Bano, 2019). Several hormonal imbalances affect obesity, including ghrelin—which is produced in the fundus of the stomach—androgens and oestrogens. Ghrelin levels increase before eating a meal, leading to hunger. After eating, ghrelin levels reduce, which leads to satiety (feeling satisfied). Women with PCOS have low levels of ghrelin that are not affected by eating, therefore causing reduced satiety, which results in increased food consumption and weight gain. Androgens increase visceral fat (fat around the organs) and oestrogen is responsible for subcutaneous fat distribution, mostly on the hips (Whitehead and Bano, 2019).
Obesity and fertility
In maternity services, many women struggle with fertility for various reasons. Fertility can commonly be affected by obesity, and symptoms of PCOS can be improved with weight loss. Currently, women pursuing fertility treatment in the NHS are only eligible with a BMI 30 kg/m2 or less, or a BMI 35 kg/m2 or less if they choose private healthcare. Given this, many women who desperately want to have children may resort to weight loss interventions in an effort to lose weight quickly, particularly as age is also a factor associated with infertility (NHS, 2019).
Risks of obesity in pregnancy
Almost 1 in 5 (20%) pregnant women have a BMI of 30 kg/m2 or above at the beginning of their pregnancy (Denison et al, 2018). Women with obesity have an increased risk of miscarriage, hypertension, gestational diabetes, pre-eclampsia and caesarean delivery, compared with women of a normal weight (BMI 18.5–24.9 kg/m2). Caesarean sections have associated risks such as infection, bleeding and other complications that are greater and more complex for a woman with obesity. Babies born to obese mothers have an increased risk of birth defects, such as heart and neural tube defects; low birth weights and macrosomia. Losing weight before pregnancy therefore reduces these risks to mother and baby (American College of Obstetricians and Gynaecologists, 2009). To achieve and sustain weight loss, people must modify their eating behaviours, increase their exercise and understand why they have struggled with their weight; commonly this is associated with emotions, boredom and trauma, and may require psychological support (Moskovich et al, 2011).
In England, the NHS recommends that weight loss is initially supported in the community with lifestyle interventions. If the patient meets the NICE (2014) criteria (Box 1), the local clinical commissioning group is responsible for agreeing funding and a GP can refer the patient to a specialist obesity weight management service delivered by a multidisciplinary team.
After engagement with these services, the surgical multidisciplinary team may consider the patient for bariatric (weight loss) surgery. Bariatric surgery is recommended as a cost-effective, evidenced-based intervention to reduce weight and associated co-morbidities in people with severe obesity (Gloy et al, 2013; Chang et al, 2014).
A variety of surgical interventions are available, although successful weight loss after any surgery relies on changing lifestyles including eating behaviours, exercise and mental wellbeing. It is also recommended that women do not become pregnant for 12–18 months after bariatric surgery to ensure the stabilisation of maternal nutrition for the safe development of the fetus (Mechanick et al, 2013). If pregnancy occurs before this recommended time frame, close surveillance of maternal weight, nutritional status and ultrasound monitoring of fetal growth should be considered.
Over the past 10 years, surgical interventions in the UK have been more widely accessible (NICE, 2014); therefore, midwives may have women who have undergone bariatric surgery in their caseload. Midwives should have an understanding of their specific care requirements in order to provide appropriate individualised care (Nursing and Midwifery Council (NMC), 2018).
Common bariatric surgical procedures
There are several surgical procedures (Figure 1) that are commonly used to assist in weight loss. These procedures, which are mainly performed laparoscopically, use mechanisms such as reducing food intake, altering signals (nerve and hormonal) from the gut, and reducing the stomach size, digestion and absorption. A decade ago, the insertion of the adjustable gastric band was a common procedure both in the NHS and private healthcare. More recently, however, gastric band insertions are declining and account for approximately 10% of operations in the UK (British Obesity and Metabolic Surgery Society (BOMSS), 2018). The National Bariatric Surgery Registry data for 2015-17 reported that Roux-en-Y gastric bypass surgery is now the most common in the UK (45%), followed by a sleeve gastrectomy (36%) (BOMSS, 2018).
Adjustable gastric band
In this procedure, an inflatable gastric band is placed around the top of the stomach, creating a small pouch. The passage of food through the band stimulates the vagus nerve, which signals the brain to increase feelings of satiety after eating. The band can be adjusted with saline to optimise the feelings of satisfaction. Initial post-operative complications of the gastric band are low; however, in the long term, a high percentage of patients require removal due to intolerance, slippage, band erosions, port site infections and reflux. Excessive or persistent vomiting can lead to potential nutritional deficiencies and slippage of the gastric band.
Sleeve gastrectomy
A sleeve gastrectomy involves removing approximately 80% of the stomach, restricting the volume of food consumed. Additionally, a high percentage of the ghrelin hormone, which is produced in the fundus of the stomach and suppresses appetite and hunger, is also removed. Initially, post-operative complications can occur, including leaks, ulcers and strictures. Long-term reflux is also common. Vomiting and eating in the early stages can lead to staple line leaks, whereas vomiting later may be associated to strictures, oesophageal dysmotility and over-eating.
