title: Twins: prevalence, problems, and preterm births.
abstract: The rate of twin pregnancies in the United States has stabilized at 32 per 1000 births in 2006. Aside from determining chorionicity, first-trimester screening and second-trimester ultrasound scanning should ascertain whether there are structural or chromosomal abnormalities. Compared with singleton births, genetic amniocentesis-related loss at <24 weeks of gestation for twin births is higher (0.9% vs 2.9%, respectively). Selective termination for an anomalous fetus is an option, although the pregnancy loss rate is 7% at experienced centers. For singleton and twin births for African American and white women, approximately 50% of preterm births are indicated; approximately one-third of these births are spontaneous, and 10% of the births occur after preterm premature rupture of membranes. From 1989-2000, the rate of preterm twin births increased, for African American and white women alike, although the perinatal mortality rate has actually decreased. As with singleton births, tocolytics should be used judiciously and only for a limited time (<48 hours) in twin births. Administration of antenatal corticosteroids is an evidence-based recommendation.
authors: Aurora Health Care and Center for Urban Population Health, Milwaukee, WI, USA.
authors: Suneet P
authors: SP
authors: Chauhan
authors: James A
authors: JA
authors: Scardo
authors: Edward
authors: E
authors: Hayes
authors: Alfred Z
authors: AZ
authors: Abuhamad
authors: Vincenzo
authors: V
authors: Berghella
mesh_terms: D000649:Amniocentesis; D000650:Amnion / Q000000981:diagnostic imaging; D001723:Birth Rate; D002823:Chorion / Q000000981:diagnostic imaging; D015193:Chorionic Villi Sampling; D002869:Chromosome Aberrations; D000013:Congenital Abnormalities; D005260:Female; D005322:Premature Rupture of Fetal Membranes; D006801:Humans; D007752:Obstetric Labor, Premature / Q000628:therapy; D054238:Perinatal Mortality; D011247:Pregnancy; D011272:Pregnancy, Multiple; D047928:Premature Birth / Q000453:epidemiology / Q000517:prevention & control; D014427:Twins; D016216:Ultrasonography, Prenatal