Table 3.

Pregnancy

Author, year, location, sources of support	Study design, follow-up	Population, intervention	Type(s) of IUD	Outcomes of interest	Results	Strengths	Weaknesses	Grade
Alton, 2012 [11] United States Source of support not stated	Retrospective cohort (chart review), 3 sites Up to 7 years follow-up Up to 80.88 person-years among women age <18 Up to 330.52 person-years among women age 18–21	Women aged ≤ 21 (range 11–21 years) having IUD inserted (n=233) Age <18: n=69 Age 18–21: n=164	LNG-IUD (n=222) CuT380A (n=11)	Pregnancy	No pregnancies with IUD in place (pregnancy data missing for 10 patients)	Multicenter trial (3 sites), diverse population	Small sample and few events; no information on study power No information on mean time to follow-up or on those lost from database All data from chart review; outcomes may be underestimated if women sought care from other sites	II-2, poor
Aoun, 2014 [12] United States No financial disclosures	Retrospective cohort Mean follow-up 37±11 months (range 19–57 months)	Women age 13–35 years who had LNG-IUD or Cu-IUD inserted for contraception (n=2138) Age 13–19: n=249 Age 20–24: n=750 Age 25–35: n=1139	LNG-IUD (n=1746) Cu-IUD (n=392)	Contraceptive Failure	Adjusted HR (95% CI) (reference group age 13–19): Age 20–24: 0.98 (0.30–3.13); p=.97 Age 25–35: 0.48 (0.15–1.59); p=.23	Multicenter Reviewed charts from office, emergency department and hospitals including laboratory and imaging results Multivariate analysis adjusted for age, race and IUD type Excluded those with no follow-up	Age groups differed by parity, gravidity, marital status, insurance but not tested in multivariate model No power calculation	II-2, fair
Behringer, 2011 [13] United States Doris Duke Charitable Foundation; NIH	Retrospective cohort 69.2% of sample (n= 573) returned to study clinic at least once 47.2% of sample (n=391) ≥1 year of follow-up	Women aged 14–50 years who received LNG-IUD (n=828) Age ≤21: n=131 Age> 21: n=697	LNG-IUD	Pregnancy	Frequency of method failure as reason for IUD removal among all women with insertion: No pregnancies among women age < 21 3 pregnancies among 697 women age ≥ 21 (0.4%) p=.71	Analyzed all those with IUD insertion and those who came back for follow-up to assess potential bias through loss to follow-up for discontinuation outcome (similar results were observed)	All data from chart review from single site; outcomes may be underestimated if women sought care from other sites. Powered to detect differences in discontinuation between adolescents and older women, not our outcome of interest, coupled with few reported events High proportion of adolescents that were parous (82%) Groups differed at baseline by race, marital status and parity	II-2, fair
Berenson, 2015 [15] United States Institute for Translational Sciences, University of Texas Medical Branch, Clinical and Translational Science Award; NIH	Retrospective cohort Nationwide US health insurance program 12 months	Women age 15–44 years with insurance claim for insertion of IUD (n=79,920) or ENG implant (n=7374) Age 15–19: ENG: n=2388 LNG: n=2204 Age 20–24: ENG: n=2014 LNG: n=8988	LNG-IUD	Pregnancy	Adjusted OR(95% CI) for complication with ENG implant vs. LNG-IUD: Age 15–19: Normal pregnancy: 0.40 (0.21–0.75); significant interaction of age and contraceptive method (p<.05) Ectopic pregnancy: 0.92 (0.06–14.8) Abnormal pregnancy or spontaneous abortion: 1.29 (0.41–4.08) Age 20–24: Normal pregnancy: 0.68 (0.41–1.12); significant interaction of age and contraceptive method Ectopic pregnancy: 0.56 (0.07–4.46) Abnormal pregnancy or spontaneous abortion: 2.24 (1.05–4.79)	Large sample size Reported both normal and abnormal/ectopic pregnancies Multivariate analyses performed for each outcome, adjusted for age at insertion, contraceptive type, provider type and year of insertion Excluded women without 12 months of continuous insurance coverage	Limited by diagnostic coding; potential underreporting of outcomes not captured in database Did not include parity as potential confounder	II-2, fair
Berenson, 2013 [14] United States Society for Family Planning; NIH	Retrospective cohort Nationwide US health insurance program 12 months (58% of those with IUD insertion also had 12 months of continuous insurance coverage and included in the analysis)	Women age 15–44 with an insurance claim for IUD insertion (n=90,489) Age 15–19: LNG-IUD: n=1528 CuT IUD: n=307 Age 20–24: LNG-IUD: n=7860 CuT IUD: n=2027 Age 25–44: LNG-IUD: n=61,197 CuT IUD: n=17,570	LNG-IUD Cu-IUD	Pregnancy	Ectopic Pregnancy: Adjusted OR for ectopic pregnancy (women age 15–19 vs. age 20–24): 0.57 (95% CI: 0.07–4.48) Adjusted OR for ectopic pregnancy (women age 15–19 vs. age 25–44): 0.76 (95% CI: 0.20–2.85) Abnormal Pregnancy or Spontaneous Abortion: Adjusted OR for abnormal pregnancy/spontaneous abortion for women age 15–19 vs. age 20–24: 0.86 (95% CI: 