Sociobiological variables and pregnancy outcome.

Recent advances are beginning to shed light on the mechanisms whereby adverse psychosocial factors can influence pregnancy outcome. High levels of maternal stress have been linked to endocrine disturbances, which in turn increases the risk of preterm labor considerably. These observations have been supported by experimental animal models. Birth weight is subject to considerable ethnic variation, and on its own is a nonspecific indicator of pregnancy outcome. The benefits of social and psychological intervention have been best documented in the intrapartum situation, whereas antenatal intervention is most likely to be of benefit when focused on improving socioeconomic conditions and access to healthcare providers.