Irregular Menses
Overweight adolescents often report amenorrhea, oligomenorrhea, or menometrorrhagia to their
Fig. 1.
Body mass index chart for children and adolescents. (For more information on body mass index for adolescents, visit the Centers
for Disease
Control and Prevention web site at www
12 14 16 18 20 22 24 26 28 30 32 34 BMI kg/m2 12 14 16 18 20 22 24 26 28 30 32 34 BMI kg/m2 85th 90th 95th 75th 50th 25th 10th 5th Overweight
(95th percentile and above)
At Risk of Overweight
(85th–94th percentile)
Underweight
(5th percentile and below)
Fig. 2. Body mass index for age percentiles: Girls, aged 2–20 years. (Developed by the National Center for Health Statistics in collaboration with the National Center for Chronic Disease Prevention and Health Promotion [2000].)
2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
health care providers. Being an overweight adoles- cent is associated with elevated levels of free estro- gens through increased peripheral aromatization of androgens to estrogens, decreased sex hormone binding globulin, and increased insulin levels that can stimulate ovarian stromal tissue production of androgen. The elevated peripheral estrogen levels are associated with disruption of normal ovulation and subsequent irregular menstrual cycles. Higher de- grees of overweight have been associated with high- er probabilities of menstrual cycle disturbances (19). Polycystic Ovary Syndrome
Obesity has been reported to occur in one half of adult patients with polycystic ovary syndrome (PCOS). Obesity in adult patients with PCOS is characterized by an increased waist-to-hip ratio or
android appearance as opposed to truncal obesity. The presence of obesity compounds clinical risk in adult patients with PCOS for several reasons. Obesity is associated with decreased sex hormone- binding globulin, which increases circulating free testosterone and estradiol in adults (20). Obese adults have an increased likelihood of dyslipidemia, raising concern for future cardiovascular events (21). Finally, obesity is associated with insulin resis- tance, which may progress to diabetes mellitus in adult patients with PCOS (22).
Lifestyle modification is recommended as first- line management for overweight female adolescents with PCOS. Dietary intervention studies have con- sistently demonstrated the benefit of weight reduc- tion in obese adult females with PCOS to normalize menstrual cycles and hyperandrogenism and improve metabolic variables (23).
Oral contraceptives are the standard therapy for PCOS to provide hormonal suppression of ovarian androgen production. Metformin has been approved by the U.S. Food and Drug Administration for use in patients with type 2 diabetes and is the most com- mon insulin-sensitizing agent used in studies on PCOS even though the use of metformin in these patients is currently considered off label. Some investigators state that based on current data, use of metformin can be justified in overweight adoles- cents with PCOS and insulin resistance to improve metabolic and hormonal alterations and possibly prevent long-term sequelae (24). The role of insulin- reduction therapies in treating PCOS is evolving and has substantial efficacy in restoring regularity of menstrual cycles. These therapies usually are associ- ated with initial weight loss, are less effective in the treatment of hirsutism, and may cause gastrointesti- nal side effects (25).
Table 1. Definitions
“At Risk” for
Population Becoming Overweight Overweight Obesity
Adolescent Body mass index is equal to or Body mass index greater than or Term not typically used greater than the 85th percentile equal to 95th percentile for age
for age, but less than the 95th based on growth charts by the percentile for age based on growth Centers for Disease Control charts by the Centers for Disease and Prevention
Control and Prevention
Adult Term not typically used Body mass index greater than or Body mass index greater equal to 25, but less than or equal than or equal to 30 to 29.9 Prevelance of over weight (per centage of population) 20 15 10 5 0 1971–1974 1976–1980 1988–1994 1999–2002 2003–2004
Years of NHANES study Females aged 12–19 years
Fig. 3. Overweight adolescent females aged 12–19 years. National Center for Health Statistics. Health, United States, 2005 with chartbooks on trends in the health of Americans. Hyattsville (MD): 2005. Ogden CL, Carroll MD, Curtin LR, McDowell MA, Tabak CJ, Flegal KM. Prevalence of overweight and obesity in the United States, 1999-2004. JAMA 2006;295:1549–55.
