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A group of doctors from the University of Connecticut Health Center has created tables and graphs of fetal growth measurements in triplet pregnancies. The data are based on 443 ultrasound scans of 33 triplet pregnancies between 16 and 35 weeks' gestation. Each woman had between 3 and 6 scans during this time period.

Infection with parvovirus during pregnancy can contribute to hydrops in the fetus, a potentially fatal massive accumulation of fluid. In a survey of members of the Society of Perinatal obstetricians, 541 respondents confirmed parvovirus-induced hydrops. In 34% of the cases, there was spontaneous resolution; in 30% of the cases there was death without uterine tranfusion. After uterine transfusion, 29% cases resolved, while 6% died. Almost all of the cases appeared between 16 and 32 weeks.

Survival rates of monoamniotic twins may be significantly improved with early diagnosis, intense monitoring of the fetal heart rate, and judiciously timed cesarean delivery. Monoamniotic twins, sharing a single amniotic sac, are a rare occurrence. Thirteen monoamniotic twins diagnosed in early pregnancy were meticulously supervised. Eight sets of twins were delivered in response to an abnormal fetal heart rate. The survival rate of the closely monitored infants was 92%, compared to a 66% survival rate seen in historical accounts of 77 monoamniotic twins undiagnosed before birth.

Male and female second-trimester fetuses may show slightly different growth patterns as measured by ultrasound, but these differences may not be significant. Researchers measured the head diameter and length of thigh bone and upper arm bone of 288 male fetuses and 251 female fetuses. Gender was found to influence the measurements, but the difference between the two sexes was too small to affect changes in the predicted gestational age of the fetus. Different growth curves for male and female fetuses may not be warranted as accurate estimates of gestational age may be obtained when more than one ultrasonic measurement is used.

The use of several electronic calipers for on-screen ultrasonic measurement of the axis of the fetal heart may enable doctors to detect fetal heart defects. Abnormal heart axis has been associated with congenital heart defects. Researchers performed ultrasound examinations of two hundred low-risk fetuses using several electronic calipers to measure the placement of the heart axis. This measurement was compared to that obtained by a manual method using a protractor. Both methods yielded similar results. All 200 infants were found to have heart axes in a normal position of 43 degrees, which was confirmed by examining infants after birth. The use of electronic calipers may be more convenient for ultrasonic measurement of fetal heart axis. Three to five sets of calipers should be used.

A leading cause of maternal and fetal complications and death is acute intraamniotic infection (sudden infection within the amniotic sac, which surrounds the fetus), and patients who undergo preterm premature rupture of the membranes (PROM) are carefully monitored for infection. Of special concern during monitoring is the fetal biophysical profile, a physiological rating scale on which a fetus can receive a score between 0 and 12. It is possible that PROM results from changes in several related physiological systems, including the fetal umbilical artery (through which blood travels from the fetus to the placenta), and the placenta itself. These abnormalities could include increased vascular resistance in the placenta as a consequence of inflammation. Forty-four patients with PROM underwent testing to establish daily biophysical profiles and umbilical artery velocimetry (measurement of arterial blood flow). After delivery, the placentas were examined. Based on histopathologic analysis, 17 placentas were classified as having no infection (group 1), while 22 were infected (group 2). The remaining five had placental inflammation on the maternal side only (no fetal involvement). Delivery was indicated because of: abnormal biophysical assessment (24 and 77 percent, groups 1 and 2 respectively); labor (65 and 23 percent, groups 1 and 2); and fetal distress (12 percent, group 1 only). Group 2 thus had a higher rate of delivery for abnormal biophysical assessment. These scores were not different for the two groups until 24 hours before delivery, when group 2 scores fell below those of group 1. The results show that placental infection and biophysical profile scores are related. Umbilical artery velocimetry may be a useful noninvasive diagnostic test to predict who will be at risk for infection among patients with PROM. (Consumer Summary produced by Reliance Medical Information, Inc.)

Although most women who become infected with human B19 parvovirus suffer no serious effects, intrauterine infection in some cases has led to fetal edema (fluid accumulation) and death. During an outbreak of the infection in Connecticut, the extent of fetal risk was assessed by evaluating the outcomes of 39 pregnant women who became infected. Thirty-seven had healthy newborns, most of which were delivered at term, near 40 weeks, while the other woman had twins at 35 weeks. No infant was edematous, but one had mild hypospadias, an abnormal opening of the urethra on the underside of the penis. Two patients suffered miscarriages, resulting in an overall pregnancy loss of five percent, a figure lower than most previous estimates. One miscarriage occurred in a patient with a previous history of infertility and low hormone levels during the pregnancy. The other miscarriage, which occurred at 12 weeks, was associated with diseased fetal red blood cells, a condition typical of parvovirus infection. A protocol is proposed for management of pregnant women possibly exposed to parvovirus. If their antibody levels indicate recent viral exposure, repeated ultrasound examinations should be used to monitor fetal health and possible edema. Transfusions may be benefit affected fetuses, but their usage has not been well defined. (Consumer Summary produced by Reliance Medical Information, Inc.)

Accurate growth measurements of twins during pregnancy are difficult to obtain. The growth patterns of individual twins within the same pregnancy can be uneven, resulting in growth retardation of one or both fetuses. It is thought that uneven growth is caused by crowding, genetic variations or a decrease in nutrient supply from the placenta. Uneven growth in twins is associated with a high complication rate. To test the accuracy of standard fetal measurements and to set up a normal reference range, all biometric patterns, such as head circumference, diameter of the parietal bones of the skull (biparietal diameter), the circumference of the abdomen, the ratios of abdomen to head and head to femur (leg bone), and the length of the femur, were used to assess the growth of similarly sized normally growing twin pairs. Serial ultrasonographic examinations were performed on 60 pairs of twins. All twin pairs had less than 20 percent difference in weight at birth. Biparietal diameter was obtained in 79 percent of the fetuses, femur length in 96 percent and abdominal circumference in 99 percent. As the pregnancy progressed the abdominal circumference and head circumference increased in a linear fashion. The average ratio of femur length to abdominal circumference was 22.4, but depended on the age of the fetus. These measurement parameters can be used as standards to monitor the growth of twins growing unevenly. (Consumer Summary produced by Reliance Medical Information, Inc.)