human fertility and it's determinant

Human Fertility and its Determinants

Sopyan, S.Sos, MA.

National Population and Family Planning Board (BKKBN)

South Kalimantan

December 28, 2011

F ertility and Fecundity

• Fertility refers to the number of live births a woman has actually

had.

• Fecundity refers to physiologic al capacity to produce a live birt

h.

Some important concepts

• Marital fertility : the number of live births to married women

• Natural fertility : populations in whi ch no deliberate attempt is made to li mit the number of births

• Reproductive period : A woman’s reproductive period is from menarche to menopause (usually from age 15-49)

Approaches to fertility level study

• Period fertility : looks at fertility cross- sectionally, that is at births occurring duri

ng a specified period of time, normally oneyear.– 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 longit udinally, that is at all births occurring to a s

pecific group of women (e.g. all those born or married in particular period of time)

Some Problems in Measuring Fertility

• It is difficult to establish accurate stati stical records on live births, a child die

s before the birth is registered.• Fertility measurement is complicated

by the fact that fertility involves two parents.

• Not every woman is truly exposed to t he risk of childbearing.

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).

Basic fertility measurements

• Child/Women Ratio• Crude B irth R ate (CBR)• General Fertility Rate (GFR)• Age Specific Fertility Rate

(ASFR)• Total Fertility Rate (TFR)

Basic fertility measurement

•Child/Women Ratio

Children aged 0-4

-Womenaged1 5 4 4

Require few information, no data on births are needed

Sensitive to reporting error and infant mortality


•Crude birth rate (CBR)

•Why is it “crude” ? ...…..

Number of births in year

Population at mid yearX 1,000


•Age specific fertility rate (ASFR)

Births in year to women aged x

Women aged x at mid-year

X 1,000


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 lifetime if she were to pass through her childbearing years conforming to th

e age specific fertility rate of a given year.

– Calculate by adding up ASFRs X 5

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.

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.

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 = ?

Components of fertility

• Biological component– Fecundity : physiological

capacity to produce a live birth

• Social component– different fertility desire in

different society

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

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 throug

h the intermediate variables.• Each intermediate variable may have a nega

tive or positive effect on fertility.

To have a live birth, a woman passes t hrough three stages

• she has sexual intercourse (coitus)

• she become pregnant (conception)

• she successfully completes the period of pregnancy or gestatio

n and gives birth to the child(gestation)

Davis and Blake’s Intermediate Variables

• Intercourse variables– age of entry in sexual unions– permanent celibacy– amount of reproductive period spent aft

er or between unions– voluntary abstinence– involuntary abstinence (impotence, separation

etc)

– coital frequency


• Conception variables– fecundity or infecundity (involunt

ary causes e.g. post-partum amenorrhea)

– use or non use of contraception– fecundity or infecundity (voluntar

y causes e.g. sterilization)


• Gestation variables– Foetal mortality from involuntary

causes– Foetal mortality from voluntary c

auses

Bongaarts’ Proximate DeterminantsModel 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

Family planning methods

• Modern methods– Female/male sterilisation– Pills – IUD– Injectables– Condom– Norplant

• Traditional methods– Rhythm– Withdrawal– Prolonged breast feeding

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.

human fertility and it's determinant

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