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Adolescent Pregnancy, Birth, and Abortion Rates Across Countries: Levels and Recent Trends

      Abstract

      Purpose

      To examine pregnancy rates and outcomes (births and abortions) among 15- to 19-year olds and 10- to 14-year olds in all countries for which recent information could be obtained and to examine trends since the mid-1990s.

      Methods

      Information was obtained from countries' vital statistics reports and the United Nations Statistics Division for most countries in this study. Alternate sources of information were used if needed and available. We present estimates primarily for 2011 and compare them to estimates published for the mid-1990s.

      Results

      Among the 21 countries with complete statistics, the pregnancy rate among 15- to 19-year olds was the highest in the United States (57 pregnancies per 1,000 females) and the lowest rate was in Switzerland (8). Rates were higher in some former Soviet countries with incomplete statistics; they were the highest in Mexico and Sub-Saharan African countries with available information. Among countries with reliable evidence, the highest rate among 10- to 14-year olds was in Hungary. The proportion of teen pregnancies that ended in abortion ranged from 17% in Slovakia to 69% in Sweden. The proportion of pregnancies that ended in live births tended to be higher in countries with high teen pregnancy rates (p = .02). The pregnancy rate has declined since the mid-1990s in the majority of the 16 countries where trends could be assessed.

      Conclusions

      Despite recent declines, teen pregnancy rates remain high in many countries. Research on the planning status of these pregnancies and on factors that determine how teens resolve their pregnancies could further inform programs and policies.

      Keywords

      Implications and Contribution
      Adolescent pregnancy rates declined since the mid-1990s in most developed countries with reliable trend data, but the rate remains exceptionally high in the United States. Rates are even higher in Sub-Saharan Africa and in some former Soviet countries where data quality is variable. The proportion of pregnancies ending in abortion varies widely across countries.
      The causes and consequences of teen pregnancies have been the topic of much research, policy and program discussion, and debate. Some studies have suggested that teen pregnancies compromise women's educational prospects and economic opportunities [
      UNFPA
      Motherhood in childhood: Facing the challenge of adolescent pregnancy: The State of World Population 2013.
      ,

      World Health Organization. Preventing early pregnancy and poor reproductive outcomes among adolescents in developing countries. Available at: http://www.who.int/reproductivehealth/publications/adolescence/9789241502214/en/. Accessed January 27, 2014.

      ,
      National Research Council
      Growing up global: The changing transitions to adulthood in developing countries.
      ], and other work indicates that teen pregnancies are a marker of such conditions, rather than an underlying cause of them [
      • Coyne C.A.
      • D’Onofrio B.M.
      Some (but not much) progress toward understanding teenage childbearing: A review of research from the past decade.
      ,
      • Korenman S.
      • Fales S.
      The socioeconomic effects of teenage childbearing: A review of the recent literature.
      ]. There does appear to be consensus, however, that teen pregnancies are associated with poor social and economic conditions and prospects.
      A substantial proportion of teen births are intended in developing countries where many women still marry early [
      • Kothari M.T.
      • Wang S.
      • Head S.
      • et al.
      Trends in adolescent reproductive and sexual behaviors.
      ]. However, even intended pregnancies to young women in low-resource settings are of policy and public health relevance because of the risks associated with them. The risk of death associated with pregnancy is about a third higher among 15- to 19-year olds than among 20- to 24-year olds [
      • Nove A.
      • Matthews Z.
      • Neal S.
      • et al.
      Maternal mortality in adolescents compared with women of other ages: Evidence from 144 countries.
      ]. It appears that young adolescents are also more likely to experience obstructed labor, fistula, and premature delivery and to give birth to low birth weight babies than older women [
      UNFPA
      Motherhood in childhood: Facing the challenge of adolescent pregnancy: The State of World Population 2013.
      ].
      Country-specific estimates of pregnancy, birth, and abortion levels among adolescents can motivate policy and programmatic responses to teen pregnancies and help monitor progress toward reducing their incidence. Countries with low levels of adolescent pregnancy might serve as references or models for efforts to reduce levels elsewhere. Even where incidence is low, data on teen pregnancies can highlight remaining unmet needs for information and services to help adolescents prevent unintended pregnancies.
      Earlier reviews of adolescent pregnancy and childbearing rates across countries covered trends up to the mid-1990s and found that these events were becoming less common in the majority of countries for which evidence was available [
      • Singh S.
      • Darroch J.E.
      Adolescent pregnancy and childbearing: Levels and trends in developed countries.
      ,
      • Singh S.
      Adolescent childbearing in developing countries: A global review.
      ]. At that time, the teen pregnancy rate in the United States was higher than in any other developed country for which estimates were available except Russia. Regional estimates for the developing world indicated that adolescent birth rates were especially high in Sub-Saharan Africa [
      National Research Council
      Growing up global: The changing transitions to adulthood in developing countries.
      ].
      We examine pregnancy incidence among adolescents (15–19 years old) and young adolescents (10–14 years old) in all developed and developing countries for which recent data on teen births and abortions could be obtained. We examine abortion
      Unless otherwise indicated, “abortion” refers to induced abortions throughout this report.
      1Unless otherwise indicated, “abortion” refers to induced abortions throughout this report.
      and birth rates and the proportion of pregnancies that end in abortion in these countries and the correlation between adolescent pregnancy rates and the proportion of pregnancies that end in abortion. We examine trends in these rates since the mid-1990s through 2008–2011 where data allow.

