In the United States, black infants are at higher risk of prematurity and low birth weight than white infants. The increased risk has been partly attributed to less timely prenatal care received by black women than white women. Furthermore, studies that control for timing of first prenatal visit and number of visits continue to ascertain comparable black-white disparity in adverse pregnancy outcomes. However, the type of prenatal service offered, which may affect pregnancy outcome, has not been extensively studied. Thus, the objective of this retrospective study was to determine whether differences in type of prenatal procedures received by black and white women exist. The three technological procedures selected were ultrasonography, which is widely used throughout pregnancy, tocolysis, which is an intervention to prevent preterm delivery, and amniocentesis, which is a routine screening procedure among women 35 years or older to detect chromosomal abnormalities. The selected procedures were representative of the variety of prenatal technologies. Study data were obtained from birth certificates issued for births occurring in the United States in 1990. Study subjects were limited to non-Hispanic black and white women for whom the maternal education and technology sections of the birth certificate were completed. In addition, the amniocentesis analysis was limited to women aged 35 years or older.

The results presented incorporate adjustment for maternal age, education, marital status, residence, live-birth order, timing of first prenatal care visit and plurality of gestation. Ultrasonography was used 12% less frequently among black women than white women, while amniocentesis was used 52% less frequently among black women. Tocolysis use varied by plurality. Black women with singleton births were 6% more likely to use tocolysis, while black women with multiple births were 31% less likely to use the procedure.

Clearly, a significant racial disparity for the use of amniocentesis was found. Although black women were only slightly less likely to use ultrasonography, this racial difference translates into a large number of black women who were underserved since ultrasonography is common procedure used throughout the course of pregnancy. Regardless of plurality, the difference in use of tocolysis may reflect notable underuse among black or overuse among white women. Tocolysis is primarily used to suppress preterm labor, and black women are threefold more likely than white women to experience preterm delivery.

Although this study is one of the first to examine racial disparity concerning type of prenatal services on a nationwide basis, the use of data derived from the 1990 birth certificates has several limitations. First, the data on prenatal care technologies may be unreliable since this section has only been in use since 1989. Second, the data is lacking valuable information on the specifics of the procedures, such as the timing of and the need for the procedure. Differential use does not necessary reflect differential need. Thus, differential use may not be a source of differential pregnancy outcomes between black and white women. Furthermore, although physicians may be more apt to offer technological procedures than midwives and nurses, the type of prenatal care provider can not be determined from birth certificates. Another problem lies in the use of live birth certificates, as this approach does not consider the utilization among pregnant women who later went on to miscarry or have medically induced abortions.

Although the study suggests that differences in use of prenatal care technologies exist, further research is needed. In order for a pregnant woman to use these technologies, multiple sequential decisions are involved. First, a woman must have access to prenatal care, then a prenatal care provider must provide the woman with the option to undergo the procedure, and finally a woman must make a decision whether to accept the use of the procedure. Thus, more comprehensive studies using other sources of data should follow to verify the existence of this finding. If the disparity prevails, then the source or the decision stage that contributes to the disparity needs to be determined in order to help alleviate this racial difference.