Antenatal Surveillance in Twin Pregnancies Using the Biophysical Profile

Abstract

Objectives The nonstress test is currently the most widely used modality for antenatal surveillance in twin pregnancies, with a quoted false‐positive rate of 11%–12%. Our objective was to report our experience with the sonographic portion of the biophysical profile in twin pregnancies as the primary screening modality. Methods Women with twin pregnancies delivered by a single maternal‐fetal medicine practice from 2005 to 2013 were included. We excluded monoamniotic twins. Twin pregnancies began weekly sonography for the biophysical profile starting at 32 to 33 weeks, or earlier if indicated. The nonstress test was performed if the sonographic biophysical profile score was less than 8 of 8. We reviewed biophysical profile scores and outcomes for all patients who delivered at 33 weeks or later to assess the false‐positive rate for the biophysical profile, as well as the incidence of intrauterine fetal death (IUFD) after initiation of antenatal surveillance. Results A total of 539 twin pregnancies were included. The incidence of IUFD per patient was 2 per 539 (0.4%; 95% confidence interval [CI], 0.1%–1.3%), and the incidence of IUFD per fetus was 2 per 1078 (0.19%; 95% CI, 0.05%–0.7%). The overall positive screen rate was 24 per 539 (4.45%; 95% CI, 3.0%–6.5%). The false‐positive screen rate, defined as an abnormal biophysical profile that did not diagnose an IUFD or lead to delivery, was 10 per 539 (1.9%; 95% CI, 1.0%–3.4%). Conclusions—In twin pregnancies the use of the sonographic biophysical profile for routine antenatal surveillance has a low false‐positive rate, with a very low incidence of IUFD. The sonographic biophysical profile should be considered as a primary mode for antenatal surveillance in twin pregnancies, with a reflex nonstress test for an abnormal score.

Multifetal Gestations: Twin, Triplet, and Higher-Order Multifetal Pregnancies

“…In dichorionic twins, stillbirth rates were as follows: c 0.8 per 1,000 at 35 0/7 to 35 6/7 weeks c 1.5 per 1,000 at 36 0/7 to 36 6/7 weeks c 3.4 per 1,000 at 37 0/7 to 37 6/7 weeks c 10.6 per 1,000 at 38 0/7 to 38 6/7 weeks In monochorionic diamniotic twins the stillbirth rates were as follows: c 0.9 per 1,000 at 34 0/7 to 34 6/7 weeks c 2.8 per 1,000 at 35 0/7 to 35 6/7 weeks c 4.5 per 1,000 at 36 0/7 to 36 6/7 weeks c 9.6 per 1,000 at 37 0/7 to 37 6/7 weeks The optimal gestational age for initiation of surveillance in pregnant individuals with uncomplicated dichorionic twins is not known. However, for patients with uncomplicated dichorionic twin pregnancies, weekly antenatal fetal surveillance may be considered at 36 0/7 weeks of gestation (114)(115)(116). For patients with a dichorionic twin pregnancy complicated by maternal or fetal disorders such as fetal growth restriction, antenatal fetal surveillance should be individualized and may be considered upon diagnosis, or at a gestational age after which delivery would be considered for abnormal testing (117).…”

“…Because of higher stillbirth risks in monochorionicdiamniotic twins and the potential for severe clinical consequences for the surviving twin, initiation of antenatal fetal surveillance is typically recommended at 32 0/7 weeks of gestation (114)(115)(116).…”

“…The optimal gestational age for initiation of surveillance in pregnant individuals with uncomplicated dichorionic twins is not known. However, for patients with uncomplicated dichorionic twin pregnancies, weekly antenatal fetal surveillance may be considered at 36 0/7 weeks of gestation (114–116). For patients with a dichorionic twin pregnancy complicated by maternal or fetal disorders such as fetal growth restriction, antenatal fetal surveillance should be individualized and may be considered upon diagnosis, or at a gestational age after which delivery would be considered for abnormal testing (117).…”

Indications for Outpatient Antenatal Fetal Surveillance

“…Because of higher stillbirth risks in monochorionicdiamniotic twins and the potential for severe clinical consequences for the surviving twin, initiation of surveillance is typically recommended at 32 0/7 weeks of gestation (22)(23)(24). Implementation of such protocols has resulted in stillbirth rates in monochorionic-diamniotic twins similar to those of dichorionic-diamniotic twins (23,24) and has lowered the rates of stillbirth in monochorionic-diamniotic twins to be comparable to those seen in singletons at similar gestational ages (22)(23)(24). Such protocols of surveillance result in negligible false-positive rates (1.9%; 95% CI, 1.0%-3.4%) (22).…”

Hemolytic Disorders of the Newborn, Current Methods of Diagnosis and Treatment: A Review Study

“…• Intravascular transfusion -blood transfused into fetal umbilical vein [55] • Early delivery (usually after about 36 wks gestation) If the fetus has mature lungs, labor and delivery may be induced to prevent worsening of hemolytic disease of the newborn Ultrasonography in biophysical profile: Biophysical Profile (BPP) is a prenatal ultrasound evaluation of fetal well-being involving a scoring system. BPP has become a standard tool for providing antepartum fetal surveillance [56]. The Biophysical Profile (BPP) is a noninvasive test that predicts the presence or absence of fetal asphyxia and ultimately the risk of fetal death in the antenatal period [57].…”