Philippine Fertility Transition: Application of the Bongaarts’ Model

by Christian Pattawi Cruz, Master of Arts in Demography (2008)

This study ascertained levels and patterns of fertility and its proximate determinants at the national level, and across type of residence, highest educational attainment and regions applying the Bongaarts’ model, to help explain the fertility pattern in the country for the period 1991-2001. Specifically, it endeavored to identify the specific socio-economic and geographic profile of the fertility decline over the ten-year period that impedes the expected fertility decline over the years. It also examined and evaluated the main proximate determinants of fertility, namely marriage, contraception, and postpartum infecundability and their contribution to the fertility change over a ten-year period, 1993 to 2003 across socio-economic characteristics and geographic locations.

This analysis utilized the 1993 National Demographic Survey (NDS), the 1998 and 2003 National Demographic and Health Survey (NDHS) data. The model developed by Bongaarts (1982) as a framework for an integrated analysis of fertility and the proximate determinants, and the decomposition of fertility change method by Casterline, Domingo and Zablan (1988) was employed for this paper.

Dissecting the contribution of the aforementioned proximate factors to fertility change in the country suggests the significance of contraception and marriage patterns at the national in the 1991-1996 period, and breastfeeding in the 1996-2001 period. The study also noted that fertility change in the country during the first triennium is largely accounted for by the decline in urban fertility brought about by the inhibiting effects of marriage and contraception and the slight decrease in rural fertility resulting from the fertility-inhibiting roles of contraception and postpartum amenorrhea. The national fertility decline during the later triennium on the other hand can be solely attributed to the rural fertility reduction caused by the fertility-inhibiting effect of contraception and breastfeeding, while the urban fertility remained stagnant for the same period.

Meanwhile, significant differentials across the education groups of women manifested that national fertility decline from 1991 to 1996 was mainly due to the decline in fertility among women with elementary and high school education although this was partly offset by the increase in the TFR of women with no education. The highly educated women registered a generally stable fertility performance over the decade under study. In the later period, 1996-2002, the national fertility reduction was mainly contributed by women with at least high school education. Contraception played a crucial part in inhibiting fertility regardless of educational attainment. Breastfeeding also displayed its fertility-inhibiting role only towards the later triennium in almost all of the education groups.

Generally, the combined effect of at least two or all three factors (marriage, contraception, postpartum infecundability) has explained the different fertility trajectories across the regions. In exceptional cases, only one factor yielded to a fertility decline as in the cases of Calabarzon, Western Visayas, and Davao (contraception, 1st triennium).

On the whole, women from urban areas, with elementary education or less, coming from the following regions: NCR, Ilocos, MIMAROPA, Western Visayas, Central Visayas, Zamboanga, and SOCSARGEN are the major groups that display fertility patterns that stalled the fertility decline of the country.

Methodologically, the findings of the study tend to suggest that breastfeeding is the better measure to represent postpartum infecundability. The use of the survey data in calculation of SMAM tended to have a downward bias which can be attributed to the standard errors in the estimates and the truncating of the input data to age group 45-49.