Evidence-Based Labor Management
- Twins represent 3.2% of all live births; however, they account for 20.0% of all preterm deliveries, with 60.0% and 10.7% of twins delivered before 37 and 32 weeks’ gestation, respectively. Twin pregnancies have 5 times higher risk of early neonatal and infant death related to prematurity. Monochorionic twins have a higher incidence of both indicated and spontaneous preterm delivery than dichorionic twins. Transvaginal ultrasound of the cervical length before 24 weeks’ gestation is the best tool to predict preterm birth, independent of other risk factors.
- Twins represent 3.2% of all live births. However, they account for 20% of all preterm deliveries, with 60% delivered before 37 weeks and 10.7% before 32 weeks of gestation. Twin pregnancies have a 5 times higher risk of early neonatal and infant death related to prematurity. Monochorionic twins have a higher incidence of both indicated and spontaneous preterm delivery than dichorionic twins. Additional risk factors include a history of preterm delivery and cervical surgery. The transvaginal cervical length before 24 weeks is the best factor to predict preterm birth, independent of other risk factors.
- Monoamniotic twin pregnancies are rare, but early diagnosis of such pregnancies is critical, as the incidence of complications in these pregnancies is much higher than in diamniotic or dichorionic twin pregnancies. Overall, only 70% of all monoamniotic twins will survive. Furthermore, approximately half of fetal deaths in these pregnancies are because of the high incidence of fetal anomalies (15%–25%), such as twin reversed arterial perfusion sequence and conjoined twinning. Therefore, early anatomy screening in the first trimester of pregnancy is recommended.
- Twin pregnancies account for about 3.3% of all deliveries in the United States, with most of them being dichorionic diamniotic. Maternal physiological adaptation in twin pregnancies is exaggerated, and the rate of almost every maternal and fetal complication in twin pregnancies is higher than that in singleton pregnancies. Therefore, twin pregnancies necessitate closer antenatal surveillance by care providers, who are familiar with the specific challenges unique to these pregnancies. In addition, there is evidence that following women with twins in a specialized twin clinic can result in improved obstetrical outcomes.
- All pregnant women should be offered screening for aneuploidy. Twin pregnancies present unique challenges in aneuploidy screening. This review describes available aneuploidy screening options and their benefits and limitations in twin pregnancy, along with describing special circumstances, such as vanishing twins and diagnostic testing in twin pregnancy. No method of aneuploidy screening is as accurate in twin pregnancies as singleton pregnancies. Cell-free DNA screening should be considered a first-line approach; however, this option may not be available or may have limitations in certain clinical scenarios, such as vanishing twins.