      Methods

      To estimate teen
      The terms “teens” and “adolescents” are used interchangeably in these analyses to refer to 15- to 19-year olds.
      and early adolescent pregnancy rates, we require data on numbers of births, abortions, and females 10–14 and 15–19 years old. For most countries, information on all three components was obtained, in descending order of preference, from countries' published vital statistics reports, compilations of these reports in the United Nations (UN) Statistics Division's Demographic Yearbook [], the Transformative Monitoring for Enhanced Equity Database maintained by the United Nations Children's Fund [

      UNICEF. The Transformative Monitoring for Enhanced Equity (TransMonEE) database 2013. Available at: http://www.transmonee.org/. Accessed September 1, 2013.

      ], or the UN Population Division's population projections [

      United Nations Population Division, Population estimates and projections section. World population prospects: The 2012 revision. Available at: http://esa.un.org/unpd/wpp/index.htm. Accessed January 16, 2014.

      ]. The data sources used for each component in each country are presented in Appendix Table 1.
      Birth data are generally complete, but the collection and evaluation of abortion data and estimation of miscarriages merit additional discussion. Abortion reports in the sources previously mentioned include only procedures that were performed within the bounds of the law. In countries with liberal abortion laws, nearly all, if not all, abortions are legal.
      Countries with highly restrictive laws and official reports of legal abortions performed are not included in this review because legal abortions account for a very small proportion of all procedures done in those countries.
      However, abortion statistics are not complete for all countries, even for legal abortions. The quality of abortion statistics varies across countries and depends on a number of factors including whether abortion reporting is voluntary or required by law, whether all types of induced abortion procedures are required to be reported, whether there are consequences for failure to report abortions, such as lack of reimbursement for services rendered, whether there are financial disincentives to reporting abortions, such as tax obligations associated with abortion performed, and whether reporting systems have complete coverage of abortions provided in the private sector. The completeness of reporting can also change over time if circumstances that influence reporting change. In this analysis, we categorize countries into three groups:
      • 1.
        Those with liberal laws whose official abortion statistics are deemed complete, that is, likely to include at least 90% of all abortions.
      • 2.
        Those with liberal abortion laws and incomplete abortion statistics, or for which completeness of reports is uncertain.
      • 3.
        Those with restrictive abortion laws, for which abortion estimates are available from country studies rather than official statistics.
      Classifications of the completeness of abortion reports were based on expert assessments obtained for a recent study of abortion incidence [
      • Sedgh G.
      • Singh S.
      • Henshaw S.K.
      • et al.
      Legal abortion worldwide in 2008: Levels and recent trends.
      ].
      The study on abortion incidence referenced here includes more countries than the present study because data on age-specific abortion incidence is needed to compute teen pregnancy rates, and age-specific data are not available for all countries with overall abortion estimates.
      For that undertaking, input was sought from agencies involved in data collection and from local experts, primarily demographers and other researchers, on the completeness of official reports. In addition, comparisons with estimates from alternate sources, such as surveys of women, were made when such sources were available.
      Additional details on the countries with incomplete statistics and those with restrictive abortion laws follow.

