Advertisement

Contraceptive efficacy of lactational amenorrhea in urban Chilean women

  • S. Díaz
    Affiliations
    Instituto Chileno de Medicina Reproductiva Consultorio de Planificación Familiar J.V. Lastarria 29, Depto. 101 Santiago, Chile

    Laboratorio de Endocrinología, Facultad Ciencias Biológicas Facultad de Matemáticas, P. Universidad Católica de Chile Chile
    Search for articles by this author
  • R. Aravena
    Affiliations
    Departamento de Probabilidad y Estadística, Facultad de Matemáticas, P. Universidad Católica de Chile Chile
    Search for articles by this author
  • H. Cárdenas
    Affiliations
    Instituto Chileno de Medicina Reproductiva Consultorio de Planificación Familiar J.V. Lastarria 29, Depto. 101 Santiago, Chile

    Laboratorio de Endocrinología, Facultad Ciencias Biológicas Facultad de Matemáticas, P. Universidad Católica de Chile Chile
    Search for articles by this author
  • M.E. Casado
    Affiliations
    Instituto Chileno de Medicina Reproductiva Consultorio de Planificación Familiar J.V. Lastarria 29, Depto. 101 Santiago, Chile

    Laboratorio de Endocrinología, Facultad Ciencias Biológicas Facultad de Matemáticas, P. Universidad Católica de Chile Chile
    Search for articles by this author
  • P. Miranda
    Affiliations
    Instituto Chileno de Medicina Reproductiva Consultorio de Planificación Familiar J.V. Lastarria 29, Depto. 101 Santiago, Chile

    Laboratorio de Endocrinología, Facultad Ciencias Biológicas Facultad de Matemáticas, P. Universidad Católica de Chile Chile
    Search for articles by this author
  • V. Schiappacasse
    Affiliations
    Instituto Chileno de Medicina Reproductiva Consultorio de Planificación Familiar J.V. Lastarria 29, Depto. 101 Santiago, Chile

    Laboratorio de Endocrinología, Facultad Ciencias Biológicas Facultad de Matemáticas, P. Universidad Católica de Chile Chile
    Search for articles by this author
  • H.B. Croxatto
    Affiliations
    Instituto Chileno de Medicina Reproductiva Consultorio de Planificación Familiar J.V. Lastarria 29, Depto. 101 Santiago, Chile

    Laboratorio de Endocrinología, Facultad Ciencias Biológicas Facultad de Matemáticas, P. Universidad Católica de Chile Chile
    Search for articles by this author
      This paper is only available as a PDF. To read, Please Download here.

      Abstract

      The contraceptive efficacy of breastfeeding was assessed in 236 healthy urban women who were followed at monthly intervals during the first postpartum year. Proportional hazard models were used to evaluate the influence of time postpartum, menstrual status and breastfeeding pattern upon the risk of pregnancy.
      Time and menstrual status had a highly significant effect on this risk. Those women who remained in amenorrhea had cumulative probabilities of pregnancy of 0.9% and 17% at 6 and 12 months postpartum, respectively. In those who recovered menstrual cycles, the risk rose to 36% and 55% at 6 and 12 months, respectively. Milk supplementation also increased significantly the risk when considered alone but not when time and/or menstrual status were included in the analysis. However, amenorrheic women who introduced bottle feeding, had a higher risk of pregnancy after 6 months postpartum than those who remained fully nursing. The analysis was unable to detect a significant influence of the nursing frequency.
      The results confirm that lactational amenorrhea is an effective contraceptive during the first six months postpartum. The first postpartum bleeding marks a great increase in the risk of pregnancy. Supplementation also increases the risk, particularly in amenorrheic women.
      To read this article in full you will need to make a payment

      Purchase one-time access:

      Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
      One-time access price info
      • For academic or personal research use, select 'Academic and Personal'
      • For corporate R&D use, select 'Corporate R&D Professionals'

      Subscribe:

      Subscribe to Contraception
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect

      References

        • Thapa S
        • Short RV
        • Potts M
        Breastfeeding, birth spacing and their effects on child survival.
        Nature. 1988; 335: 679-682
      1. The Lancet. 1988; : 1204-1205
        • Kennedy KI
        • Rivera R
        • McNeilly AS
        Consensus statement on the use of breastfeeding as a family planning method.
        Contraception. 1989; 39: 477-491
        • Díaz S
        • Rodríguez G
        • Peralta O
        • et al.
        Lactational amenorrhea and the recovery of ovulation and fertility in fully nursing Chilean women.
        Contraception. 1988; 38: 53-67
        • Nelson WE
        8th ed. Textbook of Pediatrics. Saunders, Philadelphia, PA1964: 42
        • Kaplan EL
        • Meier P
        Non-parametric estimation from incomplete observations.
        J Amer Statist Associat. 1959; 53: 457-481
        • Rodríguez G
        • Díaz S
        Breastfeeding and the length of post-partum amenorrhea: a hazards model approach.
        in: Seminar on Biomedical and Demographic Determinants of Human Reproduction, Baltimore, Maryland4–8 January, 1988
        • Cox DR
        Regression models and life tables (with discussion).
        J Royal Statist Soc, Series B. 1972; 34: 187-202
        • Holford TR
        The analysis of rates and survivorship using log-linear models.
        Biometrics. 1980; 36: 299-306
        • Laird N
        • Oliver D
        Covariance analysis of censored survival data using log-linear analysis techniques.
        J Amer Statist Associat. 1981; 76: 231-240
        • Baker RJ
        • Nelder JA
        General linear interactive modelling (GLIM).
        Numerical Algorithms Group, Oxford, England1978 (Release 3)
        • Howie PW
        • McNeilly AS
        • Houston MJ
        • Cook A
        • Boyle H
        Fertility after child birth: Infant feeding patterns, basal PRL levels and postpartum ovulation.
        Clin Endocrinol. 1982; 17: 315-322
        • Díaz S
        • Rodríguez G
        • Marshall G
        • et al.
        Breastfeeding pattern and the duration of lactational amenorrhea in urban Chilean women.
        Contraception. 1988; 38: 37-51
        • Gray RH
        • Campbell OM
        • Apelo R
        • et al.
        Risk of ovulation during lactation.
        The Lancet. 1990; 335: 25-29
        • Prema K
        • Ravindranath M
        The effect of breastfeeding supplements on the return of fertility.
        Stud Fam Plann. 1982; 13: 293
        • Díaz S
        • Miranda P
        • Brandeis A
        • et al.
        A study on the feasibility of suppressing ovarian activity following the end of postpartum amenorrhoea by increasing the frequency of suckling.
        Clin Endocrinol. 1988; 28: 525-535
        • Díaz S
        • Peralta O
        • Juez G
        • et al.
        Fertility regulation in nursing women: I. The probability of conception in full nursing women living in an urban setting.
        J Biosoc Sci. 1982; 14: 329-341
        • International Planned Parenthood Federation
        Statement on breastfeeding, fertility and postpartum contraception.
        November 1989
        • Croxatto HB
        • Díaz S
        Postpartum contraception.
        in: Diczfalusyg E Bygdeman M Fertility Regulation Today and Tomorrow. Raven Press, New York1987: 181-195