X-ray examinations during pregnancy: National Natality Surveys, 1963 and 1980

MR Pelvimetry — A Practical Alternative

Pelvimetry remains a useful technique as part of the assessment of the term breech pregnancy where vaginal delivery is planned. MR pelvimetry is accurate, well tolerated and shows soft-tissue structures as well as bone. It avoids the potentially carcinogenic effects of ionising radiation and is thought to be completely safe for mother and fetus. A technique of MR pelvimetry is described which uses gradient-echo sequences. This quick, practical method makes minimal inroads into valuable scanning time, and may therefore be considered a potentially cost-effective alternative to conventional pelvimetry.

Diagnostic X-ray and ultrasound exposure and risk of childhood cancer

In a population-based case-control study of 642 childhood cancer cases and the same number of matched controls in Shanghai, China, we evaluated the relationship between diagnostic X-ray (preconception, pre- and post-natal) and antenatal ultrasound exposure and the subsequent risk of developing three major types of childhood cancer (acute leukaemia, lymphoma and brain tumours) and all childhood neoplasms combined. Consistent with previous studies, prenatal X-ray exposure was found to be associated with an 80% increased risk of childhood cancers, although the estimation was based on 4% and 2% exposed cases and controls and was only marginally statistically significant (P = 0.08). Post-natal X-ray exposure was also linked with a small elevation in the risk of all cancers and the major categories of malignancies in children. Little evidence, however, was found to relate parental preconception X-ray exposure with the subsequent cancer risk in offspring, regardless of the exposure window and the anatomical site of X-ray exposures. This study adds further to the growing literature indicating that antenatal ultrasound exposure is probably not associated with an increased risk of childhood cancer.

Midwifery care and out-of-hospital birth settings: how do they reduce unnecessary cesarean section births?

In studies using matched or adjusted cohorts, U.S. women beginning labor with midwives and/or in out-of-hospital settings have attained cesarean section rates that are considerably lower than similar women using prevailing forms of care--physicians in hospitals. This cesarean reduction involved no compromise in mortality and morbidity outcome measures. Moreover, groups of women at elevated risk for adverse perinatal outcomes have attained excellent outcomes and cesarean rates well below the general population rate with these care arrangements. How do midwives and out-of-hospital birth settings so effectively help women to avoid unnecessary cesareans? This paper explores this question by presenting data from interviews with midwives who work in home settings. The midwives' understanding of and approaches to major medical indications for cesarean birth contrast strikingly with prevailing medical knowledge and practice. From the midwives' perspective, many women receive cesareans due to pseudo-problems, to problems that might easily be prevented, or to problems that might be addressed through less drastic measures. Policy reports addressing the problem of unnecessary cesarean births in the U.S. have failed to highlight the substantial reduction in such births that may be expected to accompany greatly expanded use of midwives and out-of-hospital birth settings. The present study--together with cohort studies documenting such a reduction, studies showing other benefits of such forms of care, and the increasing reluctance of physicians to provide obstetrical services--suggests that childbearing families would realize many benefits from greatly expanded use of midwives and out-of-hospital birth settings.

Use of diagnostic imaging procedures and fetal monitoring devices in the care of pregnant women

Medical devices and diagnostic imaging procedures such as ultrasound, X-rays, and electronic fetal monitoring devices are used in the medical care of many pregnant women today. The responsibility for the safety and effectiveness of these diagnostic technologies is shared by a number of Public Health Service agencies, one of which is the Center for Devices and Radiological Health (CDRH), a unit within the Food and Drug Administration. The CDRH collaborated with the National Center for Health Statistics (NCHS) in conducting a study of recent trends in the uses of diagnostic ultrasound, medical X-rays, and electronic fetal monitoring devices in the medical care of pregnant women. This study used data from the 1980 National Natality and Fetal Mortality Surveys and the 1987 pretest to the National Maternal and Infant Health Survey. Hospitals and prenatal care providers of the pregnant women contributed information regarding the use of these medical devices. Between 1980 and 1987, ultrasound use more than doubled, increasing from 33.5 percent of pregnancies in 1980 to 78.8 percent in 1987 (P less than 0.001). More ultrasound examinations were performed earlier in gestation in 1987 than in 1980, with 10.1 percent being performed during the first trimester in 1987, compared with 6.9 percent in 1980 (P less than 0.001). Use of external electronic fetal monitoring devices during delivery also increased significantly between 1980 and 1987, from 33.5 percent to 74.6 percent (P less than 0.001). Use of medical X-rays among women with live births remained relatively unchanged, 15.0 percent in 1980 and 15.3 percent in 1987 (P = .282). The implications of these trends are discussed.