Obesity and gynaecological practice

Obesity impacts a wide variety of situations in gynaecological prac­tice. As discussed previously, obese adolescent girls are at risk of premature menarche and physical maturity in comparison to lean counterparts.

Menstrual disorders

Obesity in adolescents is also associated with menstrual irregular­ities. Although obese adult women often present with menstrual ir­regularities, there is limited data describing the association between obesity and heavy menstrual bleeding (93).

Although obese women often present with menstrual disorders, such as oligomenorrhoea or amenorrhoea, there are limited data on the link between obesity and heavy menstrual bleeding (94). The prevalence of menstrual cycle irregularities was 8.4% in women who were 74% overweight compared to 2.6% in women who were less than 20% overweight. It has also been reported that the relative risk of oligomenorhoea in women with upper body fat predominance was 3.15 compared with lower body fat predom­inance (93). The investigation and treatment protocols should be the same as for women with normal weight but particular focus is required to rule out endometrial hyperplasia in obese women. The risk of developing endometrial cancer in women with PCO is three times higher than in women with a normal BMI. The med­ical treatment of menstrual disorders for obese women is similar to normal-weight women, their therapeutic effectiveness and ad­verse outcomes require careful consideration in the former group. It is known that BMI does not affect the efficacy of the combined oral contraceptive pill and therefore, the use of the combined oral contraceptive pill remains a viable option in this group of women with BMI of up to 35 (93).

Polycystic ovarian syndrome

PCOS is common in obese women but not all women with PCOS are obese. Obesity may enhance the biochemical and hormonal changes observed in women with PCOS and this in turn has ad­verse effects on reproductive outcomes in these women (95, 96). The severity of hyperandrogenism seems to be amplified in obese women with PCOS and ovarian hyperandrogenism may arrest the development of antral follicles. Adipocyte conversion of androgens to oestrogens with consequent reduction in sex hormone-binding globulin disrupts the delicate milieu required for folliculogenesis. Obese women with PCOS exhibit a higher degree of insulin resist­ance and hyperinsulinaemia. It has been shown that insulin infusion decreases basal and gonadotropin-releasing hormone-induced lu­teinizing hormone (LH) secretion. Several substances produced by the adipose tissue including leptin, adiponectin, resistin, and visfatin may play a role in the pathophysiology of PCOS. Leptin plays an important role, as an inverse relationship between leptin and LH levels and LH pulse amplitude has been reported. When there is a short-term caloric restriction, leptin levels decline and there is an increase in LH pulse amplitude. Obesity also changes inflammatory markers (C-reactive protein, interleukin-6, and tumour necrosis factor alpha), coagulation, and fibrinolysis mechanisms (97). These aberrant changes may therefore interfere with the reproductive cycle to cause deleterious outcomes. Diet and lifestyle changes are recom­mended for the obese women before they attempt conception. For induction of ovulation, clomiphene citrate remains the first line therapy.

Infertility

Infertility and reduced fecundity is demonstrated in obese women. Obesity in women is associated with anovulatory subfertility, al­tered oocyte quality, and endometrial receptivity (97). All modes of conception (natural, ovulation induction, in vitro fertilization, intracytoplasmic sperm injection, and ovum donation) in obese women are associated with poorer reproductive outcomes. The probability of conceiving naturally within one menstrual cycle is re­duced by 18% in obese women compared to women with a normal BMI after adjusting for age, smoking, and race (98). Furthermore, in subfertile ovulatory women, each single-digit increase in BMI over 29 kg/m² was associated with an approximately 5% reduction in pregnancy rate comparable to a 1-year increase in female age- associated reduction in pregnancy rate.

Methods of assisted reproductive technology fare no better. When compared between obese and normal-weight young ((101). Increasingly, BMI seems to have a direct effect on the severity of pelvic floor dysfunction by a chronic increase in intra-abdominal pressure, damage to pelvic musculature, nerve damage, and asso­ciated conduction abnormalities. Obesity-related comorbidities such as diabetic neuropathy and intervertebral disc herniation may also be contributory factors. Significant weight loss by surgical or non-surgical means leads to improvement in symptoms of incon­tinence. Stress incontinence surgery in obese women is equally ef­fective as in normal-weight women. Unfortunately weight loss has not been shown to reverse the severity of symptoms due to pelvic organ prolapse. Weight loss may, however, alleviate the postsurgical morbidity associated with obesity and prolapse surgery. Faecal in­continence improves after surgical-induced weight loss. Therefore, the first line of management for such women in primary care set­tings should focus on lifestyle changes, weight management, and physiotherapy (102).

