title: Pregnancy outcome in natural family planning users: cohort and case-control studies evaluating safety.
abstract: Conceptions involving aging gametes are of relevance to natural family planning (NFP) because women using NFP to avoid pregnancy abstain from intercourse during the fertile time of the cycle. To help verify the safety of pregnancies occurring among NFP practitioners, our group has, since 1986, conducted a large cohort study involving six experienced NFP centers. Timing of conception was determined from NFP charts, in which women recorded days on which intercourse occurred. The number of days from the most probable conception intercourse to probable day of ovulation was first determined, and used as an estimate of the time gametes remained in the genital tract before fertilization. Several studies have already been completed, cohort as well as case-control in nature.
authors.affiliation: Baylor College of Medicine, Houston, TX, USA.
authors.forename: J L
authors.initials: JL
authors.lastname: Simpson
authors.forename: R H
authors.initials: RH
authors.lastname: Gray
authors.forename: A
authors.initials: A
authors.lastname: Perez
authors.forename: P
authors.initials: P
authors.lastname: Mena
authors.forename: M
authors.initials: M
authors.lastname: Barbato
authors.forename: E E
authors.initials: EE
authors.lastname: Castilla
authors.forename: R T
authors.initials: RT
authors.lastname: Kambic
authors.forename: F
authors.initials: F
authors.lastname: Pardo
authors.forename: G
authors.initials: G
authors.lastname: Tagliabue
authors.forename: W S
authors.initials: WS
authors.lastname: Stephenson
authors.forename: A
authors.initials: A
authors.lastname: Bitto
authors.forename: C
authors.initials: C
authors.lastname: Li
authors.forename: V H
authors.initials: VH
authors.lastname: Jennings
authors.forename: J M
authors.initials: JM
authors.lastname: Spieler
authors.forename: J T
authors.initials: JT
authors.lastname: Queenan
mesh_terms: D000022:Abortion, Spontaneous; D000818:Animals; D016022:Case-Control Studies; D015331:Cohort Studies; D004314:Down Syndrome; D005193:Family Planning Services / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D010061:Ovulation Detection; D011247:Pregnancy; D011256:Pregnancy Outcome