Faculty Bibliography

We longitudinally assessed intrauterine ultrasonic growth parameters (biparietal diameter, head circumference, abdominal circumference, and femur length) in 60 pairs of concordant twins. Head circumference to abdominal circumference and femur length to abdominal circumference ratios were calculated. Estimated fetal weight curves were created with the formula of Shepard et al., incorporating biparietal diameter and abdominal circumference, as well as that of Hadlock et al., incorporating femur length and abdominal circumference. Biparietal diameter was obtained in only 79% of fetuses, whereas femur length and abdominal circumference were obtained in 96% and 99% of fetuses, respectively. The intrauterine growth of abdominal circumference appears to be linear between 18 and 40 weeks, fitting the simple equation abdominal circumference = -4.5 + 0.97 gestational age (gestational age in weeks). The mean femur length to abdominal circumference ratio is 22.4 +/- 1.5 and appears to be gestational age independent between 20 and 40 weeks. The head circumference to abdominal circumference ratio decreases as gestational age advances in a linear fashion. Estimated fetal weight curves by the formulas of both Shepard et al. and Hadlock et al. fit second-order polynomial equations. Neither formula appears to be superior in estimating fetal weight in twin gestations, although that of Hadlock et al. can be used more frequently since biparietal diameter cannot always be obtained in both twins.

The effect of magnesium sulfate (MgSO4) in intrapartum fetal behavior as judged by heart rate cyclicity was investigated by comparing the fetal heart characteristics of 15 term fetuses whose mothers received MgSO4 with a control group of 54 healthy term fetuses whose mothers received no antepartum medications. The duration of different fetal heart cycles and percentage of time spent in a particular cycle except for cycle C (6 to 10 beats per minute) were not different between groups. Seventy-seven percent of fetuses of the study group versus 24% of fetuses in the control group exhibited markedly diminished variability (cycle A) and 8% versus 63%, respectively, experienced cycles of increased variability (cycle D). Our observations may explain the conflicting conclusions of previous reports regarding the affect of MgSO4 on fetal heart rate variability

Tuberous sclerosis is an autosomal dominant disorder of hamartoma formation in which manifestations may occur in skin, brain, and viscera. In the past, it was believed that the typical presentation included seizures, mental retardation, and facial angiofibromas ('adenoma sebaceum'). This disorder is now recognized to show wide variability of expression. There are only four cases of tuberous sclerosis in pregnancy in the literature. Two of these had favorable maternal and fetal outcomes and the remaining two presented with serious maternal and fetal complications. These included acute intra-abdominal bleeding due to a ruptured renal tumor, which led to renal failure requiring hemodialysis, and severe preeclampsia with pathologically enlarged kidneys noted at the time of cesarean section. This study presents two more cases of tuberous sclerosis in pregnancy. The first case had renal involvement with bleeding into a renal cyst, renal failure, preeclampsia, and severe intrauterine growth retardation. The second case was complicated by preterm premature rupture of the membranes and preterm labor. Renal involvement appears to be the single most important prognostic factor in pregnancies with tuberous sclerosis. Renal evaluation should be performed in any patient who presents for preconceptional counseling

The cyclic variation in fetal heart rate (FHR) patterns in preterm fetuses throughout labor was studied with a retrospective analysis of 49 FHR tracings. All fetuses were born preterm in good condition, and 92% exhibited the ability to change FHR cycles. A cycle was defined as an FHR pattern with consistent long-term variability in terms of amplitude range. The FHR cycles were significantly shorter in the second stage of labor as compared to the latent and active phases. Cycles of markedly diminished variability (less than or equal to 2.5 beats per minute) were observed in 16% of the fetuses during the latent phase and had a mean duration of 42 minutes, in 21% of the fetuses during the active phase with a mean duration of 68.3 minutes and in 8% of the fetuses during the second stage with a mean duration of 28.5 minutes. Knowledge of the normal length and frequency of FHR cycles is imperative for the correct interpretation of intrapartum FHR patterns in preterm fetuses

Placental pathology is rarely a part of the training for either obstetrician or pathologist. As a result there has been confusion regarding the potential benefits of routine placental examination. These benefits include clarification of the causes of many adverse pregnancy outcomes, improvement of the risk assessment for future pregnancies, and ascertainment of newborn risk for long-term neurodevelopment sequelae. Information on placental abnormalities may reveal the presence of chronic fetal insults and allow their differentiation from acute (peripartum) stresses. Current methods of risk assessment fail to identify the majority of pregnancies that end in prematurity, stillbirth, growth retardation, or fetal distress. We suggest that placental pathology should be a routine component of obstetric-neonatal care

Thrombocytopenia complicating pregnancy occurs with four major nonmalignant conditions found in the reproductive age group: thrombotic thrombocytopenic purpura, hemolytic uremic syndrome, pregnancy-induced hypertension, and immune thrombocytopenic purpura. A case of thrombotic thrombocytopenic purpura occurring in a pregnant patient is presented, along with a review of the literature.

With the increasing survival rates of the extremely premature infants, counseling patients as to the potential outcome of the pregnancy is difficult. Traditional methods of basing survival rates on gestational age and actual birthweights have limitations. This study compares survival rates based on ultrasonically estimated fetal weights to those of actual birthweights and demonstrates an excellent correlation at this institution. It is suggested that individual institutions should construct their own neonatal survival rates based on estimated fetal weights for the extremely premature fetus to counsel better patients at risk for early delivery.

The fetal biophysical profile may assist the clinician to ascertain the fetal condition at the time of testing (acute markers), the degree of fetal compromise (gradual hypoxia concept), the presence of chronic fetal stress or possibility of in utero death due to cord accident (oligohydramnios), intrapartum complications such as abnormal heart rate patterns and abruptio (grade III) placenta, and impending fetal infection in patients with PROM (if performed daily). In addition it may identify major congenital anomalies which may drastically alter obstetric management. It remains to be seen if the use of computer-assisted systems for concurrent observation of the biophysical activities, or the addition of more biophysical variables, will further improve the accuracy of this testing method.

The presence or absence of cyclic variation (cyclicity) of fetal heart rate patterns was prospectively investigated in fetuses between 25 and 32 weeks' gestation. All fetuses were delivered by cesarean section before the onset of labor. The relationship between the presence or absence of fetal heart rate cyclicity and fetal acidosis, as determined by cord pH measurements, was investigated. The sensitivity, specificity, positive predictive value, and negative predictive value of this method in predicting fetal acidosis were: 100, 90, 50, and 100%, respectively. All fetuses with reactive nonstress tests also had fetal heart rate cyclicity present and none were acidotic at birth. The majority of fetuses (68.8%) with nonreactive nonstress tests had fetal heart rate cyclicity present and none were acidotic; fetuses with nonreactive nonstress tests and absence of fetal heart rate cyclicity were acidotic in 50% of the cases. These preliminary data suggest that the presence or absence of fetal heart rate cyclicity may help to select the healthy preterm fetuses with nonreactive nonstress testing who are in good condition and therefore in no need for further testing.