Category 1
Method can be used without restriction
Category 2
Benefit outweighs the theoretical or proven risk
Category 3
Theoretical or proven risk outweighs the benefit
Category 4
Unacceptable health risk
Common Contraceptive Concerns in Obese Women
Effectiveness is one of the most important characteristics for women when choosing a contraceptive method [8]. Effectiveness of hormonal contraception may be impacted by metabolic differences in women of differing weights [9, 10]. Until recently, the majority of pharmacokinetic data excluded overweight and obese women. Recent studies indicate there may be differences in the metabolism between normal and overweight women [11–14], but data from clinical research studies has not shown increased method failure rates [15, 16].
A second common concern in this population is increased risk of venous thromboembolism (VTE) with estrogen-containing contraceptives given the increased incidence of VTE in obese populations [17]. Given VTE is a rare event in the reproductive-age population, there is limited data investigating whether obese patients have an increased risk when using combined hormonal methods. Current expert opinion allows the use of estrogen-containing methods in obese women if no other contraindications exist (e.g., personal history of VTE, hypertension, or cardiovascular disease).
Lastly, many obese women have medical comorbidities such as diabetes or hypertension and clinicians are faced with navigating complex medical histories to counsel women on safe and effective contraceptive methods. Most medical comorbidities affect eligibility for estrogen-containing contraception. Nonhormonal and progestin-only methods remain safe for women with most medical comorbidities. We encourage healthcare providers to use the US MEC to maneuver these individual patient characteristics.
Long-Acting Reversible Contraceptives
There are currently four LARC methods available in the United States, three intrauterine devices (IUDs) and one subdermal implant. LARC methods are the most effective reversible methods with failure rates less than 1 % [18]. They have very few contraindications and are particularly well-suited for the overweight and obese population as none of these methods contain estrogen (MEC 1). LARC methods do require a clinician visit for insertion and removal, which may be interpreted as an access barrier. However, it also provides clinicians with an opportunity to provide counseling related to the woman’s obesity-related health risks.
Intrauterine Devices
There are currently two well-studied IUDs available in the United States: the 52 mg levonorgestrel intrauterine system (LNG-IUS) and the copper T380 intrauterine device (Cu-IUD) (Fig. 9.1). The LNG-IUS is currently FDA-approved for up to 5 years of use. The T-shaped frame contains 52 mg of the progestin levonorgestrel. There are several mechanisms by which pregnancy is prevented; cervical mucus thickening, inhibition of sperm motility and capacitation, and thinning of the endometrial lining [18]. The LNG-IUS also has several non-contraceptive benefits. Average monthly blood loss decreases significantly and up to 20–40 % of women will become amenorrheic after 1 year of use [19–21]. This may be of particular benefit to women who experience difficulty with menstrual hygiene as a result of severe obesity. The rate of amenorrhea may be influenced by BMI; one study found that women with higher BMI had a delay to amenorrhea, but 25–72 % achieved amenorrhea between the fourth and fifth year of use [22]. Regardless of whether amenorrhea is achieved, the LNG-IUS offers protection against endometrial hyperplasia and adenocarcinoma, an important benefit in this population who are exposed to excess circulating estrogens. The LNG-IUS has been investigated as a nonsurgical treatment for endometrial hyperplasia and malignancy [23–25] and is frequently considered in obese women who have comorbidities that make them poor surgical candidates or where future fertility is desired [26, 27].
Fig. 9.1
Long-acting reversible contraceptive methods. (a) 52 mg LNG- IUS (b) Cu-IUD (c) ENG implant
The Cu-IUD is a nonhormonal method in which the T-shaped frame is wrapped in copper wire. This method is currently FDA-approved for up to 10 years of use making it one of the most cost-effective reversible methods available [28]. Pregnancy is prevented mainly through the spermicidal action of the copper ions [29]. Because the Cu-IUD does not deliver any hormone to the endometrium, it does not improve the bleeding profile of users. Despite the lack of hormone, it has been shown to also provide protection against endometrial hyperplasia and adenocarcinoma, likely as a result of the endometrial inflammatory process [24].
A third IUD, the 13.5 mg LNG-IUS, has recently been approved by the FDA for up to 3 years of use. There is limited data about the use of this method in overweight and obese women. Due to a lower dose of levonorgestrel, the rate of amenorrhea was dramatically lower (12 % vs. 40 %) in the studied population (<130 % ideal body weight). Given that the rate of amenorrhea may be lower in obese women with the 52 mg LNG-IUS, the 13.5 mg is even less likely to result in amenorrhea. Similarly, there is currently no data evaluating the extent to which this device provides endometrial protection against hyperplasia and adenocarcinoma.