Hormonal Contraception
Recent studies suggest that women weighing more than 70.5 kg have an increased risk of unintended pregnancy while using combination oral contracep- tives compared with women who have normal body mass (relative risk 1.6) (26, 27). Another study demonstrated that women with BMIs greater than 32.2 had a higher risk of accidental pregnancy while using combination oral contraceptives than did women who have normal body mass (27). Several mechanisms have been proposed to account for the elevated failure rates in obese adult women. It has been theorized that obese adult women metabolize steroids differently than lean women possibly because of a larger blood volume to transport steroid hormones and fat cells sequestering steroid hor- mones (28). In obese adult users of combination oral contraceptives, the risk of thromboembolism is increased (29). For overweight adolescents at risk of pregnancy, it is important to balance the risks and benefits of combination oral contraceptives, includ- ing the risks from pregnancy. Consideration should be given to progestin-only oral contraceptives and intrauterine methods when counseling overweight adolescents regarding contraceptive choices. Women who weigh more than 90 kg may have a dispropor- tionately higher likelihood of contraceptive failure with the transdermal contraceptive patch (30).
Serum levonorgestrel levels are lower in obese adult women compared with nonobese adult women using a two-rod implant (not yet commercially avail- able). Yet, effective contraception is thought to last 5 years regardless of weight (31). The effectiveness of the etonogestrel single-rod implant that has been recently approved by the U.S. Food and Drug Administration for use in overweight women has not been adequately studied. However, serum concentra- tions of the synthetic progestin etonogestrel are inversely related to body weight and decrease with time after insertion. It is, therefore, possible that with time this single-rod implant may be less effective in overweight women (32). No changes in efficacy have been shown with the vaginal ring regardless of patient weight. Although injectable contraception has not been demonstrated to decrease contraceptive efficacy based on weight, it has been associated with weight gain (see Table 2).
Intrauterine Device
The effectiveness of the intrauterine device (IUD) in obese adult women is similar to that demonstrated in
adults of average weight. Insertion of an IUD can be technically challenging in the obese adult woman and often requires the use of a larger speculum for adequate visualization of the cervix. Placing a con- dom with the tip removed over the speculum blades can aid in exposure. Ultrasonography also may be a useful tool both before and during IUD insertion (33). This information may be applied to the adoles- cent population until other data are available. Pregnancy-Related Issues
Maternal obesity (BMI greater than or equal to 30) is an important obstetric risk factor independent of maternal age (34). Nearly all complications of preg- nancy, except intrauterine growth restriction, are more frequent in obese adult women (35). In a recent prospective Danish study, overweight and obese adult women had increased risks of diabetes, hypertension, preeclampsia, and cesarean delivery (36). Obesity is associated with a more than doubled risk of stillbirth (odds ratio, 2.8; 95% confidence interval [CI], 1.5–5.3) and neonatal death (odds ratio, 2.6; 95% CI, 1.2–5.8) compared with women of normal weight. Much of these data are based on adult women, but may be applied to the pregnant adolescent population until other data are available. Most adolescent pregnancies (80%) are unin- tended (37). This precludes the physician from pro- viding preconception counseling that would address diet and exercise. The goals of this counseling include avoiding specific pregnancy complications, such as macrosomia, operative deliveries, late fetal deaths, neural tube defects, gestational hyperten- sion, and gestational diabetes. There is a significant increase in cesarean deliveries in primiparous ado- lescents with BMIs greater than or equal to 30 com- pared with those with BMIs less than or equal to 20 (38). Maternal weight also has an effect on the child. Regardless of maternal age, maternal obesity in the first trimester of pregnancy is associated with elevat- ed risk of overweight in the child. Specifically, the relative risk of overweight in the child was 2.0 (95% CI, 1.7–2.3) at age 2 years, 2.3 (95% CI, 2.0–2.6) at age 3 years, and 2.3 (95% CI, 2.0–2.6) at age 4 years (39).