      Countries with incomplete statistics

      For countries with incomplete abortion statistics, pregnancy rates and the proportions of pregnancies that end in abortion presented here are lower than the true values because the numbers of abortions are undercounted. Such estimates are nevertheless useful because they indicate the minimum levels of both measures in these countries. For a few countries lacking official abortion reports with sufficient coverage, we used abortion estimates from alternate sources.
      For the United States, we combined estimates of abortion incidence based on a 2010 census of abortion providers [
      • Jones R.K.
      • Jerman J.
      Abortion incidence and service availability in the United States, 2011.
      ] with information on the age distribution of abortions compiled annually by the Centers for Disease Control and Prevention [

      Pazol K, Creanga AA, Burley KD, et al. Abortion Surveillance – United States, 2010. Morbidity and Mortality Weekly Report, Division of Reproductive Health, CDC. Available at: http://www.cdc.gov/mmwr/preview/mmwrhtml/ss6208a1.htm?s_cid=ss6208a1_w. Accessed August, 15 2014.

      ].
      Centers for Disease Control and Prevention estimates of the age distribution of women who have abortions are based on abortion reports that are deemed to include about 70% of all abortions done in the United States.
      Because the census is deemed to include more than 90% of abortions, the resulting estimates for the United States are classified as complete.
      Data on the level of underreporting in each country are limited, and we did not attempt to quantify the level of underreporting beyond ascertaining whether reports included at least 90% of all abortions nor did we adjust statistics to account for possible levels of underreporting.

      Countries with restrictive abortion laws

      Reliable national estimates of age-specific incidence of abortion are available for only five countries with restrictive laws, all in Sub-Saharan Africa and Latin America: Burkina Faso, Ethiopia, Kenya, Malawi, and Mexico.
      In Mexico, less than 10% of women of reproductive age live in the Federal District where abortion is permitted on demand up to 12 weeks of gestation. Although the conditions under which abortion is legally allowed in Ethiopia were recently broadened, it is still counted among countries with restrictive laws.
      These abortion estimates are derived from country studies [
      • Sedgh G.
      • Rossier C.
      • Kaboré I.
      • et al.
      Estimating abortion incidence in Burkina Faso using two methodologies.
      ,
      • Singh S.
      • Fetters T.
      • Gebreselassie H.
      • et al.
      The estimated incidence of induced abortion in Ethiopia, 2008.
      ,
      • Levandowski B.A.
      • Mhango C.
      • Kuchingale E.
      • et al.
      The incidence of induced abortion in Malawi.
      ,
      • Juarez F.
      • Singh S.
      Incidence of induced abortion by age and state, Mexico, 2009: New estimates using a modified methodology.
      ,

      Mohamed SF, Izugbara C, Moore AM, et al. The incidence of induced abortion in Kenya. Manuscript submitted to the British Journal of Obstetrics and Gynaecology.

      ]. Abortion estimates in these countries include both legal and illegal abortions.

      Miscarriages

      The incidence of miscarriage was estimated on the basis of clinical studies of pregnancy loss by gestational age, which indicate that recognized miscarriages at five or more weeks of gestation are equal to approximately 20% of births plus 10% of induced abortions [
      • Bongaarts J.
      • Potter R.G.
      Fertility, biology, and behavior: An analysis of the proximate determinants.
      ,
      • Leridon H.
      Human fertility: The basic components.
      ]. Findings from recent surveys of women in the United States support these model-based estimates [
      • Finer L.B.
      • Henshaw S.K.
      Disparities in rates of unintended pregnancy in the United States, 1994 and 2001.
      ].
      Birth rates are compared across all countries covered in this review regardless of whether the abortion and pregnancy rates are complete because births are not as vulnerable to underreporting as abortions.
      Adolescent pregnancy, birth, and abortion rates are the number of events per 1,000 females 15–19 years old. The rates for young adolescents are calculated as the number of events per 1,000 females 10–14 years old. Rates among young adolescents would likely be higher if they could be computed for 13- to 14-year olds, to whom most of these events likely occur, but population estimates for this 2-year age group are not available for many countries. For all pregnancies, the adolescent's age is measured at the time of the pregnancy outcome. Confidence intervals are not presented because vital statistics on live births and populations are not considered estimates with uncertainty, but true population values.
      The majority of findings presented here are for developed countries according to the UN classification of countries [

      United Nations Statistics Division. Composition of macro geographical (continental) regions, geographical sub-regions, and selected economic and other groupings. Available at: http://unstats.un.org/unsd/methods/m49/m49regin.htm. Accessed August 1, 2014.

