Physical activity during pregnancy and fetal outcomes: a case-control study.
OBJECTIVE
To investigate the relationship between physical activity during the second trimester pregnancy and low birth weight, preterm birth, and intrauterine growth restriction.


METHODS
Case-control study including 273 low birth weight newborns and 546 controls carried out in the city of São Paulo, Southeastern Brazil, in 2005. Low birth weight cases were grouped into two subsamples: preterm birth (n=117) and intrauterine growth restriction (n=134), with their related controls. Information was collected by means of interviews with mothers shortly after birth and transcription of medical records. Data were analyzed using conditional multiple and hierarchical logistic regression.


RESULTS
Light physical activity for over 7 hours per day was shown to be protective against low birth weight (adjusted OR=0.61; 95% CI 0.39-0.94) with a dose-response relationship (p-value for trend=0.026). A similar trend was found for intrauterine growth restriction (adjusted OR=0.51; 95% CI 0.26-0.97). Homemaking activities were associated as a protective factor for both low birth weight and preterm birth (p-value for trend=0.013 and 0.035, respectively). Leisure-time walking was found to be protective against preterm birth.


CONCLUSIONS
Mild physical activity during the second trimester of pregnancy such as walking has an independent protective effect on low birth weight, preterm birth, and intrauterine growth restriction.
Departamento de Pedagogia do Movimento do Corpo Humano, Escola de Educação Física e Esporte, Universidade de São Paulo, São Paulo, SP, Brasil. mytakito@gmail.com
Monica Yuri
MY
Takito
Maria Helena D'Aquino
MH
Benício
D001938:Brazil; D016022:Case-Control Studies; D005260:Female; D005317:Fetal Growth Retardation / Q000517:prevention & control*; D006801:Humans; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D009043:Motor Activity / Q000502:physiology*; D011247:Pregnancy; D011256:Pregnancy Outcome; D011262:Pregnancy Trimester, Second; D047928:Premature Birth / Q000517:prevention & control*; D012959:Socioeconomic Factors