Inappropriate Use of Combined Hormonal Contraceptives for Birth Control Among Women of Reproductive Age in the United States

Abstract

Objective:

To describe the extent of inappropriate use of combined hormonal contraceptives (CHC) according to the United States Medical Eligibility Criteria (U.S. MEC).

Methods:

We analyzed Kantar Health's 2010 U.S. National Health and Wellness Survey data, which is an annual population-based survey of 75,000 U.S. adults via internet. A stratified random sampling framework was used to construct a sample that reflects the U.S. census by age, gender, and ethnicity. The analysis included nonpregnant females aged 18–44 years who used CHC, including oral, patch, or vaginal rings in the past 6 months. Women classified into category 3 (theoretical or proven risks usually outweigh the advantages of using the method) or 4 (unacceptable health risk) according to the U.S. MEC were defined as having high-risk conditions, or inappropriate CHC use. The proportions of women who had inappropriate CHC use were then projected to the U.S. population by diseases/conditions and demographic characteristics incorporating sampling weights.

Results:

We identified 2963 adult females of reproductive age (mean 29.3±6.0) (i.e., 20.4% of all adult females of reproductive age in the database) as being CHC users. Among them, 23.7% (95% CI: 22.8%–24.5%) had at least one high-risk condition and 9.3% (95% CI: 9.2%–9.4%) had at least one condition of unacceptable risk. The three most common high-risk conditions were migraine (12.7%), multiple risk factors for arterial cardiovascular disease (9.3%), and hypertension (6.1%). Women with relatively higher proportions of inappropriate CHC use were age ≥35, not finished college, and Medicaid recipients.

Conclusions:

A large portion of women used CHC inappropriately. Hormone-free and progestin-only contraceptives are available options with potentially less risk for them.

Introduction

Preventing unintended pregnancy is a personal goal for most couples, and reducing the national level of unintended pregnancy is one of the most important reproductive health goals identified by the U.S. Department of Health and Human Services.¹ Women who have an unintended pregnancy are also at risk for subsequent unplanned childbearing and births, which is associated with a number of adverse maternal behaviors and child health outcomes. According to Guttmacher Institute's most recent analysis, of the 6.7 million pregnancies in the United States in 2006, nearly half (49%) were unintended. Although some unintended pregnancies are accepted or even welcomed, more than four in ten (43%) end in abortion. Unintended pregnancy rates increased among poor and low-income women (a 50% rise from 1994 to 2006), women aged 18–24 years, cohabiting women, and minority women.²

Hormonal contraceptives are widely used in the United States as a method to prevent unintended pregnancy. There are 62 million U.S. women in their childbearing years (15–44).³ Seven in 10 women of reproductive age (43 million women) are sexually active and do not want to become pregnant but could become pregnant if they and their partners fail to use a contraceptive. Among the 43 million fertile, sexually active women who do not want to become pregnant, 86% are practicing some form of contraception and 30% use hormonal contraceptive methods (pill, injection, patch, implant, and ring). Contraceptive choices vary markedly with age. For women younger than 30, the pill is the leading method. Among women aged 30 years and older, more rely on sterilization.⁴

Many elements need to be considered by women at any given point in their lifetimes when choosing the most appropriate contraceptive method. These elements include safety, effectiveness, availability, and acceptability. Using contraceptives can carry certain risk for women, especially for those with some medical conditions. Early epidemiologic research showed an increased risk for cardiovascular events, particularly venous thromboembolism (VTE), in women using high-dose combined hormonal contraceptives (CHC).⁵ The mechanism by which CHCs increase risk of VTE is mostly related with the estrogen component in CHC, but the net effect of estrogen on cardiovascular risk is not yet well defined.^6,7 However, it's important to note that women experience a significantly increased risk for VTE during pregnancy and peripartum period, and using CHC might actually decrease the overall rate of VTE in the population through reduction in unintended pregnancies.

