Smoothed breastfeeding durations and waiting time to conception

Area of Science:

• Reproductive health
• Demography
• Maternal and child health

Background:

• Breastfeeding is a key factor in fertility regulation post-childbirth.
• Retrospective survey data on breastfeeding and postpartum amenorrhea often contain inaccuracies like digit preference (heaping).
• These data errors can obscure the true contraceptive effect of breastfeeding.

Purpose of the Study:

• To investigate the contraceptive effect of breastfeeding.
• To assess how data heaping errors affect the observed relationship between breastfeeding and conception.
• To quantify the reduction in conception risk attributable to breastfeeding.

Main Methods:

• Utilized data from a 1987 Indian survey.
• Employed B-spline smoothing to correct for digit preference errors in breastfeeding and postpartum amenorrhea data.
• Applied multivariate risk models to analyze the relationship between breastfeeding and conception.

Main Results:

• Breastfeeding, even after the mother's menstruation resumes, demonstrably reduces the risk of conception.
• Data heaping errors were found to attenuate, or weaken, this observed relationship.
• After adjusting for data errors, breastfeeding was associated with a 63% reduction in the rate of conception, compared to an unadjusted 47% reduction.

Conclusions:

• Breastfeeding provides a significant contraceptive benefit, even beyond the return of menstruation.
• Statistical smoothing of data is crucial for accurately assessing the impact of breastfeeding on fertility.
• Accurate data on breastfeeding duration and patterns are essential for understanding reproductive patterns and family planning.