A study conducted by a group of researchers at the University of California at Los Angeles and the University of California at Irvine revealed an infant's birth weight may directly be affected by the amount of social support the mother receives during her pregnancy.

"It is critical that psychosocial risk factors that contribute to low birth weight and fetal restriction are identified — especially given the implications for infant morbidity and mortality, healthcare costs and parenting stress," said lead author of the study Pamela Feldman, Ph.D., of the Department of Epidemiology and Public Health at University College London.

The researchers interviewed nearly 250 pregnant women, asking them if the baby's father would support them financially and otherwise with the child, if their parents would support them, and if they had friends around for support and assistance.

Feldman and colleagues found that those women with several sources of support during pregnancy had higher birth weight infants. And, the relationship between social support and birth weight remained even after the researchers took into account other factors often associated with low birth weight — premature delivery, history of stillbirth or spontaneous abortion, and such medical conditions as hypertension or epilepsy.

"That social support is an important predictor of birth weight is emphasized by the finding that it predicts birth weight independently but to the same extent as these well-known medical determinants of birth weight," said Feldman.

While previous studies support the idea that stress contributes to premature birth through its effect on the nervous system, further research is needed to determine if social support affects fetal growth and subsequent birth weight similarly, she said.

Researchers found that social support also may inspire healthier behaviors and lifestyles for pregnant women, discouraging such behaviors as smoking, substance use and poor nutritional intake. And, further results indicated that pregnant women with a higher degree of social support may be more likely to receive treatment for diseases associated with low infant birth weight, such as high blood pressure, heart disease and sickle cell disease.

The researchers concluded that further studies need to be performed to determine the best ways to support those women with less access to social support during pregnancy, and who are at higher risk for having a lower birth weight infant.