Many patients and health care providers have misperception about contraceptive risks and benefits, and it is critical to help them make informed choices about contraceptive methods. Evidence-based guidance is one tool that can assist providers in assessing risks and benefits. The Centers for Disease Control and Prevention (CDC) published the U.S. Medical Eligibility Criteria for Contraceptive Use, 2010 (U.S. MEC), which was mostly adapted from the fourth edition of World Health Organization (WHO) MEC, published in 2009.⁸ Subsequently, CDC issued an update with revised recommendations for the use of contraceptive methods during the postpartum period in July of 2011 and an update for hormonal contraceptive use for women at high risk for HIV or infected with HIV in June of 2012.^9,10 The purpose of the U.S. MEC is to assist healthcare providers in counseling about contraceptive method choice and to serve as a source of clinical evidence. This guidance document should help providers in assessing contraceptive safety for specific women, especially women with serious medical conditions, who need to choose a method that they can use effectively in order to prevent serious sequelae associated with unintended pregnancy.¹¹

The U.S. MEC for contraceptive use classified CHC methods (including pills, patches, or vaginal rings) into four categories (Table 1). Category 1 comprises conditions for which no restrictions exist for use of the contraceptive method. Category 2 includes conditions for which the advantages of using CHC generally outweigh the theoretical or proven risks, indicates CHC generally can be used, but careful follow-up may be required. For a method/condition classified as Category 3, the theoretical or proven risks usually outweigh the advantages of using CHC. Therefore, use of CHC usually is not recommended unless other more appropriate methods are not available or acceptable. The severity of the condition and the availability, practicality, and acceptability of alternative methods should be taken into account, and careful follow-up will be required. Category 4 is composed of conditions that represent an unacceptable health risk if CHC is used. For example, a cigarette smoker aged <35 years generally can use CHCs (Category 2); however, for a woman ≥35 years of age who smokes <15 cigarettes per day, use of CHCs usually is not recommended unless other methods are not available or acceptable to her (Category 3). A woman ≥35 years of age who smokes ≥15 cigarettes per day should not use CHCs because of unacceptable health risks, primarily the risk for myocardial infarction and stroke (Category 4).⁸

Table 1.

Definitions of U.S. Medical Eligibility Criteria Categories for Use of Hormonal Contraception, Intrauterine Devices, and Barrier Methods

Category	Definition of category
1	A condition for which there is no restriction for the use of the contraceptive method
2	A condition where the advantages of using the method generally outweigh the theoretical or proven risks
3	A condition where the theoretical or proven risks usually outweigh the advantages of using the method
4	A condition, which represents an unacceptable health risk if the contraceptive method is used

Source: Centers for Disease Control and Prevention. U.S. Medical Eligibility Criteria for Contraceptive Use, 2010. Available at http://www.cdc.gov/mmwr/pdf/rr/rr59e0528.pdf

Use of CHC consistent with the U.S. MEC is essential in ensuring safe use of contraceptives. There is a shortage of data on whether or how widely contraceptive methods have been appropriately used according to the U.S. MEC in clinical practice. To fill the information gap, we analyzed Kantar Health's 2010 National Health and Wellness Survey (NHWS) U.S. data to estimate the extent of inappropriate use of combined hormonal contraceptives (CHC), including pills, patches, or vaginal rings, among adult females of reproductive age in the United States. Compared with the National Survey of Family Growth (NSFG) population, women of reproductive age included in the NHWS had similar hormonal contraceptive use rate (among all sexually active women who do not want to become pregnant, 33% of those age 18–44 in NHWS versus 30% of those age 15–44 in NSFG) and similar age structure (66% of women younger than 35 in NSFG vs. 67% in NHWS).⁴ Therefore, NHWS data can be utilized as a national representative population for an estimation of women's contraceptive use.

Materials and Methods

Data source

We examined CHC use by analyzing Kantar Health's 2010 National Health and Wellness Survey (NHWS) U.S. data. Kantar Health's NHWS is the largest international self-reported patient survey database in the healthcare industry, with annual survey responses dating back to 1998, 2000, and 2008 in the United States, Europe, and Asia, respectively. The U.S. NHWS is an annual, cross-sectional survey of 75,000 U.S. adults 18 years of age and older. The NHWS includes questions regarding over 165 diagnosed medical conditions, experience with prescription medication use for those conditions, health-related attitudes, and behaviors. The type and amount of healthcare resources used are assessed with a 6-month recall period, and three separate fielding periods spaced over the course of the year to minimize potential seasonal variability. For 2010 NHWS, data were collected during the first three quarters of 2010.

The NHWS has been administered annually via internet since 2002. Potential respondents to the NHWS were recruited through an existing consumer panel of approximately 3 million U.S. residents. The consumer panel recruits its members through opt-in emails, co-registration with panel partners, e-newsletter campaigns, and online banner placements. All panelists explicitly agreed to be a panel member and registered with the panel through a unique email address. A stratified random sampling framework (with quotas based on gender, age, and race/ethnicity) was implemented within this panel to construct a sample for the NHWS that matches the U.S. census according to age, gender, and ethnicity.

