The Effect of Activity Restriction on Infant's Birth Weight and Gestational Age at Birth: PRAMS Data Analysis

Activity restriction is extensively prescribed for pregnant women with major comorbidities despite the lack of evidence to support its effectiveness in preventing preterm birth or low birth weight.

To determine the moderation effect of home activity restriction for more than a week on infant's birth weight and gestational age at birth for high-risk women with obstetrical and medical comorbidities.

A secondary analysis of 2004-2008 New York Pregnancy Risk Assessment Monitoring System was conducted with 1426 high-risk women.

High-risk group included 41% of women treated with activity restriction and 59% of those not treated with activity restriction. Women with preterm premature rupture of membrane (PPROM) who were treated with activity restriction had a lower infant birth weight ( b = -202.85, p = ≤.001) and gestational age at birth ( b = -.91, p = ≤.001) than those without activity restriction. However, women with preterm labor and hypertensive disorders of pregnancy who were not treated with activity restriction had lower infant gestational age at birth ( b = -96, p = ≤.01) and ( b = -92, p = ≤.001), respectively, compared to those who were treated with activity restriction.

Findings suggest a contrary effect of activity restriction on infants born to women with PPROM, which is a major reason for prescribing activity restriction. The current study results may trigger the need to conduct randomized control trials to determine the effect of severity of activity restriction on maternal and infant outcomes.