Part of “CHAPTER 110 – ENDOCRINE DISEASE IN PREGNANCY“

Obese individuals are at increased risk for hypertension, diabetes mellitus, hypertriglyceridemia, and coronary artery disease, all of which may affect the health of a pregnant woman (see Chap. 126). Operative wound infections and dehiscence, and postoperative thromboembolic disease also are more common among these patients.

In patients with morbid obesity (>100 lb overweight or >200% of ideal body weight), respiratory impairment, which may be a major source of morbidity, takes three forms. The first is directly related to increased chest wall and abdominal fat, and consists of a reduction in lung and chest wall compliance. In an ambulatory setting, these patients do not retain carbon dioxide, but they may be slightly hypoxic, especially when supine.143 After abdominal surgery, such as a cesarean section, massively obese patients have a further reduction in arterial partial pressure of oxygen (PaO₂), with the nadir appearing on the second postoperative day.143 A much smaller group of massively obese patients have hypoventilation, hypercapnia, hypoxia, somnolence, and markedly reduced lung compliance—a constellation of findings that has been referred to as the pickwickian syndrome. Finally, some patients with obesity develop upper airway obstruction when asleep (or sedated) and have hypoxia and even apnea.

These concerns have important implications for obese women who become pregnant. Several series reporting data in such women have been published. In women in the top fifth percentile for weight (>90 kg at term), the incidence of hypertension and gestational diabetes was increased two- to eightfold.144,145 and 146 Slight increases also were noted in the rates of other complications, including thrombophlebitis, preeclampsia, urinary tract infection, and infection of an episiotomy or other wound.144,145 and 146 Although an increased rate of respiratory complications related to the influence of the expanding uterine contents on an already impaired respiratory apparatus would be expected, this was not found in these series.144,145 and 146 The rate of cesarean section was increased in these women in one series,146 but not in the other two.144,145 Thus, obese women should be screened periodically for gestational diabetes and monitored carefully for the development of hypertension, urinary tract infection, and preeclampsia. For obese women with complicated deliveries who may remain at bed rest for extended periods, prophylactic subcutaneous heparin may be indicated. In massively obese women, care also must be taken to prevent respiratory compromise.