Variables included in the NHWS database include demographic information of the surveyed population (age, gender, race/ethnicity, income, education, family history, body mass index, prescription coverage, and health insurance, etc.); prevalence and incidence, treatment, and disease history; presence of comorbidities, quality of life and work productivity, time lapse since diagnosis, and so on. The NHWS includes a section for women's health, in which information on contraceptive use was collected.

Inclusion criteria

The respondents in 2010 U.S. NHWS database who met the criteria below were included in the analysis.

1. Female aged 18–44 years,

2. Currently not pregnant, and

3. Indicated that they used combined hormonal contraceptives (for birth control), including pills, patch, or vaginal rings, in the past 6 months.

Variable definition

Use of combined hormonal contraceptives, including pills, patch, or vaginal rings, was flagged based on how participants responded to two questions: (1) whether they selected one or more of pills (for birth control), patch, or vaginal ring in response to the question “which of the following have you used in the past 6 months”; and (2) for the question “please indicate which of the following prescription medications you currently use for birth control or other reasons,” whether they selected any (only one) of the compounds indicating ingredients of both estrogen and progestin.

Women who fall into category 3 (risks usually outweigh benefits) or category 4 (unacceptable health risks) according to the U.S. MEC for contraceptives (Table 1) were defined as having high-risk conditions (i.e., they had inappropriate use of CHC). Table 2 describes the details of each disease/condition included in a high-risk condition category in this study. High-risk conditions that can be identified in NHWS database were breast cancer, deep venous thrombosis (DVT)/pulmonary embolism (PE), diabetes mellitus (DM) related conditions, migraine headaches, hypertension, ischemic heart disease (IHD), liver tumors, multiple risk factors for arterial cardiovascular disease (CV), smoking (current), stroke, valvular heart disease, and using anticonvulsant therapy. High-risk conditions that cannot be identified in NHWS data include <1 month postpartum breastfeeding, severe cirrhosis, peripartum cardiomyopathy, <21 days postpartum, complicated solid organ transplantation, viral hepatitis, antiretroviral therapy (ritonavir-boosted protease inhibitors), antimicrobial therapy (rifampicin or rifabutin therapy), etc. Women initiating CHC cannot be differentiated from those who had previously initiated CHC and it is assumed that all of them had started CHCs at some time prior to the responding to the survey in this study.

Table 2.

High-Risk Conditions Defined and Identified in the Study

	Category in U.S. MEC for CHC (pill, ring, and patch)
Condition	I	C	Category in the study
Breast cancer			High-risk condition^a
(a) Current	4		^*Unacceptable risk condition^b
(b) Past and no evidence of current disease for 5 years	3
Deep venous thrombosis (DVT)/Pulmonary embolism (PE)			High-risk condition
Diabetes mellitus (DM) related conditions			High-risk condition
(a) Nephropathy/retinopathy/neuropathy	3/4		3/4 undifferentiable^c
(b) Other vascular disease or diabetes of >20 years' duration	3/4		3/4 undifferentiable
Migraine headaches			High-risk condition
(a) without aura, age <35	2	3
(b) without aura, age >35	3	4	^*Unacceptable risk condition
(c) with aura, any age	4	4	^*Unacceptable risk condition
Hypertension			High-risk condition
(a) Adequately controlled hypertension	3
(b) Elevated blood pressure levels
(i) systolic 140–159 or diastolic 90–99	3
(ii) systolic ≥160 or diastolic ≥100	4		^*Unacceptable risk condition
(c) Vascular disease	4		^*Unacceptable risk condition
Ischemic heart disease (current and past)	4		High-risk condition ^*Unacceptable risk condition
Liver tumors			High-risk condition^*Unacceptable risk condition
(a) Benign
(i) Hepatocellular adenoma	4		^*Unacceptable risk condition
(b) Malignant	4		^*Unacceptable risk condition (include small cell lung cancer and non-small cell lung cancer identified)
Multiple risk factors for arterial cardiovascular disease			High-risk condition
At least having two of older age, obesity, smoking, diabetes and hypertension	3/4		3/4 undifferentiable
Smoking			High-risk condition
(a) Age >35, <15 cigarettes/day (b) Age >35, >15 cigarettes/day	34		3/4 undifferentiable (No number cigarettes/day information available in NHWS)
Stroke	4		High-risk condition ^*Unacceptable risk condition
Valvular heart disease – complicated	4		High-risk condition ^*Unacceptable risk condition
Anticonvulsant therapy			High-risk condition
(a) Certain anticonvulsants (phenytoin, carbamazepine, barbiturates, primidone, topiramate, oxcarbazepine)	3		Only topiramate, oxcarbazepine, and lamotrigine use can be identified in NHWS
(b) Lamotrigine	3

