Estimation of Fecundability: Levels and Trends in Bangladesh

Abstract

The concept of fecundability - the monthly probability of conception in women - is one of the principal determinants of fertility and one of the most important parameters for studying fertility patterns in different societies. Fecundability affects fertility through its relationship with the average time required for a conception to occur, and can also be thought of as the transition probability for the passage from the susceptible state to pregnancy.

In practice, fecundability is measured in women who are ovulating regularly, that is, pregnant, sterile or post-partum, anovulatory women are excluded. The term natural fecundability is used non-contracepting populations; 'total (or physiological)' fecundability considers all conceptions regardless of outcome, including non-implanted fertilized ova and conceptions aborted spontaneously before the end of the cycle, while 'recognizable' fecundability relates to conceptions recognizable at the end of the conception cycle by the nonoccurrence
of menstruation , and 'effective' fecundability includes only pregnancies ending in live births. In this study, the term 'fecundability' mainly refers to effective fecundability.