Post-reproductive symptoms

Western women now spend more than a third of their lifetime be­yond the menopausal transition. Research has explored the impact of obesity on the timing of menopause and the effect of obesity on menopausal symptoms and reproductive hormones (103). It has shown no significant impact of obesity on the timing of menopause and the levels of oestrogens and follicle-stimulating hormone as compared with non-obese women. These studies did not identify why obese women suffer from exaggerated vasomotor symptoms. Vulvovaginal atrophy with its symptoms of vaginal dryness, itching, dyspareunia, and irritation is strongly and consistently linked to oestrogen deficiency and is highly prevalent in menopausal and perimenopausal women. Weight gain reported around the transi­tion of menopause is mainly due to lack of activity rather than hor­monal changes.

Risk of developing cancers

It has been estimated that obesity is associated with approximately 20% of cancers (104) and a 15-30% decrease in weight is associ­ated with a reduced risk of cancer (105). Obesity increases the risk of endometrial cancer, oestrogen receptor-positive postmenopausal breast cancer, and, to a lesser extent, ovarian cancer. It is postulated that oestrogens, sex hormones, hyperinsulinaemia, adipokines, and inflammatory cytokines among other factors may be involved in the promotion of cancer in obese women. Although a high risk of cancer recurrence among obese women has been reported, it is most likely due to suboptimal treatment and/or comorbidities. Equally, adjuvant chemotherapy and radiation dosimetry in breast and ovarian cancer patients may be less effective in obese women. A meta-analysis of observational studies published in 2015 has also reported a strong association between type 2 diabetes mellitus and the risk of breast, intrahepatic cholangiocarcinoma, colorectal, and endometrial cancers (106).

Another meta-analysis from 2014 has shown an increased risk of endometrial cancer in overweight and obese women (107).

Role of bariatric surgery in obese women

Developments in minimal access surgical techniques are now al­lowing an increasing number of more complex gynaecological pro­cedures to be undertaken for women with complex comorbidities and obesity laparoscopically. This is largely to minimize difficulties confronted with open surgery in obese women.

Anaesthetic issues

Cardiac and respiratory responses are often altered in patients with an increased BMI, and they are predisposed to decreased functional reserve capacity (42, 109). Cardiorespiratory functions are further compromised with Trendelenburg positioning and raised intra­abdominal pressure following the creation of a pneumoperitoneum. Obesity also affects gastric functioning with delayed emptying time. These women are also at an increased risk of infection sec­ondary to impaired immune surveillance. Prolonged surgery (> 4 hours) increases the risk to obese patients. Technical issues should be considered in order to reduce visceral and vascular injuries. The cumulative experience globally with the minimal-access approach to treat benign pelvic pathology and selected cases of gynaecological cancers for obese women has not reported higher complication rates compared to their non-obese counterparts, despite having pro­longed operating time. Potential advantages include shortened hos­pital stay with shorter recovery time and lower infection rates.

Weight management

The best way to reduce the risk of medical and obstetric complica­tions in obese women is for weight loss to occur prior to conception. There is limited maintained weight loss with dieting, exercise, be­havioural therapy, and medical therapy. The average weight loss at 1 year is approximately 5 kg (110).

There are three main surgical approaches: restrictive, malab sorptive, and combined procedures. Restrictive procedures include gastric bands and sleeves whereas malabsorptive methods include biliopancreatic diversion and duodenal switch. The most commonly used procedure is the Roux en Y gastric bypass which is a combined restrictive and malabsorptive method. It involves bypassing the duodenum by creating a small gastric pouch and gastroenterostomy stoma.

Bariatric surgery has been shown to improve hormonal levels in obese women wishing to conceive. There are conflicting data on miscarriage rates following surgery. There is no difference after biliopancreatic diversion but restrictive procedures are associated with high rates of miscarriage despite weight loss (113). However there are improved maternal and neonatal outcomes in obese women who have had bariatric surgery. There is a reduction in the incidence of pregnancy-induced hypertension and pre-eclampsia but not al­ways gestational diabetes (44, 113). There is a significant reduction in the number of large-for-gestational-age infants. Women who have had malabsorptive and combined bariatric procedures are at an increased risk of fetal growth restriction and prematurity compared with women who have had restrictive procedures.

It is recommended that women who have had bariatric surgery should delay conception and the American College of Obstetricians and Gynaecologists suggests a delay of approximately 12- 24 months. The impact of pregnancy on the prior weight loss surgery can be dramatic. Band migration can lead to vomiting, dehydration, and band leakage. There is also a risk of intestinal obstruction secondary to adhesions, intestinal hernia, gastric ulcer, and strictures in the staple line. These are associated with a requirement for surgical intervention.