Source: Centers for Disease Control and Prevention. U.S. Medical Eligibility Criteria for Contraceptive Use, 2010. Available at http://www.cdc.gov/mmwr/pdf/rr/rr59e0528.pdf

High-risk conditions are those conditions where theoretical or proven risks usually outweigh the advantages (category 3) or those with unacceptable health risk (category 4).

Unacceptable risk condition refers to those conditions with unacceptable health risk (method not to be used), defined as category 4 in U.S. MEC.

3/4 undifferentiable are those that were defined as 3/4 in U.S. MEC, or those that there were classified as not having enough information in NHWS data to differentiate between risk category 3 and 4. They were included in high-risk condition but not in unacceptable risk condition in the analysis.

C, continuation of contraceptive method; CHC, combined hormonal contraceptives; I, initiation of contraceptive method; NHWS, National Health and Wellness Survey; U.S. MEC, United States Medical Eligibility Criteria.

The unacceptable health risk conditions identified in this study included breast cancer (current), migraine (without aura and age ≥35, or with aura and of any age), hypertension (systolic blood pressure [BP] ≥160, or diastolic BP ≥100, or with vascular disease), IHD, liver tumor, stroke, and complicated valvular heart disease. Some conditions/diseases were category 3/4 in the U.S. MEC but cannot be differentiated between category 3 and 4 using NHWS data. Those conditions were DVT/PE, DM related conditions, multiple risk factors for arterial CV, smokers (quantity of cigarettes per day information not available). They were not considered as unacceptable health risk conditions in main analysis.

Most of those conditions were identified from two questions: “have you experienced the condition in the past 12 months” and “has the condition been diagnosed by a physician.” For those identified with migraine, they were further categorized based on answers to another question regarding experience of symptoms (aura, see spots/flashing lights/heat wave, etc.). For identified women with diabetes, they were further categorized based on responses to the question “as a result of your diabetes, with which of the following complications have you ever been diagnosed” for complications such as nephropathy, retinopathy, and neuropathy and the question “what year was your diabetes diagnosed” for diabetes of more than 20 years' duration. Hypertension was defined by evaluating the systolic and diastolic BP reported (systolic BP ≥140 or diastolic BP ≥90 for high-risk category, and systolic BP ≥160 or diastolic BP ≥100 for unacceptable risk category). Obesity was defined by body mass index (BMI) measures (BMI ≥30) calculated from weight and heights reported in the survey.

Analysis

The number and proportion of women who had inappropriate use of CHC were tabulated and projected to the U.S. population, by disease group and by patient characteristics. Patient characteristics included age (18–34, 35 and above), race/ethnic group (white, African American, Hispanic, Asian or Pacific Islander, others), education (less than college graduate, college graduate, or above), marriage status (married, single and never married, divorced/separated/widowed, or living with partner), household income level per year (<$25k, $25k to <$50k, $50k to <$75k, $75k and more, or declined to answer), and health insurance coverage (employer-based, individual/family plans, Medicaid, Medicare, VA/CHAMPUS or TRICARE, or other/unknown), and whether requested the brand from doctors (yes, no). Proportion of women who had unacceptable health risk condition (category 4) was also tabulated by disease conditions and patient characteristics.

Productive Access, Inc. (PAI)'s web-hosted mTAB™ survey analysis software was used for the analysis of NHWS data. Appropriate survey weights were applied in all of analysis when the data was extrapolated to the U.S. population. Weighting variables included gender, age, and race/ethnicity. Both the number of sample population and corresponding weighted number of population for each set of analysis were reported. Ninety-five percent confidence intervals (CI) were calculated and reported for proportion numbers. The differences between groups were considered statistically significant if 95% CI ranges do not overlap.

Results

In the 2010 U.S. NHWS database, 14,905 nonpregnant adult females of reproductive age were identified, who are considered to represent 45.44 million (weighted number) of the women in the United States. Of those 14,905 women, 2,963 (19.9% of all nonpregnant women aged 18–44) were using CHC in the past 6 months, which represents 9.25 million (weighted) women in the United States. Below results are based on the analysis of the 2,963 CHC users.