      ].
      Developing countries covered in this report include Armenia, Azerbaijan, Georgia, Kazakhstan, Kyrgystan, Hong Kong, Israel, and Mongolia, all of which have liberal abortion laws, and Burkina Faso, Ethiopia, Kenya, Malawi, and Mexico where abortion laws are restrictive.
      We primarily present estimates for 2011, the most recent year for which information is available for most countries. If information was not available for 2011, we sought estimates for an earlier time period but not earlier than 2008. The only exception is Kenya, for which we report an estimate for 2012 because that is the only year for which relevant information is available.
      We examine trends in countries for which estimates for the mid-1990s were previously published [
      • Singh S.
      • Darroch J.E.
      Adolescent pregnancy and childbearing: Levels and trends in developed countries.
      ], if estimates are deemed to be sufficiently complete in both periods. The estimates for that period were similarly made across all possible countries and classified by completeness of reports. The previously published data included only births and abortions; we estimated numbers of miscarriages in the mid-1990s to render the pregnancy estimates comparable with those for 2011. Trends in teen pregnancy rates since the mid-1990s are presented both as the average annual change in absolute rate points and the annualized
      Calculated, for example, as (Rate2011/Rate1995)ˆ(1/[2011 − 1995]) − 1.
      percentage change in each country. Both measures are useful because the absolute point change can be large if the baseline rate is high, whereas the percentage change controls for differences in the baseline rate.
      To examine the correlation between teen pregnancy rates and the proportion of pregnancies that ended in abortion in 2011, we used bivariate analyses of two continuous variables to estimate the correlation coefficient and associated p value.

