A Latent Markov Model with Covariates to Study Unobserved Heterogeneity among Fertility Patterns of Couples Employing Natural Family Planning Methods.PURPOSE
 We adopt the latent Markov model with covariates tailored for data collected at times when a latent process detects the dependence across fertile periods of each woman's cycle. 
Latent Markov Model
We use the historical data from the European Study of Daily Fecundability and we develop an algorithm to determine the fertile window in a woman's cycle according to the rules of the C.A.Me.N. 
the European Study of Daily Fecundability
We use the historical data from the European Study of Daily Fecundability and we develop an algorithm to determine the fertile window in a woman's cycle according to the rules of the C.A.Me.N. 
C.A.Me.N.
symptothermal method proposed by the Centro Ambrosiano Metodi Naturali. 
Centro Ambrosiano Metodi Naturali