The demographic and socioeconomic characteristics for CHC users are presented in Table 3. The mean age was 29.3 years (standard deviation 6.0) and 79.5% were less than 35 years old. In terms of racial/ethnic group, 63.3% were white, 13.0% African American, 10.3% Hispanic, 8.6% Asian or Pacific Islander, and 4.8% unknown. With respect to education, 54.4% of them had graduated college or above. Among CHC users, 44.3% were married and 38.7% were single (never married), 4.6% were divorced, separated, or widowed, and 12.4% were living with partner; 42.2% had household income of less than $50k. Most women (65.7%) were covered by employer-based insurance, and the rest had individual/family insurance plans (9.4%), Medicaid (4.5%), Medicare (2.1%), or other (18.3%). Finally, 33.9% of women reported that they requested the brand of contraceptive from their doctors; A majority of these women (86.5%) were pill users, 11.6% were ring users, and 2.9% were patch users.

Table 3.

Basic Characteristics of CHC Users

	n (sample)	Unweighted %	Weighted n	Weighted %
Female, 18–44 years old and using CHC (CHC users)	2,963	100.0%	9,253,865	100.0%
Age: mean (SD)	29.3 (6.0)
Age group
18–34	2,356	79.5%	7,459,746	80.6%
35–44	607	20.5%	1,794,119	19.4%
Racial/ethnical group
White	1,875	63.3%	6,277,015	67.8%
African American	386	13.0%	1,016,681	11.0%
Hispanic	306	10.3%	1,374,353	14.9%
Asian or Pacific Islander	254	8.6%	377,160	4.1%
Other/unknown	142	4.8%	208,656	2.3%
Education level
Less than college graduate	1,342	45.3%	4,348,631	47.0%
College graduate or above	1,611	54.4%	4,905,234	53.0%
Marriage status
Married	1,312	44.3%	4,124,140	44.6%
Single, never married	1,147	38.7%	3,505,449	37.9%
Divorced/separated/widowed	136	4.6%	412,433	4.5%
Living with partner	368	12.4%	1,211,843	13.1%
Household income
Less than $25,000	420	14.2%	1,323,927	14.3%
$25,000 to <$50,000	830	28.0%	2,639,770	28.5%
$50,000 to <$75,000	664	22.4%	2,103,980	22.7%
$75,000 or more	827	27.9%	2,527,347	27.3%
Declined to answer	222	7.5%	658,841	7.1%
Insurance type
Employer-based insurance	1,948	65.7%	6,060,019	65.5%
Individual/family insurance plans	278	9.4%	862,543	9.3%
Medicaid	134	4.5%	421,910	4.6%
Medicare	61	2.1%	186,535	2.0%
Other or no response	542	18.3%	1,722,858	18.6%
Request the brand from doctor
Yes	1,005	33.9%	3,139,100	33.9%
No	1,958	66.1%	6,114,765	66.1%

Figure 1 presents the proportion of inappropriate CHC use among all CHC users identified. Overall, 23.3% (95% CI: 21.8%–24.8%) had at least one high-risk condition, which translated into 2.19 million adult women in the United States. The three most common high-risk conditions were migraine (12.3%, 95% CI: 11.1%–13.5%), multiple risk factors for arterial CV (9.2%, 95% CI: 8.2%–10.3%), and hypertension (6.3%, 95% CI: 5.4%–7.2%). It is worth noting that of the 273 women with multiple risk factors for arterial cardiovascular disease, 39.4% were obese (BMI ≥30 kg/m²) and 26.8% were current smokers. Other high-risk conditions included taking anticonvulsant medications (1.6%, 95% CI: 1.1%–2.0%), smoking, and age ≥35 years (1.2%, 0.8%–1.6%), diabetes-related conditions (0.4%, 95% CI: 0.2%–0.6%), IHD (0.3%, 0.1%–0.5%), DVT/PE (0.2%, 95% CI: 0.0%–0.4%), stroke (0.2%, 95% CI: 0.0%–0.3%), valvular heart disease (0.1%, 95% CI: 0.0–0.3%), and breast cancer (0.03%, 95% CI: 0.0%–0.1%). Inappropriate use rates did not significantly differ between users of different contraceptive methods: 23.1% (95% CI: 21.5%–24.8%) among pill users, 26.3% (95% CI: 21.7%–31.0%) among ring users, and 19.1% (95% CI: 10.7%–27.5%) among patch users.