      Results

      Among the 21 countries with liberal abortion laws and complete teen pregnancy estimates for 2008–2011, the rate was the highest in the United States (57 pregnancies per 1,000 adolescents in 2010), followed by New Zealand (51) and England and Wales (47) (Table 1). The lowest teen pregnancy rate was in Switzerland (8), followed by the Netherlands (14), Singapore (14), and Slovenia (14). Among countries with incomplete estimates, rates were high in Azerbaijan (67), Georgia (62), and Romania (61). Adolescent pregnancy rates were far higher in Mexico and the Sub-Saharan African countries than in any other countries in this review, ranging from 121 (Ethiopia) to 187 (Burkina Faso).
      Table 1Adolescent birth, abortion, and pregnancy rates and percentage of pregnancies ending in abortion among females 15–19 years old, 2011 or most recent prior year
      CountryYearNumber of pregnanciesRate per 1,000 females 15–19 years oldPregnancies that end in abortion (%)
      Pregnancies
      Pregnancies are composed of miscarriages (not shown), abortions, and births.
      AbortionsBirths
      Countries with complete abortion statistics
       Belgium20096,8002181038
       Denmark20113,6002114567
       England and Wales201181,00047202142
       Estonia20111,40043191943
       Finland20113,7002313855
       France201147,9002515761
       Hungary201111,60038161841
       Iceland201130030151151
       Israel20116,8002381332
       Netherlands20086,900147550
       New Zealand20117,90051182636
       Norway20113,5002313756
       Portugal20116,8002581333
       Scotland20117,40046172337
       Singapore20111,800148554
       Slovakia20115,9003362217
       Slovenia2009700147548
       Spain201128,00026131050
       Sweden20109,0002920669
       Switzerland20111,70085259
       United States2010614,00057153426
      Countries with incomplete official abortion statistics
       Albania20093,400231184
       Armenia
      Pregnanices are calculated using birth, abortion, and miscarriage rates with population estimates, and they include births and abortions to all females under 20 years old.
      20114,2863752613
       Azerbaijan
      Pregnanices are calculated using birth, abortion, and miscarriage rates with population estimates, and they include births and abortions to all females under 20 years old.
      201129,268674543
       Belarus200813,20039122230
       Canada201129,90028121342
       Croatia20112,1001731217
       Czech Republic20115,8002071133
       Georgia20119,90062114217
       Germany201124,20092523
       Hong Kong20092,100105451
       Japan201038,500137453
       Kazakhstan
      Pregnanices are calculated using birth, abortion, and miscarriage rates with population estimates, and they include births and abortions to all females under 20 years old.
      201125,9154042910
       Kyrgyzstan
      Pregnanices are calculated using birth, abortion, and miscarriage rates with population estimates, and they include births and abortions to all females under 20 years old.
      201116,1305764111
       Latvia
      Pregnanices are calculated using birth, abortion, and miscarriage rates with population estimates, and they include births and abortions to all females under 20 years old.
      20111,6312891533
       Lithuania20112,3001941321
       Macedonia
      Pregnanices are calculated using birth, abortion, and miscarriage rates with population estimates, and they include births and abortions to all females under 20 years old.
      20111,8162531811
       Moldova20106,3004392721
       Mongolia20084,4002951917
       Montenegro
      Pregnanices are calculated using birth, abortion, and miscarriage rates with population estimates, and they include births and abortions to all females under 20 years old.
      2011397191146
       Romania201134,70061173528
       Russian Federation2011197,10049162634
       Serbia
      Pregnanices are calculated using birth, abortion, and miscarriage rates with population estimates, and they include births and abortions to all females under 20 years old.
      20115,0102631911
       Ukraine201172,3004492821
      Countries with abortion estimates from country studies
      Abortion rates are based on country studies using an indirect estimation technique.
       Burkina Faso2008147,7001873012816
       Ethiopia2008520,70012111919
       Kenya2012348,9001743811122
       Malawi2009100,3001542110914
       Mexico2009677,000130446834
      Additional notes:
      Albania: Abortion estimates are from a nationally representative survey of women.
      France: Population estimate is for the start of the year.
      Germany: Includes abortions for ≤17-year olds only.
      a Pregnancies are composed of miscarriages (not shown), abortions, and births.
      b Pregnanices are calculated using birth, abortion, and miscarriage rates with population estimates, and they include births and abortions to all females under 20 years old.
      c Abortion rates are based on country studies using an indirect estimation technique.
      Because of a high teen pregnancy rate and large population, the estimated annual number of teen pregnancies was far higher in the United States (614,000) than any other country in this review. The number of teen pregnancies was also high in Mexico (677,000) and Ethiopia (521,000).
      The birth rates in the countries with complete pregnancy estimates ranged from 2 (Switzerland) to 34 (the United States). However, teen birth rates can be fairly compared across a broader range of countries because these statistics are less prone to underreporting than are abortion rates. Among all 49 countries reviewed here, the rates were the highest by far in countries in Sub-Saharan Africa. The rate exceeded 90 in all four countries represented from this region and was the highest in Burkina Faso (128). Outside Sub-Saharan Africa, the highest teen birth rate was in Mexico (68), followed by Azerbaijan (54). Among the Northern, Western, and Southern European countries, the birth rate was the highest in Scotland (23) and England and Wales (21).
      The highest adolescent abortion rate among countries with complete abortion records was in England and Wales (20) and Sweden (20). It was 15 in the United States. In about half of the countries, the rate was between 8 and 17. The teen abortion rate was the lowest in Switzerland (5). In Mexico and the countries in Sub-Saharan Africa, where abortion is largely illegal, the adolescent abortion rate ranged from 11 (Ethiopia) to 44 (Mexico).
      The proportion of teen pregnancies that ended in abortion varied widely across the countries with complete estimates, from 17% in Slovakia to 69% in Sweden. In half of the countries, 35%–55% of pregnancies ended in abortion. This statistic was not calculated for the countries with incomplete abortion statistics. In Mexico and the countries in Sub-Saharan Africa, the proportion ranged from 9% in Ethiopia to 34% in Mexico.
      Among countries whose reports are deemed to include at least 90% of all abortions done, the reports might still omit up to 10% of all abortions. If 10% of abortions were missing from these reports, the true percentage of pregnancies that ended in abortion would be 1.5%–2.4% points higher than indicated in our results (not shown).
      For the countries with complete statistics, there is an inverse correlation between the pregnancy rate and the proportion of pregnancies ending in abortion (ρ = −.49; p = .02; Figure 1). In countries with high teen pregnancy rates, a smaller proportion of those pregnancies ended in abortion. As a result, the spread in birth rates is even greater than the already large spread in pregnancy rates. For example, the U.S. teen pregnancy rate is about seven times that of Switzerland, but the U.S. birth rate is 15 times that of Switzerland.
      Figure thumbnail gr1
      Figure 1Percentage of teen pregnancies ending in abortion is inversely correlated with teen pregnancy rate (ρ = −.53). BEL = Belgium; DEN = Denmark; ENG = England and Wales; EST = Estonia; FIN = Finland; FRA = France; HUN = Hungary; ICE = Iceland; ISR = Israel; NET = The Netherlands; NOR = Norway; NZ = New Zealand; POR = Portugal; SCO = Scotland; SIN = Singapore; SPA = Spain; SVK = Slovakia; SVN = Slovenia; SWE = Sweden; SWI = Switzerland; USA = United States.
      Pregnancy, birth, and abortion rates among young adolescents (10–14 years old) are far lower than among 15- to 19-year olds (Table 2). Of the 23 countries for which birth rates to 10- to 14-year olds are presented, the highest was in Romania (1.40), followed by the United States (.45). In the majority of countries, there were fewer than .20 births per 1,000 10- to 14-year-old girls. Of the 11 countries with complete estimates of young adolescent pregnancy rates, the lowest was in Switzerland (.09) and the highest was in Hungary (1.19 pregnancies per 1,000 females 10–14 years old) and the United States (1.08). The rate was even higher in Romania (2.64) where it is likely underestimated. Estimates for this age group are not available from the studies conducted in countries with restrictive abortion laws. The percentage of pregnancies to girls in this age group that ended in abortion was the lowest in Slovakia (22%) and otherwise ranged from 46% in the United States to 87% in Sweden. Generally, a higher proportion of pregnancies to 10- to 14-year olds ended in abortion compared with the proportion among 15- to 19-year olds.
      Table 2Adolescent birth, abortion, and pregnancy rates and percentage of pregnancies ending in abortion among females 10–14 years old, 2011 or most recent prior year
      CountryYearRate per 1,000 females 10–14 years oldPregnancies that end in abortion (%)
      Pregnancies
      Pregnancies are composed of miscarriages (not shown), abortions, and births.
      AbortionsBirths
      Countries with complete abortion statistics
       Estonia2012.27.21.0477
       Hungary20111.19.71.3460
       New Zealand2011.73.48.1765
       Portugal2011.59.30.2151
       Singapore2011.22.14.0663
       Slovakia2011.50.13.3026
       Slovenia2009.12.09.0271
       Spain2011.64.43.1467
       Sweden2010.91.79.0387
       Switzerland2010.09.07.0174
       United States20101.08.49.4546
      Countries with incomplete official abortion statistics
       Belarus2008.22.14.0662
       Croatia2011.12.03.0729
       Czech Republic2010.27.18.0764
       Georgia2008.26.03.1912
       Hong Kong2009.23.15.0565
       Japan2010.18.14.0280
       Latvia2010.25.13.0953
       Lithuania2011.12.03.0824
       Moldova2010.21.10.0849
       Romania20112.64.871.4033
       Russian Federation2011.33.18.1155
       Serbia2010.46.07.3214
      a Pregnancies are composed of miscarriages (not shown), abortions, and births.

