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Patterns and Determinants of Conception Wait and Fecundability in
Bangladesh
Syeda Shahanara Huq
Md.Moshiur Rahman
Associate Professor,Department of Statistics Jahangirnagar University,Dhaka-1342,Bangladesh
and
Makio Ishiguro
Professor,The Institute of Statistics Mathematics,Tokyo 106-8569,Japan
Time Schedule : Secondary data(which is known as Demographic and Health Survey
1999-2000)for this project has been obtained in May 2003 from Mitra and Associates Ltd.
Dhaka,Bangladesh.Data on conception wait and other associated variables were extracted
during the period of June and July,2003.Conception wait data is time dependent and
some data are censored.All the independent variables included in the analysis are not time
dependent.Many of the articles and references were collected for the literature review.We
have reviewed the recent published works about thetopic through out the project period.
Both the theoretical and applied findings from various published articles were gathered in
the project.From September to December 2003 data have been analyzed using life table
technique,cross-table and Cox proportional hazard regression models.After computing
the median conception wait,we computed the fecundability for Bangladeshi women and
their levels with respect to different factors.By the end of December 2003 we completed
the analysis of the conception wait data to identify the factors affecting the conception
wait.We then concentrated writing the report of the ISM Co-operative project from
January 2004.Final report was completed on March 2004.
Summary Report
of the ISM Co-operative Research Project(No.15-CRP-1025)for the Year 2003-2004
The time it takes for a couple from initiating attempts to become pregnant until concep-
tion occurs(time-to-pregnancy)is gaining importance as a measure of natural fecundity
(Weinberg and Dunson,2000).It is one of the principal determinants of fertility.The
duration of time from the marriage to the first recognized conception is known as concep-
tion wait.Fecundability can be computed from the conception wait and it is a practical
problem of estimating the waiting time to conception in Bangladesh.The objectives of the
work are as(1)to determine the levels and differentials of the waiting time from marriage
to first recognized conception and fecundability,and(2)to identify the determinants of
conception wait in Bangladeshi women.Fecundability affects fertility through its relation-
ship 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
(Perrin and Sheps,1964).
Data used in this study come from a nationally representative Bangladesh Demographic
and Health Survey(DHS)1999-2000(Mitra et al.2001).Data provide complete birth
and contraceptive use history of 10544 ever married women aged 10-49 years which are
very useful for estimating waiting time to conception and fecundability.To estimate
fecundability we have considered the median waiting time to first conception among non-
contracepting women.Since censored observations are involved at waiting time to first
conception so calculation of median waiting time is based on life table technique.Exposure
period is obtained by date of interview minus the length of gestation for those women who
are pregnant at interview date; nine months prior from date of births for those women
who had a live birth.Exposure period can be censored either by interview or dis-solution
of union.
Since the exact date of contraceptive use is not provided in DHS 1999-2000,so to calculate
the non-contracepting interval we used the information on the number of children at first
contraceptive use.We have considered those women who never used any contraceptive
method or those who have at least one child at the time of the first use of contraceptive
method as non-contracepting women.For this analysis we have found 6387 segments of
non-contracepting intervals that constitute
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