FIG. 1.

Combined hormonal contraceptive (CHC) users with at least one high risk condition.

Figure 2 presents the results for the proportion of women having unacceptable risk conditions by disease/condition. Overall, 9.2% (95% CI: 8.2%–10.3%) of all CHC users had at least one condition of unacceptable risk. This corresponds to approximate 0.86 million women in the United States. The most common condition with unacceptable risk identified was migraine headache (without aura and age ≥35 years, or with aura of any age), which was 7.7% (95% CI: 6.8%–8.7%) of the CHC users. The other conditions with unacceptable risk included hypertension (SBP ≥160 mmHg or DBP ≥100 mmHg) or vascular disease (1.1%, 95 % CI: 0.8%–1.5%), IHD (0.5%, 95% CI: 0.2%–0.7%), stroke (0.2%, 95% CI: 0.1%–0.4%), valvular heart disease (0.2%, 95% CI: 0.0%–0.4%). Having multiple risk factors for arterial CV (9.2% of CHC users) was not considered as an unacceptable risk condition in the main analysis because it is listed as category 3/4 (undifferentiable) in the U.S. MEC. In sensitivity analysis that included all undifferentiable 3-/4-category conditions (DVT/PE, DM conditions, multiple risk factors for CV, smokers ≥35 years old) as unacceptable risk conditions, 17.7% (95% CI: 16.3%–19.1%) of all CHC users had unacceptable risk.

FIG. 2.

CHC users with unacceptable risk conditions.

Table 4 displays inappropriate CHC use by patient characteristics. Women 35 years of age and above (31.1%, 95% CI: 27.5%–34.8%) had relatively higher proportions of inappropriate CHC use than did women less than 35 years of age (21.3%, 95% CI: 19.7%–23.0%). The proportion of inappropriate CHC use among women of Asian and Pacific Islander origins (12.6%, 95% CI: 8.5%–16.7%) was about half of that among white women (25.6%, 95% CI: 23.6%–27.5%). Those who had less education than a college graduate (26.9%, 95% CI: 24.5%–29.3%) had significantly higher inappropriate CHC use than those who had college degree or above (20.5%, 95% CI: 18.5%–22.5%). Compared with women covered by employer-based insurance (23.7%, 95% CI: 21.8%–25.6%), those with individual/family insurance plans (16.9%, 95% CI: 12.5%–21.3%) were less likely, and those covered by Medicaid (35.8%, 95% CI: 27.7%–43.9%) were more likely, to use CHC inappropriately.

Table 4.

Inappropriate CHC Use by Women's Basic Characteristics

			Proportion of inappropriate CHC use among all CHC users^b
	Inappropriate CHC use^a		Unweighted %
	n (sample)	Weighted n	%	95% CI		p<0.05
Total	691	2,189,194	23.3%	21.8%	24.8%
Age group
18–34	502	1,639,451	21.3%	19.65%	23.0%	Reference
35–44	189	549,743	31.1%	27.45%	34.8%	^*
Racial/ethnic group
White	479	1,592,904	25.6%	23.57%	27.5%	Reference
African American	85	217,870	22.0%	17.89%	26.2%
Hispanic	63	281,830	20.6%	16.06%	25.1%
Asian or Pacific Islander	32	48,050	12.6%	8.52%	16.7%	^*
Other/unknown	32	47,540	22.5%	15.66%	29.4%
Education level
Less than college graduate	361	1,168,305	26.9%	24.53%	29.3%	Reference
College graduate or above	330	1,020,889	20.5%	18.51%	22.5%	^*
Marriage status
Married	320	1,006,779	24.4%	22.07%	26.7%	Reference
Single, never married	236	744,670	20.6%	18.24%	22.9%
Divorced/separated/widowed	42	123,684	30.9%	23.12%	38.7%
Living with partner	93	314,061	25.3%	20.83%	29.7%
Household income
Less than $25,000	102	333,263	24.3%	20.18%	28.4%	Reference
$25,000 to <$50,000	219	703,859	26.4%	23.39%	29.4%
$50,000 to <$75,000	158	536,521	23.8%	20.56%	27.0%
$75,000 or more	177	503,008	21.4%	18.61%	24.2%
Declined to answer	35	105,406	15.8%	10.97%	20.6%
Insurance type
Employer-based insurance	461	1,449,015	23.7%	21.78%	25.6%	Reference
Individual/family insurance	47	156,313	16.9%	12.50%	21.3%	^*
Medicaid	48	149,854	35.8%	27.70%	43.9%	^*
Medicare	12	39,982	19.7%	9.70%	29.7%
VA/CHAMPUS, TRICARE	29	87,132	28.7%	19.89%	37.5%
Not sure no response	119	384,610	22.0%	18.47%	25.4%
Request the brand from doctor
Yes	239	760,993	23.8%	21.15%	26.4%	Reference
No	452	1,428,201	23.1%	21.22%	25.0%