      Trends

      The teen pregnancy rate declined in the majority of the 16 countries with complete estimates in both the mid-1990s and 2011 (Figure 2; see also Appendix Table 2 for pregnancy, birth, and abortion rates in the mid-1990s). The steepest annualized percentage change occurred in Estonia (4% per year). The decline might have been steeper in Russia and some other former Soviet countries, but incomplete abortion reports preclude an assessment of trends in these countries. The steepest average annual point change in the rate was in the United States (2.9 points per year, on average) where the rate was the highest in 1996. The teen pregnancy rate increased in Belgium and Sweden. However, current rates in these countries are still fairly low, at 21 and 29, respectively.
      Figure thumbnail gr2
      Figure 2Changes in adolescent pregnancy rates, 1995–2011. See and for reference years.
      In most countries, the birth rate declined more steeply than the abortion rate. Exceptions are Hungary, Slovakia, and the United States where the abortion rate declined more steeply than the birth rate. In England and Wales, Finland, the Netherlands, Scotland, and Sweden, the teen abortion rate increased, whereas the teen birth rate declined.

      Discussion

      Although age-specific birth and abortion rates are periodically compiled across countries, this analysis represents the first known assessment of teen pregnancy rates, including births, abortions, and miscarriages, across a span of countries, and examination of trends since the mid-1990s across countries. In addition, this is the first to include teen pregnancy estimates for some countries with restrictive abortion laws.
      We found that, despite a considerable decline in recent decades, the highest teen pregnancy rate in the developed world outside the former Soviet bloc is still in the United States, and the highest rates in Europe outside the former Soviet bloc are in England and Wales and Scotland. As in the 1980s and early 1990s, pregnancy rates continued to fall in the majority of countries with trend data.
      This review is subject to some limitations. It only includes countries for which estimates of both births and abortions are available. Rates and trends could be different in countries that are not included in this review.
      Age-specific pregnancy rates for narrower age groups would serve to more precisely identify those teens with high pregnancy rates. For example, in the United States and the United Kingdom, the pregnancy rate is higher among 18- to 19-year olds than among 15- to 17-year olds [
      • Kost K.
      • Henshaw S.
      U.S. teenage pregnancies, births and abortions, 2010: National and state trends by age, race and ethnicity.
      ,
      • Wilkinson P.
      • French R.
      • Kane R.
      • et al.
      Teenage conceptions, abortions, and births in England, 1994-2003, and the national teenage pregnancy strategy.
      ].
      Trends are not always monotonic. In Canada, a more detailed review of data indicated that the teen pregnancy rate leveled off in 2006 after a period of decline [
      • Mckay A.
      Trends in Canadian national and provincial/territorial teen pregnancy rates: 2001-2010.
      ]; in Sweden, the rate seems to have stabilized since about 2002, after a decade-long upward trend [
      • McKay A.
      • Barrett M.
      Trends in teen pregnancy from 1996-2006: A comparison of Canada, Sweden, U.S.A. and England/Wales.
      ]; and in the United States, the pace of decline has been increasing [
      • Kost K.
      • Henshaw S.
      U.S. teenage pregnancies, births and abortions, 2010: National and state trends by age, race and ethnicity.
      ].
      Not surprisingly, adolescent pregnancy and birth rates are higher in Mexico and the countries in Sub-Saharan Africa than in the other countries in this review. In these regions, where norms often include early age at marriage and early start of childbearing, a larger proportion of pregnancies to adolescents are likely to be intended than in developed countries. For example, in Sub-Saharan Africa as a whole, only about 35% of pregnancies to 15- to 19-year olds in 2007 were unintended [
      • Biddlecom A.E.
      • Singh S.
      • Bankole A.
      • et al.
      Protecting the next generation in Sub-Saharan Africa: Learning from adolescents to prevent HIV and unintended pregnancy.
      ]. The planning status of pregnancies to teens is not systematically collected across developed countries, but in the United States, it is estimated that 82% of pregnancies to teens are unintended [
      • Finer L.B.
      • Zolna M.R.
      Shifts in intended and unintended pregnancies in the United States, 2001-2008.
      ].
      This is a descriptive study, not an inferential one, and we did not examine the factors that explain the differences across countries or trends over time. However, much research has been directed at understanding the possible drivers of teen pregnancy rates across populations. The most important immediate determinants of pregnancy incidence are sexual activity and contraceptive nonuse. Evidence indicates that, across industrialized countries, differences exist in contraceptive prevalence among adolescents, more so than in the level of sexual activity [
      • Mckay A.
      Trends in Canadian national and provincial/territorial teen pregnancy rates: 2001-2010.
      ,
      • Santelli J.
      • Sandfort T.
      • Orr M.
      Transnational comparisons of adolescent contraceptive use: What can we learn from these comparisons?.
      ,
      • Santelli J.S.
      • Melnikas A.J.
      Teen fertility in transition: Recent and historic trends in the United States.
      ]. Method mix and the effectiveness of the methods commonly used likely also influence differences in unintended pregnancy rates among teens across populations.
      Among the more distal determinants of teen pregnancy rates are social, economic, and cultural factors. Evidence suggests that the level of national wealth, the pace of economic development, and the magnitude of income inequality within countries are all associated with differences in teen birth rates between countries [
