Birth Spacing and Parents' Physical and Mental Health: An Analysis Using Individual and Sibling Fixed Effects

Area of Science:

• Reproductive Health
• Public Health
• Family Studies

Background:

• Extensive research links birth spacing to parental health, primarily using observational designs.
• Previous studies often adjusted only for observable confounders, potentially limiting causal inference.
• The impact of birth spacing on non-pregnancy-related parental health remains incompletely understood.

Purpose of the Study:

• To investigate the association between birth spacing and parental health outcomes using robust statistical methods.
• To examine short-, medium-, and long-term general practitioner consultations for mothers and fathers.
• To differentiate the effects of birth spacing from stable individual and family background characteristics.

Main Methods:

• Utilized Norwegian register data for a large-scale study.
• Employed individual fixed-effects models for short-term outcomes to control for time-invariant parental characteristics.
• Applied sibling fixed-effects models for medium- and long-term outcomes to account for shared family background.

Main Results:

• Observational analyses mirrored prior literature, associating extreme birth intervals with poorer health.
• Individual fixed-effects models indicated a modest negative short-term impact of short birth intervals on maternal mental health.
• Evidence for modest effects of birth spacing on physical health across all timeframes was ambiguous.

Conclusions:

• Birth spacing behavior appears to have small to negligible effects on non-pregnancy-related parental health.
• Advanced fixed-effects modeling suggests confounding may explain some previously observed associations.
• The findings highlight the importance of rigorous methodology in understanding the complex relationship between family planning and parental health.