Breastfeeding and waiting time to conception for Malay women: a tale of two surveys
VanLandingham, M.
Social Biology 40(3-4): 215-223
1993
ISSN/ISBN: 0037-766X PMID: 8178190 DOI: 10.1080/19485565.1993.9988848Document Number: 332656
In 1987, Goldman et al. analyzed data from the Malaysian World Fertility Survey (MWFS) and found that noncontracepting Malaysian women had a birth interval 8 months longer than expected from their relatively short duration of breast feeding (5.9 months). Analysis by ethnic group showed that it was the Malays who had the longer birth interval, with the Chinese women close to predicted times. In the present study, an attempt was made to reproduce Goldman's findings and then to compute comparable measures from data from the Malaysian Family Life Survey (MFLS) in order to explain this phenomenon. The MWFS, conducted during August-December 1974, asked if a baby was breast fed and, if so, for how many months. Waiting time to conception was calculated, with median waiting times and medium breast feeding times calculated using increment/decrement tables. Current decrement calculations produced estimates very close to Goldman's. In the MFLS, conducted between August 1976 and August 1977, women were asked if they breast fed, even if it was for a few days. Median birth intervals and breast-feeding durations were calculated using lifetables for births between January 1972 and December 1974. Results showed that median birth intervals were very similar for the 2 surveys, but median duration of breast feeding was about double in the MFLS for all breast-fed babies born in 1972-74, with the discrepancy in the 2 surveys holding true for the Malays and not the Chinese. Thus, a problem in the interpretation of the breast-feeding question by MWFS respondents seems to account for the difference in breast-feeding durations given in the 2 surveys and also for the difference between the MWFS and other World Fertility Surveys (WFS). Malay women seem to have limited their reporting of months of breast feeding to months of full breast feeding. The Chinese women may have had less problem in this regard since the Chinese duration of any breast feeding was very short. Also, weaning may be a more distinct event for the Chinese women, whereas the Malays may extend weaning over a longer period of time. Responses may also have been influenced by the relative unpopularity of breast feeding in Malaysia during the early 1970s as compared to other WFS countries. Substituting MFLS data for breast feeding duration data reported in the MWFS increased Malaysia's waiting time to 18 months, only 3 months less than the observed WFS value of 21 months. This illustrates the importance of phrasing in questionnaires. Even the more detailed questions in the MFLS, however, do not provide data which sufficiently explain how Malaysia differed from other WFS countries during the 1970s. Further research on the balance of breast feeding and supplemental feeding and on perceived social approval is required to answer this question.