Like all contraceptive methods, there are risks to IUD use. Spontaneous expulsion occurs in 2–10 % of users [30, 31]. There is no data to suggest that this rate is higher in obese women. Obese women who expel their IUD should be managed in the same manner as normal-weight women. Uterine perforation at the time of insertion is low, estimated at less than 1/1,000 insertions [32]. The risk of perforation is correlated to clinician experience and is lower in more experienced clinicians [32]. There is no data that indicates perforation rates are related to body weight, although clinicians may perceive insertions to be more difficult in obese women. If perforation is recognized at the time of insertion, the device can be easily removed. However, if perforation is unrecognized at the time of insertion and the IUD is found to be intra-abdominal, removal of the IUD may be challenging in the obese patient. The standard recommendation for an extrauterine IUD is laparoscopic removal. In an obese or morbidly obese woman, laparoscopic removal may be technically difficult. In such an instance, some clinicians have chosen to leave the LNG-IUS in situ [33, 34]. Because the Cu-IUD acts primarily through an inflammatory response, careful consideration of surgical risk should be completed before deciding to leave the IUD in the abdomen. One small study compared intraoperative laparoscopic findings in women who were undergoing removal of intra-abdominal IUDs and found no difference in adhesion formation between the two devices [35]. However, these results should be interpreted with caution as the time since insertion was relatively short ranging from days to 7 months. Given that perforation is rare, there is no evidence regarding the contraceptive efficacy of intra-abdominal LNG-IUS, therefore another form of effective contraception should be initiated.
Subdermal Implant
The subdermal etonogestrel implant is a single ethylene vinyl acetate rod measuring 4 cm in length that continuously releases the progestin etonogestrel (ENG) (Fig. 9.1). The continuous release of ENG suppresses ovulation, inhibits endometrial proliferation, and thickens cervical mucus [18, 36]. Results of pharmacokinetic studies of the implant in overweight and obese women suggest that this population has a lower serum concentration of ENG [11, 37]. However, the levels remain well above the level required for ovulation suppression. The significance of this finding is unknown given the small sample size. A large observational study revealed no increase in the rate of unintended pregnancy in overweight and obese implant users [16]. Furthermore, a study evaluating serum ENG levels in overweight and obese women at the end of three and four years of implant use found that ENG levels were similar in obese and normal-weight women, and that those levels remained above the threshold for ovulation supression [38].
Unlike IUDs, initiation of the implant does not require a pelvic exam. The device is placed superficially under the skin of the arm after administration of local anesthesia. The major disadvantage of the implant is unpredictable irregular bleeding. Bleeding patterns can range from amenorrhea to daily spotting. Obese women may be less bothered by the irregular bleedings as obese women have a higher incidence of irregular bleeding than normal-weight women. Several potential interventions have been suggested to address the irregular bleeding patterns [39], but there is limited evidence to suggest that any of these interventions are effective.
User-Dependent Methods
Methods that require continued action from the user are termed user–dependent methods. These include injectables, the vaginal ring, the contraceptive patch, and oral contraceptive pills.
Depot Medroxyprogesterone Acetate
DMPA is an injectable progestin that is administered every 11–13 weeks. It prevents pregnancy primarily by ovulation suppression [40], and secondarily through thickening of the cervical mucus and endometrial alterations [41–43]. Typical-use failure rates range between 2 and 6 % [18, 44]. While one study found lower levels of medroxyprogesterone acetate in obese women, these levels were still considered sufficient and there is no evidence to suggest there is an increased risk of failure in obese DMPA users [13, 45].
The absence of estrogen is one advantage of DMPA for obese women The American College of Obstetrics and Gynecology released a bulletin stating that DMPA is a safe method for women with known risk factors for cardiovascular disease, thromboembolism, congestive heart failure, and cerebrovascular disease [46]. Similar to the LNG-IUS, DMPA users can expect significant reduction in menstrual blood loss or complete menstrual suppression, which occurs in up to 50 % of users at 12 months [47, 48]. Like other progestin-only methods, DMPA also provides endometrial protection and has been shown to reduce the risk of endometrial cancer by as much as 80 % [49, 50].
DMPA does have several disadvantages. DMPA has been associated with weight gain, which may be a particular disadvantage for already obese women. Some studies suggest that overweight and obese women, particularly adolescents, may experience more weight gain than normal-weight users [51–53] with DMPA use. Long-term DMPA use has been associated with a temporary and usually reversible decrease in bone density [54–57]. The combined evidence on weight gain and bone loss support the current MEC category 2 for women with BMI >30 and less than 18 years old. For women greater than 18 years, the recommendation remains category 1.
