Twin gestations: I. Antenatal care and complications.

In order to determine the occurrence of antenatal complications in twin pregnancies, we examined the medical records of 939 consecutive twin gestations delivered at Women's Hospital, Los Angeles County/University of Southern California Medical Center between 1980-1985. The rates of occurrence of the eight most common antenatal complications were determined and compared with their incidence in singleton gestations. In addition, complication rates were related to zygosity, levels of antenatal care, and time of antenatal diagnosis. Twin gestations had an 83% incidence of antenatal complications, in contrast to a 32% incidence in singleton gestations. The increased complication rate was due to the disproportionate increase in three complications: preterm labor, pregnancy-induced hypertension, and fetal death. Other complications did not occur more frequently in twin gestations than in singleton gestations. Monozygotic gestations were more frequently complicated by fetal death, and dizygotic gestations by pregnancy-induced hypertension.

Group B streptococcus: the effectiveness of screening and chemoprophylaxis.

Although antepartum screening for Group B Streptococcus is not ideal, it may be the most practical approach until rapid tests are proven to be useful in this clinical setting. The efficacy has been established for intrapartum chemoprophylaxis with a penicillin antibiotic of patients with a positive antepartum culture. There is evidence that supports the concept for selective intrapartum chemoprophylaxis in some populations. Intrapartum chemoprophylaxis prevents maternal morbidity. Rapid tests for intrapartum diagnosis of Group B streptococcus colonization appear promising, providing results are available in time for therapy to be administered before delivery.

Heart disease in pregnancy: an update.

New approaches to the diagnosis and functional evaluation of cardiac disease have brought some changes in the means by which the obstetrician should manage cardiac disease in pregnancy. The normal cardiovascular changes in pregnancy and their implications to some specific disorders are discussed.

Multiple hyperbaric exposures during pregnancy in sheep.

Eleven sheep were subjected to hyperbaric comparable to 165 feet of sea water 31 times between the one hundred twelfth and one hundred thirty-seventh days of pregnancy. During 13 dives the maternal and fetal circulations were monitored for bubble formation during decompression. Bubbles were detected by external doppler probes in eight of 12 ewes, but in none of the fetuses. Nine ewes were delivered of normal lambs at term. In one, twin fetuses died during an abnormal labor. The pregnancy of another was terminated by cesarean section after decompression to look for bubbles in the fetal circulation.

Obstetric anesthesia: a national survey.

To assess obstetric anesthesia in the United States, and to determine why more anesthesia personnel are not involved in this subspecialty, a questionnaire was sent to the heads of obstetric and anesthesia services in 1,200 hospitals. Both obstetric and anesthesia respondents agreed on several characteristics of obstetric anesthesia that inhibit more participation by anesthesia personnel. Among others, they identified that: the unpredictability of labor and delivery makes scheduling difficult; obstetricians tend to dictate type and timing of anesthesia; the risk of malpractice claims is increased for obstetric anesthesia; and, finally, larger obstetric services would make it more practical to provide anesthesia services. Regarding availability of personnel and procedures, obstetric units with less than 500 deliveries per year were considerably more under-staffed than the larger units in most areas studied. When general anesthesia was used for cesarean section in these units, it was provided by, or given under the direction of, an anesthesiologist only 44% of the time, whereas in the hospitals with more than 1,500 deliveries per year, an anesthesiologist was present 86% of the time. Likewise, in the small units, personnel classified as "others" were responsible for newborn resuscitation in 24% and 43% of instances after cesarean section and vaginal delivery, respectively. In the hospitals with more than 1,500 deliveries, comparable figures were 4% and 2%, respectively.

Umbilical cord acid base changes associated with perinatal cardiac failure.

Two infants delivered by emergency cesarean section because of fetal distress are described, and the umbilical blood acid-base findings are discussed. One fetus was stillborn, the other died in the immediate neonatal period, and both showed signs of cardiac dilation and failure on postmortem examination. Umbilical cord blood gas determination at the time of delivery showed almost normal values of pH, PcO2, and PO2 in the umbilical vein but acidotic pH with high PCO2 and low PO2 values in the umbilical artery samples. These findings are probably the result of a prolonged umbilical blood circulation time because of fetal cardiac failure. This sluggish perfusion allows the equilibration of fetal blood with maternal intervillous blood, and the findings in the fetal umbilical vein approximate maternal uterine venous values. Umbilical cord acid-base determinations in perinatal surveillance are commonly recommended without specific details. Umbilical artery samples must be obtained to properly assess the metabolic status of the fetus at the time of birth.