1. Human Fertility and its
Determinants
Sopyan, S.Sos, MA.
National Population and Family Planning
Board (BKKBN)
South Kalimantan
December 28, 2011

2. Fertility and Fecundity
• Fertility refers to the number of
live births a woman has actually h
ad.
• Fecundity refers to physiological
capacity to produce a live birth.

3. Some important concepts
• Marital fertility : the number of live
births to married women
• Natural fertility : populations in which
no deliberate attempt is made to limit the n
umber of births
• Reproductive period : A woman’s
reproductive period is from menarche to
menopause (usually from age 15-49)

4. Approaches to fertility level
study
• Period fertility : looks at fertility cross-
sectionally, that is at births occurring during a s
pecified period of time, normally one year.
– Ratio of live birth that occur in a population during
one year period to the population that bears the
child
• Cohort fertility : looks at fertility
longitudinally, that is at all births occurring to a
specific group of women (e.g. all those born or
married in particular period of time)

5. Some Problems in Measuring
Fertility
• It is difficult to establish accurate statistical
records on live births, a child dies before
the birth is registered.
• Fertility measurement is complicated by
the fact that fertility involves two parents.
• Not every woman is truly exposed to the
risk of childbearing.

6. Sources of data for Fertility Study
• Vital Statistics: Birth Registration
• Census
• Surveys
• Information on Fertility and it’s
determinants usually collected through
surveys
• The 1960s onwards saw many large
scale international efforts to collect
fertility data, ex. WFS (1974-1986), CPS
(1977 – 1985), DHS (1984 – Present).

7. Basic fertility measurements
• Child/Women Ratio
• Crude Birth Rate (CBR)
• General Fertility Rate (GFR)
• Age Specific Fertility Rate (ASFR)
• Total Fertility Rate (TFR)

8. Basic fertility measurement
• Child/Women Ratio
Children aged 0-4
Women aged 15-44
Require few information, no data on births are needed
Sensitive to reporting error and infant mortality

9. Basic fertility measurement
• Crude birth rate (CBR)
• Why is it “crude” ?
...…..
Number of births in year
Population at mid year
X 1,000

10. Basic fertility measurement
• Age specific fertility rate (ASFR)
Births in year to women aged x
Women aged x at mid-year
X
1,000

11. Basic fertility measurement
Total fertility rate (TFR)
– most widely used by demographer
– TFR : The average number of live-births of a
woman (or group of women) during her lifeti
me if she were to pass through her childbeari
ng years conforming to the age specific fertili
ty rate of a given year.
– Calculate by adding up ASFRs X 5

12. Cohort Measurement
Parity Progression Ratio (PPR)
– The probability of having another
child given that one has already had
a certain number.
– Women in older age group are
usually chosen for calculating PPR.

13. Reproductivity
• Gross Reproduction Rate
– Sum of ASFRs calculated for female births
only
• Net Reproduction Rate
– A female born will only replace her mother
provided she live to the age of her mother
as on the day that she was born.

14. Replacement level fertilty
• The level of fertility at which a couple has
only enough children to replace
themselves, or about two children per
couple.
– TFR = ?
– GRR = ?
– NRR = ?

15. Components of fertility
• Biological component
– Fecundity : physiological
capacity to produce a live birth
• Social component
– different fertility desire in
different society

16. Ovulation
Eggs released
Sexual Intercourse
Sperms released
Human reproduction
Egg fertilized by sperm
Conception
Implementation in uterus
Parturition Abortion
Nine months
or 280 days
Gestation
Period

17. Davis and Blake’s Intermediate Variables
(1956)
In 1956 Davis and Blake proposed a
framework for analyzing the bio-medical
determinants of fertility. They identified 11
intermediate variables divided into three
blocks.
• Direct effect on fertility
• Social factors indirectly effect fertility through the
intermediate variables.
• Each intermediate variable may have a negative
or positive effect on fertility.

18. To have a live birth, a woman passes
through three stages
• she has sexual intercourse
(coitus)
• she become pregnant
(conception)
• she successfully completes the
period of pregnancy or gestation
and gives birth to the child (gesta
tion)

19. Davis and Blake’s Intermediate Variables
• Intercourse variables
– age of entry in sexual unions
– permanent celibacy
– amount of reproductive period spent after or
between unions
– voluntary abstinence
– involuntary abstinence (impotence, separation etc)
– coital frequency

20. Davis and Blake’s Intermediate Variables
• Conception variables
– fecundity or infecundity (involuntary
causes e.g. post-partum amenorrhea)
– use or non use of contraception
– fecundity or infecundity (voluntary
causes e.g. sterilization)

21. Davis and Blake’s Intermediate Variables
• Gestation variables
– Foetal mortality from involuntary
causes
– Foetal mortality from voluntary
causes

22. Bongaarts’ Proximate Determinants Model
of Fertility Analysis
John Bongaarts refined the list of variables to eight
proximate determinants
The model focuses on 4 of the proximate
determinants. The TFR in any society is a function
of the Total Fecundity of a population modified by
the levels of the four intermediate variables.
TFR=Cm . Cc . Ci . Ca . TF
• Proportion of women married or in sexual unions
• use of birth control
• breast feeding and lactational amenorrhoea
• induced abortion

23. Family planning methods
• Modern methods
– Female/male sterilisation
– Pills
– IUD
– Injectables
– Condom
– Norplant
• Traditional methods
– Rhythm
– Withdrawal
– Prolonged breast feeding

24. Class Exercise
Please answer the following questions.
• What is the current level of fertility in your province?
• What is the major proximate determinants operating
to change fertility in your province? Provide reasons.
• What is major socio-economic variable responsible
for changing levels of fertility in your province?
Provide reasons.