African-American adolescents who are over- weight before their first pregnancy become more overweight; on average, 3.3 years following the index pregnancy. They also are at increased risk of retaining gestational weight gain (40). The associa- tion between ethnicity, overweight, and obstetric and
neonatal outcomes needs further exploration in the adolescent population.
Information regarding pregnancy termination also is scarce. In second trimester dilation and evac- uation abortions, obesity has been linked with tech- nical difficulty, longer operating times, and more blood loss (41, 42).
Prevention
The American College of Obstetricians and Gyne- cologists recommends that all adolescents be screened annually for overweight by determining weight and stature, calculating a BMI for age, and asking about body image and eating patterns (43). The U.S. Preventive Services Task Force concluded that there is “insufficient evidence to recommend for or against routine screening for overweight in ado- lescents in primary care settings” (44). This is based on the lack of evidence that screening and therapeu- tic intervention improve health outcomes for over-
weight adolescents. Although ACOG recognizes the recent report and the limitations in the data, ACOG continues to support the screening of adolescents because screening and interventions may demon- strate benefit if used in combination with several modalities.
Although the research on prevention of over- weight status in adolescents has resulted in few effective recommendations, some prevention strate- gies have been generated. Parents play a significant role. A surgeon general report highlights the proba- ble protective benefit of breastfeeding in preventing overweight in children and adults (45). Health care providers should promote healthy eating and physi- cal activity to adolescent patients and their parents during routine preventive health care visits (43, 45). Parents can help their children and adolescents to follow the Dietary Guidelines for Americans at home and at school. These guidelines include recom- mendations to decrease consumption of fat, saturated fat, sodium, and added sugars; increase Table 2. The Effect of Weight on Birth Control Methods
Average Associated Does weight affect how well
Birth Control Method Weight Gain it prevents pregnancy?
Abstinence None No
Male condom None No
Female condom None No
Emergency contraception None No
Vaginal spermicide None No
Diaphragm None If gain or loss of 10 pounds or more occurs, it may need to be refitted Cervical cap None If gain or loss of 10 pounds or more
occurs, it may need to be refitted Combination oral None If weight is 176 pounds or contraceptives more, it may not prevent pregnancy
as well
Progestin-only oral None If weight is 176 pounds or contraceptives (mini pills) more, it may not prevent pregnancy
as well
Contraceptive injection 5 pounds in first year of use No
Vaginal ring None No
Patch None If weight is 176 pounds or more, it
may not prevent pregnancy as well
Copper T intrauterine device None No
Mirena intrauterine system None No
Sterilization None No
Created by the SAFE Study: Computer-Aided Counseling to Prevent Teen Pregnancy/STDs, Principal Investigator: Melanie A. Gold, D.O., University of Pittsburgh School of Medicine, supported by NICHD grant #HD41058. Modified and reprinted with permission.
consumption of fruit, vegetables, whole grains, and other foods that are rich in fiber; increase the con- sumption of milk or other foods or beverages that are good sources of calcium; and participate in at least 60 minutes of physical activity on most, preferably all, days of the week (45, 46). Adolescents can be encouraged to increase the amount of regular daily activity by making small lifestyle changes, such as climbing the stairs instead of taking an elevator. They also can be encouraged to choose an activity that can become a part of their everyday life, such as bicycling or walking. Leisure activities that are sedentary, such as television viewing and playing computer games, should be restricted to less than 2 hours per day. Parents also should be encouraged to model healthy eating habits and physical activity and should be informed that food should never be used as a tool for punishment or reward. Eating breakfast and regular meals is important to promot- ing and maintaining a healthy weight. A recent study funded by the National Institutes of Health moni- tored nearly 2,400 females aged 9–19 years for 10 years and found that those who regularly ate break- fast, particularly ones that included cereal, were slimmer than those who skipped the morning meal (47). Schools can support healthy behavior by using several means, including the provision of instruc- tion, the enactment of physical activity and nutrition policies, and by ensuring that the school environ- ment supports healthy eating and physical activity (48).