Elsevier

The Lancet

Volume 380, Issue 9837, 14–20 July 2012, Pages 149-156
The Lancet

Series
Contraception and health

https://doi.org/10.1016/S0140-6736(12)60609-6Get rights and content

Summary

Increasing contraceptive use in developing countries has cut the number of maternal deaths by 40% over the past 20 years, merely by reducing the number of unintended pregnancies. By preventing high-risk pregnancies, especially in women of high parities, and those that would have ended in unsafe abortion, increased contraceptive use has reduced the maternal mortality ratio—the risk of maternal death per 100 000 livebirths—by about 26% in little more than a decade. A further 30% of maternal deaths could be avoided by fulfilment of unmet need for contraception. The benefits of modern contraceptives to women's health, including non-contraceptive benefits of specific methods, outweigh the risks. Contraception can also improve perinatal outcomes and child survival, mainly by lengthening interpregnancy intervals. In developing countries, the risk of prematurity and low birthweight doubles when conception occurs within 6 months of a previous birth, and children born within 2 years of an elder sibling are 60% more likely to die in infancy than are those born more than 2 years after their sibling.

Introduction

The most substantial benefits of contraceptive use for the health and survival of women and children stem from reductions in the number of pregnancies, especially those that are a greater-than-average risk to maternal, perinatal, and child survival. These risks are associated with pregnancies at very young (<18 years) and old (>34 years) maternal ages, at high parities, and with short interpregnancy intervals, and with pregnancies that would have ended in unsafe abortion. We assess the effect of contraception on these demographic features of reproduction (appendix). We estimate that an increase in contraceptive use of 10 percentage points reduces fertility by 0·6 births per woman, decreases the proportion of all births to women with four or more children by 5 percentage points, reduces births to women aged 35 years or older by 1·5 percentage points, and lowers birth intervals of less than 2 years by 3·5 percentage points. We consider the effects of these factors on maternal, perinatal, and child health. The emphasis throughout is on countries of low and middle income. We summarise the evidence for the well-established non-contraceptive benefits and risks of specific contraceptive methods for women's health. Where appropriate, we have updated systematic reviews by doing another search with the same terms used in those reviews, with the addition of our own search terms, and analysed secondary data.

Key messages

  • Increases in contraceptive use account for about 75% of fertility decline in developing countries in the past six decades and have substantially reduced the proportion of pregnancies in women of high parity, which pose a greater-than-average risk to maternal survival

  • In 2008, contraceptive use averted over 250 000 maternal deaths worldwide by reducing unintended pregnancies, which is equivalent to 40% of the 355 000 maternal deaths that occurred that year

  • If all women in developing countries who want to avoid pregnancy use an effective contraceptive method, the number of maternal deaths would fall by a further 30%

  • Because of its effect on births to women of high parity and on the need to resort to unsafe abortion, contraception also reduces the risk of maternal death per pregnancy; each 1 percentage point increase in contraceptive use reduces the maternal mortality ratio by 4·8 deaths per 100 000 livebirths

  • Contraceptive use has the potential to improve perinatal outcomes and child survival by widening the interval between successive pregnancies; in rich and poor countries the risks of prematurity and low birthweight are substantially raised by short intervals, and in developing countries, risk of death in infancy (ages <1 year) would fall by 10%, and in ages 1–4 years by 21%, if all children were spaced by a gap of 2 years

  • The health benefits of specific contraceptive methods far outweigh the health risks, although minor side-effects result in high probabilities of discontinuation, particularly of hormonal methods

Section snippets

Maternal mortality measures and fertility

Maternal mortality risk is affected by the number and timing of pregnancies in a woman's reproductive lifespan, by the presence of comorbidities, and by obstetric care. The effect of these factors is quantifiable by four measures: the number of maternal deaths, the maternal mortality rate (MMRate), the maternal mortality ratio (MMRatio), and the lifetime risk of maternal death.

The MMRate is the yearly number of maternal deaths per 1000 women of childbearing age (15–49 years). The MMRatio has

Perinatal health

Conde-Agudelo and colleagues31 reported the results of a comprehensive systematic review and meta-analysis of observational studies investigating the association between interpregnancy interval and adverse perinatal outcomes. 67 studies whose results were adjusted for at least maternal age and socioeconomic status, including more than 11 million pregnancies, met the strict inclusion criteria. 26 of these studies provided data for meta-analyses, 16 provided data for preterm birth, ten for low

Infant and child mortality and health

Of the possible demographic effects on child health, birth spacing has been the main focus. A comprehensive analysis by Rutstein42 examined the effect of the length of time from the birth of the preceding child to the conception of the index child using pooled data for more than 1 million births from 52 Demographic and Health Surveys. A large number of demographic and socioeconomic factors were controlled through regressions. We show the key adjusted results in figure 4. For infants (children

Non-contraceptive health benefits and risks of specific methods

Compelling evidence exists for the overall health benefits of modern contraceptives exceeding the health risks for most women, and that the risks associated with use are less than are those of non-use.52 Although the contraceptive benefits of modern methods are broadly the same, the non-contraceptive benefits and risks are specific to each method.