0.30–2.46) Adjusted OR for abnormal pregnancy/spontaneous abortion for women age 15–19 vs. age 25–44: 1.05 (95% CI: 0.54–2.06) Normal Pregnancy: Adjusted OR for normal pregnancy for women age 15–19 vs. age 20–24: 1.28 (95% CI: 0.89–1.86) Adjusted OR for normal pregnancy for women age 15–19 vs. age 25–44: 1.42 (95% CI: 1.13–1.78)	Large database Able to look at types of pregnancies Multivariate analysis, adjusted for age, intrauterine device type, health care provider specialty, region and year of IUD insertion Excluded women without 12 months of continuous insurance coverage	Limited by diagnostic coding; potential underreporting of outcomes not captured in database Did not include parity as potential confounder No information on whether those not included in analysis were different from sample	II-2, fair
Luukkainen, 1983 [16], and Allonen, 1984 [17]  Denmark, Finland and Sweden Population Council, International Development Research Centre of Canada, Ford Foundation, Rockefeller Foundation	Prospective cohort (data from RCT comparing two Cu-IUDs) 5 years, yearly visits	Women presenting for IUD insertion, randomized to Nova-T (n=918) or Cu T (n=947) inserted postmenstrual or postabortion (n=322) Nova-T: Age ≤19: n=75 Age 20–24: n=253 Age>24: n=590	Nova-T (n=918)	60-month cumulative net pregnancy rates per 100 acceptors	60-month cumulative pregnancy rates per 100 NovaT acceptors: Age <25: 3.0%; Pearl Index 1.3 Age 25–29: 2.6%; Pearl Index 0.9 Age 30–34: 1.1%; Pearl Index 0.4 Age 35+ years: 0.8%; Pearl Index 0.3 Pregnancy rate d ecreased with age for both devices combined in analysis (9) (adjusted RR 0.90 per year of age, p=.001) (5)	Long follow-up Multicenter trial Multiple providers Low loss to follow-up over 5 years (13.1%) Life Table regression analysis, including screening for parity as potential confounder and included IUD type and country in final model	Not powered to detect differences between age groups Infrequent follow-up after first year (every 12 months) may have led to underreporting of some outcomes	II-2, fair
Nygren, 1981 [18]	Prospective cohort (data from RCT two IUDs) 3 years	Women presenting for IUD insertion, randomized to Nova-T (n=916) or Cu T inserted postmenstrual Nova T: Age <20 years old: n=~73 (~8%) Age 20–24 years: n=~257 (~28%) >24 years: n=~586 women (~64%)	Nova-T	36-month net cumulative pregnancy rates by age Number of pregnancies at 36 months	Pregnancy rates (number of pregnancies): Age <20: 1.5% (n=1) Age 20–24: 3.0% (n=7) Age 25–29: 2.1% (n=5) Age 30–34: 1.1% (n=2) Age>35: 0.8% (n=1)	Multicenter trial Multiple providers Women not seen after insertion were not included in study Low LTFU 11.4%	Graphical display of age and parity breakdown No statistical testing for age or parity comparisons reported	II-2, poor
Ravi, 2014 [21] United States American Academy of Family Physicians, NIH grant K23HD067247	Retrospective cohort Chart reviewed up to 6 months after insertion	All women age ≤35 with IUD insertion in an NYC-area FQHC network (n=684) Age <21: n=182 Age 21–35: n=502	LNG-IUD (n=487) Cu-IUD (n=196)	Pregnancy	One pregnancy reported among older age group (23-year-old woman) using Cu-IUD	Multiple sites within FQHC network Participants with follow-up had similar baseline characteristics as those without follow-up, except for IUD payment	Groups differed at baseline by race, ethnicity, parity, IUD payment and site of insertion All data from chart review; outcomes may be underestimated if women sought care from other sites High attrition	II-2, poor
Skajaa, 1990 [22] Denmark	Retrospective cohort 6 years Follow-up visit at 5 weeks, then annually	Women aged 14–47 who received IUD (n=1697) Age <20: n=98 Age 20–24: n=454 Age 25–29: n=506 Age 30–35: n=337 Age ≥35: n=260	Multiload Cu250 (n=717) Nova-T (n=938)	Removals due to pregnancy with IUD in place	Cumulative 6-year complication rate per 100 women for pregnancy (95% CI) Age <20: 10.8 (5.0–22.6) Age 20–24: 5.0 (3.0–8.3) Age 25–29: 3.9 (2.4–6.5) Age 30–34: 2.6 (1.3–5.5) Age ≥35: 0.9 (0.2–3.4) All: 3.7 (2.8–5.0)	Large sample size	Unclear follow-up rates and women-years Single site Cumulative rates for each outcome did not assess or adjust for potential	II-2, poor
Suhonen, 2004 [23] Finland, Sweden Source of support NR	RCT 12 months	Nulliparous women age 18–25 (median age 21 years) randomized to LNG-IUD or COCs (n=193) LNG-IUD: n=94 COC (30 mcg EE/ 150 mcg desogestrel): n=99	LNG-IUD	Pregnancy	No pregnancies reported in either group	Multiple sites Similar loss to follow-up: 19/94 (20.2%) attrition in IUD and 27/99 (27.3%) in COC group	Determination of adequate randomization not reported, potential confounders uncertain Few events, powered on anticipated continuation rates, mostly likely lacking in power for other outcomes	I, fair

EE, ethinyl estradiol; LNG-IUS, levonorgestrel intrauterine system; LTFU, long-term follow-up.