Faculty Bibliography

The optimal gestational age for delivery of twin gestations balances the risk to the mother with the risks to the fetus and newborn. Primary considerations should include chorionicity and the presence or absence of other obstetrical complications such as fetal growth restriction or hypertensive disorders of pregnancy. More than half of twin gestations will deliver preterm, and a significant portion will be due to spontaneous labor or medical indications, such that the timing of delivery for twins is typically less determined by the provider discretion. Future studies are needed to assist in clarifying the optimal timing for delivery of twin pregnancies.

Cavernous sinus cavernous hemangiomas in pregnancy are extremely rare lesions. The precise management of these lesions remains unknown. The authors present a case of a cavernous hemangioma in pregnancy, centered within the cavernous sinus that underwent postpartum involution without surgical intervention. A 34-year-old pregnant patient (gravida 1, para 0) presented to an otolaryngologist with persistent headache and left-sided facial pain and numbness in the V1 distribution. While being treated for sinusitis, her symptoms progressed to include a left-sided oculomotor palsy and abducens palsy. Magnetic resonance imaging without contrast revealed an expansile mass within the left cavernous sinus consistent with a cavernous hemangioma. The patient was evaluated by a neurosurgeon who recommended close follow-up and postpartum imaging without surgical intervention. Although the lesion enlarged during pregnancy, the patient was able to undergo an uncomplicated cesarean section at 37 weeks. All facial and ocular symptoms resolved by 9 months postpartum, and MRI showed a decrease in lesion size and reduced mass effect. The authors conclude that nonsurgical management may be a viable approach in patients who have an onset or exacerbation of symptoms associated with cavernous sinus cavernous hemangiomas during pregnancy because postpartum involution may negate the need for surgical intervention.

The aim of this article is to review current information regarding the management of twin gestations and discuss optimal pregnancy length and considerations regarding route of delivery. Limited data are available on the timing and mode of delivery for twins. For apparently uncomplicated twin pregnancies, current recommendations suggest the optimal length of gestation is 38 weeks for dichorionic diamniotic twins, 34-36 weeks for monochorionic diamniotic twins, and 32-34 weeks for monoamniotic twins. In general, vaginal trial of labor may be considered for cephalic-cephalic twins and in cases of cephalic-noncephalic twins where the provider's skills and experience allow. Cesarean is recommended in twin gestations with monoamnionicity, noncephalic presenting fetus, and those at high risk for combined vaginal-abdominal delivery. The optimal management of twin deliveries is controversial, with timing and mode of delivery dependent on multiple factors, including chorionicity, amnionicity, provider experience, and fetal presentation.

PURPOSE OF REVIEW/OBJECTIVE:A complicated but relevant and timely concept, cesarean delivery on maternal request (CDMR) is defined as a cesarean delivery for a singleton pregnancy on maternal request at term in the absence of medical or obstetrical indications. RECENT FINDINGS/RESULTS:Multiple potential risks and benefits exist with both vaginal and cesarean deliveries. A CDMR performed prior to the onset of labor for a mother planning on only one or two children may be reasonable after informed consent and counseling. However, the most concerning complications from cesareans are the neonatal respiratory morbidity and the impact on a mother's future reproductive health, including the risk of abnormal placentation such as placenta previa or accreta. The literature on CDMR is limited and is derived primarily from observational or extrapolated studies. A well designed prospective study does not currently exist but is needed comparing the optimal groups of planned vaginal delivery and planned CDMR. SUMMARY/CONCLUSIONS:Discussions regarding CDMR should be individualized. Until there are more data on CDMR and guidelines implemented, an explicitly executed informed consent should form the framework of any decision regarding mode of delivery.

Mothers should be counseled that the most concerning risks related to maternal request cesarean delivery are neonatal respiratory morbidity and those that may affect the mother's future reproductive health, including life-threatening conditions, such as placenta accreta. The literature suggests that overall risks of maternal complications with cesarean delivery on maternal request are slightly lower than a trial of vaginal delivery and are primarily driven by the avoidance of unplanned or emergent cesarean deliveries and their associated increased rate of complications. When addressing risks and benefits with patients, there are three areas of importance. First, the risks for neonatal respiratory morbidity and abnormal placentation with future pregnancies should be emphasized. Secondly, there are many areas on which studies are lacking. Finally, numerous factors can alter the risks and benefits--such as culture, maternal obesity, and provider background--and should be acknowledged.