Gastric bypass
There are various types of gastric bypass operations being performed such as the one anastomosis gastric bypass (the mini bypass) but the Roux-en-Y gastric bypass remains the most common and has more long-term data. The Roux-en-Y gastric bypass creates a smaller stomach (25–30 mls) and re-routes the passage of gastric contents bypassing the stomach and proximal small bowel. This re-routing speeds up the transit of gastric contents, reducing absorption. As a result, nutritional supplementation is required for life after this procedure, in order to prevent deficiencies in thiamine, iron and vitamin B12.
Considerations for antenatal care after bariatric surgery
Adjustable gastric band
Women who have undergone an adjustable gastric band insertion are required to be monitored for symptoms such as difficulty swallowing, vomiting, reflux, recurrent chest infections and night coughs. However, it is important to differentiate whether these symptoms are related to pregnancy or the gastric band. These symptoms are commonly related to a tight or slipped gastric band, meaning that deflation should be considered and the bariatric surgical team consulted. Deflating the gastric band should resolve these symptoms; however, if they continue, a slipped gastric band should be considered an emergency. A slipped gastric band can be identified using radiology intervention or oesophago-gastro-duodenoscopy (OGD); the choice dependent on the trimester of the woman's pregnancy and severity of symptoms. If a slipped gastric band is identified, the bariatric surgeon will remove the gastric band as an emergency procedure under general anaesthetic. Hyperemesis increases the risk of complications and therefore women with a gastric band should be managed on an individual basis during pregnancy (Denison et al, 2018).
Gastric bypass and sleeve gastrectomy
Women who have undergone a gastric bypass or sleeve gastrectomy surgery may experience common pregnancy-related problems such as nausea, vomiting, and abdominal pain; however, these symptoms can also mimic post-operative bariatric and gastrointestinal complications. Symptoms therefore require assessment and investigation by the bariatric surgical team to determine whether they are related to the surgery, and are a result of an internal hernia (in the case of a gastric bypass), reflux, aspiration or strictures.
Dumping syndrome can occur after eating sugars, high-glycaemic carbohydrates and fats. It is more common after a gastric bypass but sometimes occurs following a sleeve gastrectomy. Symptoms include abdominal cramping, bloating, nausea, vomiting, and diarrhoea. Increased levels of insulin and hypoglycaemia can occur later, resulting in tachycardia, palpitations, anxiety, and sweating.
Women who have had a gastric bypass and sleeve gastrectomy surgery are also at risk of malabsorption of oral medication due to a reduction in gastric acid. Therefore, slow- or modified-release preparations are not recommended and oral solutions or rapid-release preparations are preferred. Alternative preparations may therefore need to be considered and a medication review with the doctor is recommended. It is also imperative to monitor renal function before prescribing medications, especially if the pregnant woman reports vomiting. When prescribing medications, it is good practice to collaborate with the pharmacist.
The management of symptoms is crucial for women who have had bariatric surgery. To assist midwives in managing women safely and effectively, Table 1 lists common symptoms, potential causes and problems, and the recommended action required.
| Symptoms | Potential cause/problem | Action |
|---|---|---|
| Total dysphagia: difficulty swallowing saliva, vomiting (gastric band) | Acute band slippage (herniation): emergency assessment even if woman is well | Urgent referral for band deflation and potential surgery |
| Gastrointestinal bleed: vomiting blood, pain, tachycardia, hypotension | Anastomotic bleed, potential ulcer | Urgent referral to surgical team/A&E for band deflation, OGD, CT scan |
| Intestinal obstruction: vomiting, pain | Anastomotic stricture, internal hernia or port site hernia | Urgent referral to surgical team/A&E, CT scan |
| Chest pain, tachycardia, breathlessness | Pulmonary embolus, myocardial infarction, gastric pouch problems, anastomotic leak | CT scan, urgent referral to surgical team/A&E |
| Abdominal pain | Potential obstruction from internal hernia, anastomotic leak, constipation, biliary colic | Referral to surgical team/A&E, CT scan, OGD, ultrasound scan |
| Reflux, no dysphagia of fluids | Band slip, gastrojejunal stenosis, oesophageal dysmotility, hiatus hernia | Refer to bariatric surgical team, OGD |
| Port site infection (gastric band) | Gastric band erosion, infected band, leaking band | Refer to bariatric surgical team |
| Constipation | Pre-operative liver shrinking diet; Post-operative diet (both diets lack fibre) | Laxatives, linseed, vegetables, exercise depending on pre- or post-operative stage |
| Diarrhoea | Dumping syndrome | Reduce carbohydrate and fat in diet increase protein and vegetables |
| Hair loss/thinning | Lack of protein, selenium, zinc | 60–80 g protein (reduced if renal failure). Good quality multivitamin |
Source: Monkhouse et al (2014). OGD: oesophago-gastro-duodenoscopy
Nutritional status monitoring, multivitamins and blood tests
Nutrient deficiencies can also occur in women who have undergone bariatric surgery, as a result of decreased food intake or food intolerances. Pregnancy can aggravate nutritional deficiencies; however, women who have undergone a gastric bypass are at a high risk of deficiencies in micronutrients such as vitamin B12, iron, folate and fat-soluble vitamins. Women with previous bariatric surgery should have nutritional surveillance and screening for deficiencies during pregnancy. Protein, iron, folate, calcium, and vitamins B12 and D are the most common nutrient deficiencies after gastric bypass surgery and sometimes following sleeve gastrectomy. For pregnant women who have had bariatric surgery, screening for micronutrient deficiencies should be considered at the beginning of pregnancy and deficiencies should be treated accordingly. A complete blood screen including iron, ferritin, calcium, and vitamin D levels are recommended every trimester (Denison et al, 2018).
