Abstract 5760: Trends in oral contraceptive and intrauterine device use among reproductive aged women in the US from 1999-2017
Authors: King Lauren A. , Michels Kara A. , Graubard Barry I. , Trabert Britton 
Published: September 2020

Abstract
Importance: Since the 1960s, an increase in the use of oral contraceptives (OC) and other hormonal contraceptives has mirrored a decreased incidence of ovarian and endometrial cancers in the US. With improved access and increased contraceptive options over time, it is important to follow trends of use and consider how changing patterns can affect gynecologic cancer risks.
Objective: To evaluate trends in OC use and intrauterine device (IUD) use among reproductive aged women in the US.
Methods: Nationally representative data from the National Health and Nutrition Examination Survey (NHANES, N=19,216) and the National Survey for Family Growth (NSFG, N=26,262) were used to determine current OC and IUD use among reproductive aged women in the US. Women with prior hysterectomy, bilateral oophorectomy or that were post-menopausal were excluded due to ineligibility for standard OCs. Adjusted logistic regression and unadjusted Joinpoint models (to determine inflection points) were used to evaluated trends in contraceptive use between 1999-2017. We used questionnaire data from continuous NHANES and NSFG cycles from 1999/2000 to 2015/16 and 2006/08 to 2015/17, respectively. Within each survey, temporal trends in OC use were assessed overall and by race, age, gravidity, education and BMI. OC formulation/generation were determined from current prescriptions in NHANES. Trends in IUD use were evaluated in NSFG.
Results: Since 1999, self-reported OC use overall decreased annually by 3% in NHANES [OR 0.97 (95%CI 0.96, 0.99) P=0.001] and 4% in NSFG [0.96 (0.94, 0.97) P&lt;0.001]. Annual percent change estimates from unadjusted joinpoint regression also suggested consistent decreases over time. Proportion of OC use by generation of progestin across all cycles was stable with an average of 42.3% 3rd generation, 31.3% 1st, 17.0% 2nd, and 9.5% 4th (the latter was limited to cycles from 2003/04 to 2015/16). Decreases in OC use over time did not vary by categories of race, age, education or BMI. However, trends in OC use varied significantly by gravidity in NHANES (Phet=0.05). OC use for nulligravid women was stable over time, while reported OC use decreased 4% annually in gravid women [OR 0.96 (0.94-0.98) P&lt;0.001]. IUD use increased by 14% each year [OR 1.14 (1.11, 1.17) P&lt;0.001]; 76.5% of users reported hormonal IUD use in the 2015/17 cycle. The largest uptake of IUD use (32% increase per year [OR 1.32 (1.21, 1.43) P&lt;0.001]) occurred among nulligravid women, which was historically, a contraindication for IUD use.
Conclusions: IUD use is increasing at a rate faster than that of the decreasing rate of OC use. There is some suggestion that like OC use, IUD use also reduces ovarian and endometrial cancer risks, although associations with hormonal IUDs are less clear. As such, the changing landscape of contraceptive practices in the US may alter future trends in ovarian and endometrial cancers and thus requires further surveillance.
Citation Format: Lauren A. King, Kara A. Michels, Barry I. Graubard, Britton Trabert. Trends in oral contraceptive and intrauterine device use among reproductive aged women in the US from 1999-2017 [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5760.