OBJECTIVE:To estimate the effect of chorionicity on the risk of stillbirth in twins. METHODS:A retrospective cohort analysis was performed of all twin deliveries of at least 24 weeks of gestation at a single tertiary care center from December 2000 to May 2007. The risk of fetal death with advancing gestation was calculated for monochorionic-diamniotic twins and for dichorionic-diamniotic twins. Overall in utero survival was compared by using Kaplan-Meier analysis and a hazards ratio with 95% confidence intervals estimated to assess the degree of difference. Pregnancies affected by growth abnormalities, anomalies, or twin-twin transfusion syndrome were subsequently excluded and survival by chorionicity similarly compared within these "apparently normal" gestations. RESULTS:Data from 1,000 consecutive twin pairs (196 monochorionic-diamniotic twins and 804 dichorionic-diamniotic twins) were analyzed. Stillbirths occurred in seven (3.6%) monochorionic-diamniotic and nine (1.1%) dichorionic-diamniotic twin pairs. Monochorionic-diamniotic twins had a higher risk of stillbirth compared with dichorionic-diamniotic twins, both overall (log-rank P=.004) and at each gestational age after 24 weeks, with this risk persisting in the subset of 771 (130 monochorionic-diamniotic twins and 641 dichorionic-diamniotic twins) "apparently normal" twins (log-rank P=.039). CONCLUSION/CONCLUSIONS:Monochorionicity has a negative effect on the in utero survival of twins, even among monochorionic-diamniotic twins without abnormalities. LEVEL OF EVIDENCE/METHODS:II.

Prenatal diagnosis has embraced a recent wave of innovative imaging modalities including three-dimensional (3D) ultrasound and fetal magnetic resonance imaging (MRI). Traditional two-dimensional (2D) ultrasonography remains the standard method by which major structural abnormalities are diagnosed antenatally, but advances in technology are opening new doors. Growth in our knowledge about fetal development, improved patient counseling, and more favorable perinatal outcomes are all potential benefits of incorporating new imaging modalities into clinical practice.

Multiple pregnancies currently account for 3% of all births in the United States but are disproportionately responsible for larger rates of prematurity and significant neonatal morbidity. The mean birth age for most multi-fetal pregnancies occurs during the late preterm period when both spontaneous preterm labor and iatrogenic premature birth because of obstetrical or maternal complications are common. Multiples pose numerous unique challenges, emphasizing the significant impact of plurality on late preterm births.

OBJECTIVE:We sought to determine the accuracy of antenatal diagnosis of twin chorionicity at a single tertiary care center and assess the consequences of incorrect diagnoses. STUDY DESIGN/METHODS:Twins with chorionicity diagnosed by ultrasound < or = 24 weeks' gestation were retrospectively reviewed. Chorionicity was assigned by sonographic findings including placental location(s), the lambda and T-signs, and/or fetal gender(s). Postnatal diagnosis was determined by placental histopathologic examination. Medical records of antenatal-postnatal discordant chorionicities were reviewed for adverse sequelae. RESULTS:Chorionicity was correctly assigned antenatally in 392/410 (95.6%) twins. The sensitivity, specificity, and positive and negative predictive values of monochorionicity assessed < or = 14 weeks were 89.8%, 99.5%, 97.8%, and 97.5%. Corresponding statistical values for the second trimester were 88.0%, 94.7%, 88.0%, and 94.7%. Two cases of inaccurate antenatal diagnoses affected patient counseling or were associated with adverse clinical outcomes. CONCLUSION/CONCLUSIONS:Antenatal assessment of chorionicity is accurate; however, incorrect diagnoses do occur and can affect reliable patient counseling and management.

Multiple gestations present unique challenges to the modern obstetrician. Many twin and high-order multiple pregnancies are delivered between 34 and 37 weeks' gestation either secondary to preterm labor or obstetrical complications necessitating intervention. Recognizing the increasing prevalence of multiple gestations and the impact of late preterm deliveries in modern practice, this review analyzes the impact of multiple pregnancies on perinatal outcomes, reviews the strategies to prevent preterm labor, and summarizes potential indications for late preterm delivery. In this paper, "late preterm" has been used instead of "near-term," as the former was considered more appropriate to reflect this subgroup of preterm infants in a workshop on this topic held in July 2005, organized by the National Institute of Child Health and Human Development.