Indicates p<0.05. That is, the 95% confidence interval (CI) of the group did not overlap with that of the reference.

Inappropriate CHC use includes those women 18–44 years old with CHC use and at least one high-risk condition.

Proportion of inappropriate CHC use is the percentage of inappropriate CHC use among CHC users for each characteristics group.

Discussion

The 2010 NHWS data show that a large proportion of women used CHC inappropriately according to the U.S. MEC for contraceptive use. In this study, 23.3% of those adult women who were using CHC [i.e., 2.19 million women (estimated) in the United States] had at least one high-risk condition. The three most common high-risk conditions identified in this study were migraine headache, multiple risk factors for arterial cardiovascular disease, and hypertension. Furthermore, 9.2% of all CHC users had at least one condition of unacceptable health risk, which predominantly consisted of women with migraine headache and hypertension. At the population level, this corresponds to 860,000 women in the United States. To the best of our knowledge, this study provided the first description on whether CHCs were appropriately used among women since the publication of the U.S. MEC.

In 2010 an estimated 2.19 million women in the United States were using CHCs even though they had a category 3 or 4 risk factor, which is defined by the U.S. MEC as outweighing the advantages of using CHCs or representing an unacceptable health risk. This highlights that a high number of women in the United States were taking CHCs despite having a risk of cardiovascular events. Among them, 860,000 thousand CHC users had a medical condition with unacceptable health risk using CHC. It points to the need to train and educate healthcare providers and women to make informed decision about the benefits and risks of various contraceptive methods.

Access to safe and effective contraception is critical for women with underlying medical conditions, as they may face heightened risks in pregnancy and/or elevated risk of cardiovascular disease. In order to appropriately manage contraceptive use by women, healthcare providers need to identify women with high-risk conditions for CHC use. Women35 years and older should be assessed for cardiovascular risk factors including hypertension, smoking, diabetes, nephropathy, and other vascular diseases, including migraines, prior to use. For example, for women with recurrent episodic headaches, it is important to differentiate migraine from non-migraine headaches and seek headache specialist or neurologist consultation if necessary. Women's blood pressure should always be monitored before prescribing a contraceptive method. If a woman has a history of idiopathic or postpartum DVT or VTE, she may be predisposed to recurrence if exposed to exogenous estrogen.

For women diagnosed with high-risk conditions for CHC use, alternative methods that have lower associated CV risk are available. Generally for women with medical conditions associated with increased risk for cardiovascular disease or VTE risk such as hypertension and DVT/VTE history, progestin-only methods and intrauterine devices (IUDs) do not increase risk of venous thrombosis and are a safe and effective choice. For women with headaches, if menstrual migraine headaches without aura and other risk factors, it is suggested to use CHC in extended regimen; if migraines without aura, progestin-only methods and IUDs are safe and effective methods; and if migraines with aura, non-hormone-medicated (copper) IUD is a safe method.^12,13 For women with complicated or long-standing diabetes, IUDs are a safe and effective choice, while some progestin only methods may cause insulin resistance and increases in blood glucose, though usually clinically insignificant.^8,12,13 For women on antiepileptic drugs, the ideal contraceptives are IUDs, and progestin-only contraceptives should be avoided or used with barrier methods because enzyme-inducing antiepileptic medications can speed up the breakdown of hormones and make hormonal contraceptives less effective.^12,13,14 However, this is not an exhaustive list here. Physicians should refer to the U.S. MEC for guidance on selecting safe contraceptive methods for women with specific medical conditions.