Women who are planning a pregnancy after bariatric surgery are recommended to take 5 mg folic acid before conception until the 12th week of pregnancy to reduce the risk of neural tube defects (O'Kane et al, 2014). Women are also advised to take multivitamin and mineral supplements. Women who have had a gastric bypass may require vitamin A in the beta carotene form but should avoid vitamin and mineral supplementation that contains vitamin A in the retinol form during the first 12 weeks of pregnancy (O'Kane et al, 2014). For women who have had a gastric bypass, fat soluble vitamins such as A, D, E and K should be monitored due to the limited intake and absorption of fat. Table 2 indicates the nutritional supplements recommended by BOMSS.
| Nutritional supplement | Gastric bypass | Sleeve gastrectomy | Gastric band |
|---|---|---|---|
| Can affect the absorption of Iron, vitamin B12, calcium and vitamin D | Can affect the absorption of Iron, vitamin B12 | If too tight a gastric band this may affect quality of diet: protein and Iron | |
| Multi-vitamin | Yes | Yes | Yes |
| Iron | Yes | Yes | Yes |
| Folate 5 mg | Yes | Yes | Yes |
| Vitamin B12 | Yes | Yes | Multivitamin |
| Calcium and vitamin D | Yes | Yes | Multivitamin |
| Selenium | Multivitamin | Multivitamin | Multivitamin |
| Zinc and copper | Multivitamin | Multivitamin | Multivitamin |
Source: O'Kane et al (2014)
Hyperemesis in pregnancy
Prolonged vomiting in pregnancy, such as hyperemesis, can lead to severe thiamine deficiency. It is also advisable to assess vitamin B12 and copper levels, and any deficiencies should be corrected (O'Kane et al, 2014). Occasional regurgitation or vomiting of food after bariatric surgery is not uncommon; however, prolonged vomiting is not normal and women should be referred back to the bariatric surgical team for further investigation, especially if it is not considered pregnancy-related (Monkhouse et al, 2014). For women with gastric bands, severe vomiting can cause the gastric band to slip, which requires urgent management.
Venous thromboembolism
Women with a BMI 30 kg/m2 or greater pre-pregnancy or at booking are at risk of developing venous thromboembolism during pregnancy and the guidance from the Royal College of Obstetricians and Gynaecologists (RCOG) (2015a; b) should be followed.
Contraception after bariatric surgery
It is recommended that pregnancy is delayed for 12–18 months after bariatric surgery, due to the initial rapid weight loss. Rapid maternal weight loss in the months after bariatric surgery increases fertility, but risks to the fetus from rapid weight loss remain high (Saber et al, 2008). Sleeve gastrectomy, gastric bypass operations and vomiting can affect the absorption of oral medications including contraceptive medication; therefore, a change in contraceptive medication or using additional precautions is recommended (Graham et al, 2014; Schlatter, 2017).
The levonorgestrel-releasing intrauterine device (IUD) has a safe profile (Hillman et al, 2011), and hormonal IUDs are highly efficacious, with lower pregnancy rates than the copper IUDs (Heinemann et al, 2015). However, IUDs can be difficult to insert and tolerate, with reported side effects such as dysmenorrhea, pain, device expulsion, pelvic inflammatory disease and infection (Steenland, 2013; Rowe et al, 2016).
Conclusion
Pregnant women who have had bariatric surgery should be regarded as high-risk and should receive care from the multidisciplinary team (including, when appropriate, the bariatric surgical team), with the midwife co-ordinating the plan of care (NMC, 2018). Midwives have a responsibility to ensure that women who have had bariatric surgery have a robust clinical assessment, including symptoms of vomiting and abdominal pain, nutritional status and deficiencies. Communication between the local bariatric surgical team and bariatric dietitian is recommended—especially if women present with symptoms of excessive vomiting or pain—to assess whether their symptoms are pregnancy-related or whether pregnancy is masking issues as a result of bariatric surgery.