Deflation of the band during pregnancy afects maternal and fetal weight gain. Pilone and coworkers (2014) studied 22 pregnancies after band placement and reported that all women underwent full delation of the band in the first trimester and gained an average of 14.7 kg during pregnancy. In another study, 42 women underwent deflation of the band, whereas 54 women maintained band inlation. A deflated band was associated with higher mean weight gain-15.4 kg versus 7.6 kg, increased birthweight-3712 versus 3380 g, and a twofold greater risk of macrosomia compared with an inflated one (Cornthwaite, 2015). Rarely, the band may slip from nausea and vomiting, especially with advancing gestation or postpartum (Pilone, 2014; Schmitt, 2016; Sufee, 2012). One fatal fetal cerebral hemorrhage developed from maternal vitamin K deiciency secondary to prolonged vomiting due to band slippage that created a gastric outlet obstruction (Van lieghem, 2008).
The laparoscopically performed Roux-en-Y gastric bypass is the most commonly used procedure for gastric restriction and selective malabsorption. Its surgical steps are described in
Figure 48-9.
As with other bariatric procedures, pregnancy outcomes are changed remarkably following Roux-en-Y bypass (Adams, 2015). As shown in Table 48-3, rates of hypertension, gestational diabetes, and fetal macrosomia are reduced. Serious complications are uncommon, however, upper abdominal pain is frequent in pregnancy and often associated with internal
FIGURE 48-9 Roux-en-Y bypass. With this, the proximal stomach is completely transected to leave a 30-mL pouch. The proximal end of the distal jejunum is then connected to the small pouch. This bypasses a large part of the stomach and duodenum. At a site 60 cm distal to this gastrojejunostomy, a Roux-en-Y enteroenterostomy is also completed to allow drainage of secretions from the unused stomach and duodenum.
herniation, which is protrusion of the bowel through a mesentery defect. Petersen and associates (2017) described outcomes in a birth cohort including 139 pregnancies. Upper abdominal pain complicated 46 percent, and a third of these had internal herniation. The preterm birth rate was 14 of 64 among those with upper abdominal pain versus 1 of75 in those without pain. Intussusception and small bowel obstruction can develop from internal herniation, and maternal deaths from herniation and obstruction have been reported (Moore, 2004; Renault, 2012). Bowel obstruction is notoriously diicult to diagnose (Vannevel, 2016; Wx, 2013).
Because of its associated health successes, bariatric surgery is popular, and many women subsequently become pregnant (Narayanan, 2016). From observational studies, fertility rates improve and obstetrical complication rates decline in women after bariatric surgery compared with morbidly obese controls (Kominiarek, 2017; Yi, 2015). In one these studies, despite surgical treatment, almost half of 670 women were still obese at the time of their first pregnancy after bypass Qohansson, 2015). Nevertheless, the frequency of large-for-gestational-age newborns dropped from 22 to 8.6 percent and of small-forgestational-age neonates rose from 7.6 to 15.6 percent. In a systematic review, Yi and colleagues (2015) conirmed these fetal weight trends after bariatric surgery. Also, risks for diabetes and preeclampsia were reduced.