The frequency and spectrum of congenital anomalies in natural family planning users in South America: No increase in a case-control study Article

cited authors

  • Castilla, EE; Lopez-Camelo, JS; Da Graça Dutra, M; Queenan, JT; Simpson, JL

fiu authors


  • Users of natural family planning (NFP) practice periodic abstinence, leading many to reason that such couples should show increased anomalies in offspring as a result of fertilization involving aging gametes. In an effort to complement our NFP cohort study, we currently conducted a case-control study in the same region (South America) in which the largest number of cases have been recruited for our cohort NFP study. During 1992-94, 5324 case-control pairs of mothers were interviewed during the immediate postpartum period in 18 maternity hospitals participating in the Latin-American Collaborative Study of Congenital Malformations: ECLAMC (Spanish acronym for Latin-American Collaborative Study of Congenital Malformations). Natural family planning (NFP) usage was recorded in 6% of mothers in the ECLAMC sample studied (n = 10,648). Overall, no significant differences in frequency of NFP usage were observed between malformed cases (349/5324 = 6.6%) and normal controls (303/5324 = 5.7%) (χ2 = 3.3; df = 1; p > 0.05). No significant differences in sex ratios were observed between children of NFP user and non-user mothers. Of special interest is the lack of association between NFP and Down syndrome, the sentinel phenotype for the hypothesis of delayed fertilization (aging gametes).

publication date

  • December 1, 1997

Digital Object Identifier (DOI)

start page

  • 395

end page

  • 404


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