      • Santelli J.S.
      • Sharma V.
      • Viner R.
      Inequality, national wealth, economic development and global trends in teenage birth rates, 1990-2010.
      ]. The level of acceptance of adolescent sexuality and the social expectation that teens will responsibly use contraception have also been linked to levels of contraceptive use [
      • Schalet A.
      Not under my roof: Parents, teens and the culture of sex.
      ]. Recent evidence from Europe indicates that the provision of free or subsidized contraceptives is associated with relatively low pregnancy and birth rates [
      • Part K.
      • Moreau C.
      • Donati S.
      • et al.
      Teenage pregnancies in the European Union in the context of legislation and youth sexual and reproductive health services.
      ].
      Studies have more frequently examined the relationship among social, economic, and cultural factors and differences in teen pregnancy rates within countries. In the United Kingdom and the United States, for example, teen pregnancy rates are higher in the most socioeconomically disadvantaged groups [
      • Kost K.
      • Henshaw S.
      U.S. teenage pregnancies, births and abortions, 2010: National and state trends by age, race and ethnicity.
      ,
      • Wilkinson P.
      • French R.
      • Kane R.
      • et al.
      Teenage conceptions, abortions, and births in England, 1994-2003, and the national teenage pregnancy strategy.
      ,
      • Humby P.
      An analysis of under 18 conceptions and their links to measures of deprivation, England and Wales, 2008-10.
      ]. In the United States, the pregnancy rate is 100 among black teenagers and 38 among white teens (a rate that is still high for a developed country),
      Rates are for 2008.
      although this differential has decreased with time [
      • Ventura S.J.
      • Curtin S.C.
      • Abma J.C.
      • Henshaw S.K.
      Estimated pregnancy rates and rates of pregnancy outcomes for the United States, 1990-2008.
      ]. Qualitative research in the United Kingdom points to poor material circumstances, unhappiness at home or at school, and low expectations for the future as factors associated with high teen pregnancy rates [
      • Harden A.
      • Brunton G.
      • Fletcher A.
      • et al.
      Teenage pregnancy and social disadvantage: Systematic review integrating controlled trials and qualitative studies.
      ].
      At the other end of the spectrum, the very low teen pregnancy rate in Switzerland exists in the context of long-established sex education programs, widespread expectation that sexually active teens will use contraception, free family planning services and low-cost emergency contraception [
      • Narring F.
      • Yaron M.
      Adolescent pregnancy in Switzerland.
      ]. But even in Switzerland, statistics indicate that teen pregnancy rates vary with levels of education and cultural background of adolescent girls.
      Teen birth rates are high in many Eastern Europe and Central Asian countries. These high rates have been attributed to a number of barriers to access to contraception. In some former Soviet countries, females under 18 years old cannot access sexual and reproductive health services without a parent's consent [
      • Narring F.
      • Yaron M.
      Adolescent pregnancy in Switzerland.
      ].Other barriers noted in situational analyses include the high cost of supplies, prescription requirements for some methods, limited numbers of outlets from which to obtain contraceptive supplies, lack of sexuality education programs (and poor quality of programs where they do exist), and cultural norms that limit the use of contraception [
      UNFPA Eastern Europe and Central Asia Regional Office
      Adolescent pregnancy in Eastern Europe and Central Asia.
      ,
      ASTRA Network
      Sexual and reproductive health and rights of adolescents in Central and Eastern Europe and Balkan countries.
      ].
      The same proximate and distal factors that help explain differences in teen pregnancy rates across countries at one point in time have likely also contributed to trends in teen pregnancy rates over time. Relatively small downward trends in the prevalence of adolescent sexual activity and more substantial upward trends in contraceptive prevalence have been documented in the United States [
      • Santelli J.S.
      • Melnikas A.J.
      Teen fertility in transition: Recent and historic trends in the United States.
      ] and Canada [
      • Mckay A.
      Trends in Canadian national and provincial/territorial teen pregnancy rates: 2001-2010.
      ].
      We found that the proportion of teen pregnancies that end in abortion varies widely across countries with liberal abortion laws. The inverse association between the pregnancy rate and the proportion of pregnancies that end in abortion might reflect that a greater proportion of pregnancies are planned where rates are high. Alternately, it could suggest that the constellation of forces that make it hard for adolescents to prevent teen pregnancies (such as limited access to sexual and reproductive health services including family planning) also limit their ability to terminate unplanned pregnancies.
      Additional research would help us better understand circumstances that can lead to teen pregnancies and how these circumstances can be influenced. Examination of the factors that influence whether an adolescent who gets pregnant will seek an abortion or have a child can also inform how adolescents can be supported in the face of a pregnancy. Moreover, further research to help disentangle the factors that are causally associated with unplanned teen pregnancies from the factors that are simply correlated with such pregnancies can inform interventions aimed at helping adolescent girls avoid unintended pregnancy and instead take advantage of other opportunities before them.