Combined Hormonal Contraceptives
Combined hormonal contraceptives (CHC), which contain both estrogen and progestin, are among the most commonly-used reversible methods in the United States [58]. CHC include the vaginal ring, transdermal patch, and combined oral contraceptive pills (COCs). All of these methods work primarily by ovulation suppression and secondarily by cervical mucus thickening. The type and amount of progestin does vary between different formulations. Concerns about effectiveness in the obese women are not unfounded. Several pharmacokinetic studies in COC users have found that hormonal half-life, time to steady state, drug clearance, and peak hormone levels may be different in obese women compared to normal-weight women [59, 60]. Despite potential differences, obese women in these studies were not found to be at any increased risk of ovulation [59, 61]. Studies of transdermal patch users found serum hormone levels to be correlated with body weight and limited evidence suggests that women weighing more than 90 kg are at increased risk of failure and pregnancy [62]. Although these studies were limited by small samples of obese women, 5 of the 15 documented pregnancies were in women over 90 kg. These women accounted for only 3 % of the study population, but represented 33 % of the pregnancies, suggesting that if these women are unwilling to consider a different method they should be counseled on a potential increase in the risk of failure. Lastly, as with COCs and the patch, the vaginal ring has been shown to have with lower serum hormone levels in obese women [14]. However, these lower levels were sufficient to reliably suppress ovulation. Obese ring users were also evaluated for prolonged use and were found to have therapeutic hormone levels even when a single ring was used for six continuous weeks [63]. Clinical outcomes data from a large observational study found that obese users of COCs, the patch, and the ring did not have an increased risk of an unintended pregnancy [15]. In summary, current data suggests that there may be pharmacokinetic differences in obese women using COCs and the ring, but that these differences do not translate into higher failure rates or increased risk of unintended pregnancy. The available data on the patch suggests that obesity is associated with a higher risk of failure and pregnancy.
Nearly all of the risks associated with CHC are related to the estrogen component, despite the fact that most of the contraceptive effect is due to the progestin. Clinicians’ concerns about using these methods in the obese women stem from the known associated comorbid conditions (e.g., hypertension, thromboembolism) that are relative or absolute contraindications to estrogen-containing methods. Nearly all CHC in the United States contain ethinyl estradiol (EE) in doses ranging from 10 to 50 mcg [18]. CHC are contraindicated in women with a personal history of thromboembolism (MEC category 4); however, use in women who are at higher risk for thromboembolism because of obesity is not contraindicated. The current MEC category for CHC use in obese women without a personal history of VTE or other contraindicated comorbid condition is 2. This categorization recognizes the elevated relative risk in obese women, which may be as high as threefold [64], but also takes into account the fact that the absolute risk is still quite small. The risk of VTE may differ by the CHC preparation. Studies comparing the transdermal patch to equivalent COCs are conflicting but suggest that there may be as much as a twofold increase in VTE among patch users [59, 65–67]. Risk of VTE in ring users has been estimated at 149 per 100,000 women, compared to 53 per 100,000 patch users [68]. Despite this elevated absolute risk, it is important to remember that the risk of thromboembolism in pregnancy and postpartum is four to five times higher than in a woman using any estrogen-containing contraceptive [69]. Therefore, the increase in VTE risk with CHC is less than the risk of VTE if she should become pregnant.
The presence of comorbid conditions in the obese population is common with hypertension and diabetes mellitus (DM) topping the list. Multiple medical problems can make contraceptive counseling difficult, but also makes pregnancy complicated and occasionally dangerous. Hypertension, even if well controlled, is category 3 for CHCs and becomes a category 4 if uncontrolled or vascular disease has been documented. CHC becomes less appropriate as the number of comorbid conditions increases. For example, insulin-dependent DM alone is category 2, however in the presence of end organ sequelae (e.g., retinopathy, neuropathy, and nephropathy) it becomes category 3 for continuing a previously initiated method and category 4 for initiating a new method. Similarly, the CDC has created a category for women “with multiple risk factors for cardiovascular disease.” Although “multiple” is not clearly defined, the category includes age, obesity, smoking, hypertension, and diabetes, many of which describe obese women. If a clinician interprets “multiple” to means 2 comorbid conditions, then any CHC method for these women would be considered category 3 for continuing a previously initiated method, and category 4 for initiating a new CHC method.