The most prevalent method of contraception worldwide is surgical sterilisation. Female sterilisation (tubal sterilisation) and male sterilisation

Discussion

Contraception is unique among medical interventions in the breadth of its positive outcomes. Reproductive choice is one of the more fundamental human rights, and by freeing women from an incessant cycle of pregnancy, breastfeeding, and child care, contraception represents a huge step towards greater gender equality. The benefits to families of fewer children, in whom more resources can be invested, and the benefits to societies of reduced fertility and slowed population growth for social and

Search strategy and selection criteria

We searched Medline, Embase, Popline, the Cumulative Index to Nursing and Allied Health Literature (CINAHL), and Literatura Latino-Americana e do Caribe em Ciências da Saúde (LILACS) with a combination of words related to contraception or family planning, birth or pregnancy spacing, fertility, unintended pregnancy, adolescent pregnancy, high-risk pregnancy, abortion, maternal health, maternal mortality, perinatal health, infant health, infant mortality, child health, and child mortality,

References (69)

  • M Vessey et al.

    Factors affecting mortality in a large cohort study with special reference to oral contraceptive use

    Contraception

    (2010)
  • R Heffron et al.

    Use of hormonal contraceptives and risk of HIV-1 transmission: a prospective cohort study

    Lancet Infect Dis

    (2012)
  • AF Glasier et al.

    Amenorrhea associated with contraception-an international study on acceptability

    Contraception

    (2003)
  • MC Hogan et al.

    Maternal mortality for 181 countries, 1980–2008: a systematic analysis of progress towards Millennium Development Goal 5

    Lancet

    (2010)
  • MA Koenig et al.

    Maternal mortality in Matlab, Bangladesh, 1976–85

    Stud Fam Plann

    (1988)
  • J Bhatia

    Levels and causes of maternal mortality in southern India

    Stud Fam Plann

    (1993)
  • DW Wee et al.

    Pregnancy-related mortality in southern Nepal between 2001 and 2006: independent estimates from a prospective, population-based cohort and a direct sisterhood survey

    Am J Epidemiol

    (2010)
  • HK Atrash et al.

    Maternal mortality in the United States, 1979–1986

    Obstet Gynecol

    (1990)
  • J Cecatti et al.

    The associations between inter-pregnancy interval and maternal and neonatal outcomes in Brazil

    Matern Child Health J

    (2008)
  • AK Jain

    Measuring the effect of fertility decline on the maternal mortality ratio

    Stud Fam Plann

    (2011)
  • J Fortney

    The importance of family planning in reducing maternal mortality

    Stud Fam Plann

    (1987)
  • J Trussell et al.

    The potential impact of changes in fertility on infant, child and maternal mortality

    Stud Fam Plann

    (1984)
  • B Winikoff et al.

    Assessing the role of family planning in reducing maternal mortality

    Stud Fam Plann

    (1987)
  • F Fikree et al.

    Maternal mortality in different Pakistani sites: ratios, clinical causes and determinants

    Acta Obstet Gynecol Scand

    (1997)
  • M Garenne et al.

    Risk factors for maternal mortality: a case-control study in Dakar hospitals (Senegal)

    Afr J Reprod Health

    (1997)
  • MH Bouvier-Colle et al.

    Maternal mortality in West Africa: rates, causes and substandard care from a prospective survey

    Acta Obstet Gynecol Scand

    (2001)
  • A Conde-Agudelo et al.

    Maternal morbidity and mortality associated with interpregnancy interval: cross sectional study

    BMJ

    (2000)
  • S Singh et al.

    Unintended pregnancy: worldwide levels, trends and outcomes

    Stud Fam Plann

    (2010)
  • I Shah et al.

    New estimates and trends regarding unsafe abortion mortality

    Int J Gynaecol Obstet

    (2011)
  • Unsafe abortion. Global and regional estimates of the incidence of unsafe abortion and associated mortality in 2008

    (2011)
  • J Ross et al.

    Why aren't there more maternal deaths? A decomposition analysis

    Matern Child Health J

    (2012)
  • J Darroch et al.

    Estimating unintended pregnancies averted from couple-years of protection (CYP)

    (2011)
  • Trends in maternal mortality: 1990 to 2008

    (2010)
  • S Ahmed et al.

    Maternal deaths averted by contraceptive use: an analysis of 172 countries

    Lancet

    (2012)
  • Cited by (464)

    View all citing articles on Scopus
    View full text