This study also found that the inappropriate use of CHC varied among women of different social and demographic characteristic groups. The proportion of high-risk CHC users among Asian women were significantly lower than among white women. This could be related with the generally lower prevalence of those high-risk conditions, such as migraine, hypertension, risk factors for cardiovascular disease, and diabetes, among Asian women than white women.^15,16 Women who had education less than a college degree had a higher proportion of high-risk CHC users than those with a college degree or above, and they should be given more attention in related health education programs. Women covered by Medicaid were more likely to use CHC even with high-risk conditions, compared with those covered by employer-sponsored insurance. Medicaid recipients have been reported to have less access to prescription drugs and choice of care providers than those with private insurance,¹⁷ which could partially explain the higher inappropriate use of CHC among them.

The U.S. MEC mostly agrees with the WHO MEC, but in cases where the guidance is different, the U.S. MEC is generally but not always less restrictive than the WHO MEC.^8,9,10 It is expected that the results of this study should not change with WHO guidance applied to the U.S. population, since most of the high-risk conditions were defined the same in the two MECs and for those not consistent (breastfeeding, peripartum cardiomyopathy, and solid organ transplant) they cannot be identified with NHWS database.

This study has several limitations. First, a few infrequent high-risk medical conditions could not be identified using NHWS database, such as less than 21 days postpartum, less than a month postpartum breastfeeding, and viral hepatitis. Not capturing those conditions in the analysis could lead to an underestimation of the proportion of high-risk CHC use. However, most of those unidentifiable high-risk conditions are of low prevalence, and the impact of the omission should be small. Secondly, in comparing between groups, for example, between women of different insurance coverage, multiplicity adjustment could not be made for a conservative comparison between groups, and multivariate analysis could not be conducted to control for potential confounders, because the NHWS data can only be accessed through web-hosted mTAB™ survey analysis software. Thirdly, all responses recorded in NHWS data are self-reported through internet surveys and may be subject to sampling bias and response bias as well as recall errors. A recall error on the contraceptive used could lead to misclassification of a non-CHC user as a CHC user, but since the contraceptive used was verified by two questions (as described in the variable definition section), such misclassification is very unlikely to occur. Also, response bias and recall errors in some health conditions such as migraine could result in overestimation of the inappropriate use. To minimize such bias, those high-risk health conditions were verified by multiple questions. For example, migraine condition was verified by three questions (experiencing symptoms in the past 12 months, diagnosis by physician, and specific symptoms experienced), and hypertension was accessed with both experience of condition in the past 12 months and values of blood pressure readings. Fourthly, data is not available in NHWS data to explore whether the observed inappropriate use was consequence of a wrong prescription by health care providers or due to those women's wrong judgment.

Lastly, it is worth noting that for most healthy women of reproductive age, the benefits of contraceptive use outweigh the risks. To put the risk of VTE for CHC users into perspective, there is a VTE risk of approximately 4–5 per 10,000 woman years in women not using hormonal contraception, while in the absence of reliable contraception, women of reproductive age face risks of VTE associated with pregnancy of up to 29 per 10,000 woman-years, and in the immediate postpartum period this risk is as high as 300–400 per 10,000 woman-years.^18

–21 Prospective observational studies have shown that all currently available CHCs increase the risk of VTE to the range of 9–10 per 10,000 woman-years of use and that this risk is highest in the first few months of use, with a fall towards baseline risk thereafter.²² The occurrence of serious events such as pulmonary embolism are rare with contemporary CHCs. Modern CHCs offer excellent contraceptive efficacy and reduce rates of unplanned pregnancies. Therefore, CHCs may actually decrease the overall rate of VTE in the population compared with rates in populations without access to effective contraception. But individualized risk assessment should always be undertaken to identify women who would be better advised to use other forms of contraception.

Conclusions

For decades, CHCs have been used as an effective and convenient method to prevent unintended pregnancy. This study found that a substantial proportion of women in the United States were using CHCs incongruent with the 2010 U.S. MEC for contraceptive use. The inappropriate CHC use may be associated with elevated risk for cardiovascular disease and/or reduction in the intended contraceptive effect. To effectively prevent unintended pregnancy and minimize unnecessary health risk, other contraceptive methods such as progestin-only methods or IUDs are available safe and effective options. Also, newer generations of CHC with low-dose estrogen have been developed with the intent of improving CHC safety and tolerability without compromising effectiveness. Training and/or educational information should be provided to health care providers and women (especially those with low education and Medicaid recipients) to help them make an informed choice on contraceptive methods.

Footnotes

Disclosure Statement

J.Y. and H.H are full-time employees of Merck & Co., Inc.

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