Prenatal Maternal Stress and Prematurity: A Prospective

Prenatal Maternal Stress and Prematurity: A Prospective Study

of Socioeconomically Disadvantaged Women

Medical risks only predict one half to two thirds of adverse pregnancy outcomes. Even though elevated levels of epinephrine and norepinephrine reduces bloodflow and oxygen to the fetus, which may inhibit fetal growth and precipitate labor, studies that have explored stress factors related to low birthweight and premature delivery have found mixed. Researchers Lobel, Dunkel-Schetter, and Scrimshaw (1992) pursued the relationship between stress and adverse pregnancy outcomes in greater detail in their study of disadvantaged women. They looked at stress more holistically than previous studies and found stronger relationships.

The first major difference between this and previous studies was that Lobel et al. integrated biomedical data and psychosocial data, as opposed to just one or the other. They also looked at the relationship between weeks of gestation and birthweight, which many researchers overlooked. These researchers' operationalization of the stress construct for their study was more explicit than other researchers', and they sought to eliminate the misidentification of medical complications during pregnancy as an adverse birth outcome. The final issue with previous research they tried to rectify was the misuse of statistical tests and analyses.

The construct the researchers tested, in conjunction with biomedical data about pregnancy risk factors, was stress -- specifically the response to the stimulus of life events, emotional state anxiety, and perceived stress. Even though the test sample was fairly homogenous, they also examined the effect social class, age, ethnicity, race, marital status, parity (whether this was the first child or not) and socioeconomic status on birth outcomes.

The sample consisted of 130 women receiving prenatal care at a public clinic with a sliding pay scale (so pretty much all low-income women). Minors were excluded from the study, so the ages ranged from 18-42, with an average of about eleven years of formal education. There was a mix of Latina, African-American, and Anglo women with about eighty percent of them living with the baby's father and twenty percent receiving monetary support from him. These women were interviewed and surveyed at regular intervals throughout their pregnancies about stress inducing events in their lives, how well they felt they could control important things in their lives, how much anxiety they felt, etc.

Hypothesis:

Using structural equation modeling (SEM), the researchers tested and estimated causal relations between medical risk, stress, and adverse birth outcomes using a combination of statistical data and qualitative causal assumptions -- like the perception of stress. Their hypothesis was that a combination of medical risk factors and stress would correlate with adverse birth outcomes. They found that parity has no relationship to stress or birthweight, medical risk does not correlate with stress, and that women who were under more stress gave birth to lighter babies regardless of time of gestation.