Progestin-Only Oral Contraceptives
Progestin-only pills (POP) are a safe method for obese women. Formulations of POPs in the United States are limited to norethindrone, although there are POPs containing a variety of progestins available in other countries. POPs prevent pregnancy through a combination of mechanisms including ovulation inhibition, cervical mucus thickening, and endometrial alteration, although they do not reliably suppress ovulation [18]. Typical-use failure rates in the general population mirror that of COCs, although unlike COCs, serum progestin levels are nearly undetectable 24 h following administration [70]. This finding results in the current emphasis on strict compliance of dosing at the same time every day. There are no studies specifically addressing effectiveness in the obese population, but POPs are currently categorized as category 1.
Special Populations
Increasing numbers of morbidly obese women are opting for surgical treatment of their obesity [71]. There is currently several options for bariatric procedures ranging from restrictive (gastric banding) to the traditional malabsorptive procedures (Roux-en-Y, sleeve gastrectomy, biliopancreatic diversion) [72]. Because obesity is associated with anovulation and subsequently infertility [73], many of these women may not be using effective contraception prior to their surgery as they do not consider themselves at risk for pregnancy. With rapid weight loss following surgery, these women will likely become ovulatory again; without effective contraception, they will be at risk of unintended pregnancy. The American College of Obstetricians and Gynecologist currently recommends that women delay pregnancy for 12–18 months following bariatric surgery as rapid weight loss can pose additional maternal and neonatal risk [74]. For women who have undergone a malabsorptive procedure, use of oral contraception is not generally recommended as the absorption of the steroid is likely impaired. This recommendation is based on few studies with small sample sizes [75, 76]. If women prefer oral contraceptives, consideration of nonoral routes is encouraged, for example vaginal administration [77–79]. There have been few if any studies evaluating other methods in this population. The effectiveness of the ENG implant in women who had undergone a Roux-en-Y gastric bypass was evaluated in one small study. Findings indicate that ENG levels decrease at 3 and 6 months after surgery with increasing weight loss, but remain well above the serum levels required for effectiveness [37]. There has also been one study evaluating the LNG-IUS in an adolescent bariatric surgical population and found the LNG-IUS was an acceptable and effective option in this setting [80]. Studies have shown that few women are referred for contraceptive counseling prior to their surgical intervention [81] indicating that obstetrician-gynecologists should be proactive about assessing obese patient’s desires and plans for surgical weight loss.
Permanent Sterilization
Female sterilization, also known as tubal ligation or tubal occlusion, is one of the most common methods of contraception among women in the United States with approximately 27 % relying on this method between 2006 and 2010 [82]. In overweight and obese women, surgical contraception, which includes tubal ligation, is the type of contraception most often used [83]. Tubal ligation is often a choice for women who have completed childbearing, do not wish to have user-dependent contraception, or have contraindications to hormonal forms of contraception. In addition, it is highly effective, with a cumulative 5-year failure rate of 13 per 1,000 [84]. Several options exist for sterilization and preference is influenced by timing, surgical or anesthesia risk, and technical ease.
Postpartum Tubal Ligation
Postpartum tubal ligation includes those procedures performed at the time of cesarean or immediately following vaginal delivery. The most popular techniques include the Pomeroy and Parkland methods due to their ease and effectiveness [84]. Both methods involve a complete transection of the mid-isthmic portion of the fallopian tube. The 5-year failure rate is 6 per 1,000, making postpartum tubal ligation the most effective form of sterilization [85]. Pathologic confirmation of complete tubal transection ensures immediate protection, regardless of BMI [86].
Disadvantages of postpartum tubal ligation in obese women are often related to mode of delivery. When performed at the time of cesarean delivery, the fallopian tubes are generally easily visible and accessed in the surgical field. When performed after a vaginal delivery, a separate procedure is required. Normally, this procedure is easily performed through a small infraumbilical incision where the fallopian tubes can be accessed. Some clinicians consider obese women as poor candidates for immediate postpartum sterilization after a vaginal delivery as this procedure can be technically challenging due to the increasing depth of subcutaneous tissue and difficulty accessing the tubes. In addition, even if the tubes are accessible, it may be difficult to minimize tension on the tissue, thus possibly causing laceration of the fallopian tubes, tearing of the mesosalpinx, and subsequent bleeding [84]. Due to the possibility of the latter complications, studies have been performed researching the use of titanium (Filshie®) clips for postpartum tubal ligation for easier access, but these studies have shown the titanium clip to be less effective, possibly secondary to the edema and engorgement of the tubes during pregnancy [87–89].
Interval Tubal Ligation
Interval tubal ligation includes those procedures performed before a pregnancy occurs or at any point after the postpartum period. These procedures can be performed hysteroscopically or laparoscopically.
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