      Acknowledgments

      The funders played no role in the design or conduct of the study, the collection, management, analysis, or interpretation of the data, or the preparation, review, or approval of the article. The authors thank Heather Boonstra for her valuable feedback on the article and to Alyssa Tartaglione for her help preparing the article for submission. Preliminary findings from this undertaking were presented at the annual meeting of the American Public Health Association in Boston, MA, in November 2013 and the European Population Conference in Budapest, Hungary, in June 2014. G.S. and L.B.F. led the conceptualization of this undertaking, with input from S.S. and A.B. G.S. oversaw data collection, led the interpretation of findings, and drafted the article. L.B.F. conducted portions of the data analysis and revised portions of the article. L.B.F., A.B., and S.S. provided substantive input during data collection and interpretation of findings and reviewed drafts of the article. M.A.E. collected and managed the data, helped prepare tables, and reviewed drafts of the article. All authors had access to all the data in the study and can take responsibility for the integrity of the data and the accuracy of the analysis.

      Funding Sources

      This research was funded by the Centers for Disease Control and Prevention through a cooperative agreement between the  Office of Population Affairs at the U.S. Department of Health and Human Services , and the Guttmacher Institute (Cooperating Agreement # 1-FPRPA006050-01-00) and by a grant from the Dutch Ministry of Foreign Affairs (Grant # 24590 ).

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