Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Beth Israel Deaconess Medical Center, Boston, MA; Department of Obstetrics, Gynecology, and Reproductive Biology, Harvard Medical School, Boston, MA.
Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Beth Israel Deaconess Medical Center, Boston, MA; Department of Obstetrics, Gynecology, and Reproductive Biology, Harvard Medical School, Boston, MA.
Am J Obstet Gynecol. 2022 May;226(5):726.e1-726.e9. doi: 10.1016/j.ajog.2021.11.1358. Epub 2021 Nov 26.
Serial growth scans are routinely recommended for twin pregnancies to identify fetal growth restriction (defined as an estimated fetal weight of <10th percentile), which can result in increased perinatal morbidity and mortality. However, the clinical significance of early intertwin growth discordance in the absence of fetal growth restriction remains unclear.
This study aimed to compare the rates of small-for-gestational-age infants among twin pregnancies with intertwin growth discordance in the absence of fetal growth restriction with that among twin pregnancies with concordant, normal growth identified by ultrasound between 24 0/7 and 31 6/7 weeks' gestation.
This was a retrospective cohort study of twin deliveries at a single hospital from 2010 to 2019. Pregnancies without fetal growth restriction were categorized as discordant or concordant using the earliest prenatal growth ultrasound between 24 0/7 and 31 6/7 weeks' gestation. Discordance was defined as an estimated fetal weight difference of ≥18% between twins. Pregnancies with major fetal anomalies, no growth ultrasound between 24 0/7 and 31 6/7 weeks' gestation, or twin-twin transfusion syndrome were excluded. The cohort was stratified by chorionicity. Our primary outcome was small-for-gestational-age defined as <10th percentile per the Fenton growth curve at delivery. Secondary outcomes included gestational age at delivery, mode of delivery, neonatal intensive care unit admission, length of stay, and neonatal complications and placental pathology.
Of the 707 twin pregnancies that met the inclusion criteria, 558 (79%) were dichorionic and 149 (21%) were monochorionic. Most pregnancies were concordant on ultrasound between 24 0/7 and 31 6/7 weeks' gestation (dichorionic, 93%; monochorionic, 87%). Regardless of chorionicity, twin pregnancies with discordance at ultrasound, were more likely to have a small-for-gestational-age infant than concordant twin pregnancies (dichorionic: 51% vs 29%; P=.002; monochorionic: 65% vs 24%; P<.001). Furthermore, women with twin pregnancies with discordance were delivered at an earlier gestational age (dichorionic: 36 weeks [interquartile range, 33-36] vs 34 weeks [interquartile range, 34-38]; P<.001; monochorionic: 34 weeks [interquartile range, 32-34] vs 36 weeks [interquartile range, 34-37]; P=.003). Pregnancies with growth discordance were more likely to be delivered by cesarean delivery (dichorionic: 90% vs 72%; P=.01; monochorionic: 65% vs 60%; P=.70), although this was only statistically significant for dichorionic twin pregnancies. Neonates of pregnancies with growth discordance had a higher incidence of respiratory distress syndrome (dichorionic: 54% vs 37%; P=.04; monochorionic: 70% vs 45%; P=.04) and neonatal intensive care unit admission (dichorionic: 71% vs 50%; P=.01; monochorionic: 90% vs 65%; P=.03). Furthermore, dichorionic infants had longer neonatal intensive care unit stays (30 [interquartile range, 18-61] vs 18 [interquartile range, 10-35] days; P=.02).
Regardless of chorionicity, twin pregnancies with discordance without fetal growth restriction identified on growth ultrasound between 24 0/7 and 31 6/7 weeks' gestation were nearly twice as likely to develop small-for-gestational-age neonates, deliver earlier in gestation, and experience greater neonatal morbidity than twin pregnancies without discordance. Patients with pregnancies complicated by isolated intertwin discordance between 24 0/7 and 31 6/7 weeks' gestation will need counseling regarding adverse perinatal outcomes.
为了识别胎儿生长受限（定义为估计胎儿体重<第 10 百分位），通常建议对双胞胎妊娠进行连续生长扫描，这可能会导致围产期发病率和死亡率增加。然而，在 24 0/7 至 31 6/7 周妊娠期间超声检查无胎儿生长受限的情况下，早期双胎间生长差异的临床意义仍不清楚。
本研究旨在比较在 24 0/7 至 31 6/7 周妊娠期间超声检查无胎儿生长受限的双胎妊娠中，双胎间生长差异与超声检查双胎生长一致的双胎妊娠之间小于胎龄儿的发生率。
这是一项回顾性队列研究，纳入了 2010 年至 2019 年在一家医院分娩的双胎妊娠。在 24 0/7 至 31 6/7 周妊娠期间最早的产前生长超声检查中，使用超声检查将无胎儿生长受限的妊娠分为差异或一致。差异定义为双胞胎之间的估计胎儿体重差异≥18%。排除有主要胎儿异常、24 0/7 至 31 6/7 周妊娠期间无生长超声检查或双胎输血综合征的妊娠。根据绒毛膜性对队列进行分层。我们的主要结局是小于胎龄儿，定义为分娩时根据 Fenton 生长曲线<第 10 百分位。次要结局包括分娩时的胎龄、分娩方式、新生儿重症监护病房入院、住院时间和新生儿并发症及胎盘病理。
在符合纳入标准的 707 例双胎妊娠中，558 例（79%）为双绒毛膜性，149 例（21%）为单绒毛膜性。大多数妊娠在 24 0/7 至 31 6/7 周妊娠期间超声检查结果一致（双绒毛膜性：93%；单绒毛膜性：87%）。无论绒毛膜性如何，在 24 0/7 至 31 6/7 周妊娠期间超声检查有差异的双胎妊娠，其小于胎龄儿的发生率高于一致的双胎妊娠（双绒毛膜性：51% vs 29%；P=0.002；单绒毛膜性：65% vs 24%；P<.001）。此外，双胎间生长差异的孕妇分娩时间更早（双绒毛膜性：36 周[四分位距，33-36] vs 34 周[四分位距，34-38]；P<.001；单绒毛膜性：34 周[四分位距，32-34] vs 36 周[四分位距，34-37]；P=0.003）。生长差异的妊娠更可能通过剖宫产分娩（双绒毛膜性：90% vs 72%；P=0.01；单绒毛膜性：65% vs 60%；P=.70），尽管这在双绒毛膜性双胎妊娠中仅具有统计学意义。生长差异妊娠的新生儿呼吸窘迫综合征发生率更高（双绒毛膜性：54% vs 37%；P=0.04；单绒毛膜性：70% vs 45%；P=0.04）和新生儿重症监护病房入院率更高（双绒毛膜性：71% vs 50%；P=0.01；单绒毛膜性：90% vs 65%；P=0.03）。此外，双绒毛膜性婴儿的新生儿重症监护病房住院时间更长（30[四分位距，18-61] vs 18[四分位距，10-35]天；P=0.02）。
无论绒毛膜性如何，在 24 0/7 至 31 6/7 周妊娠期间超声检查无胎儿生长受限的情况下，双胎妊娠中存在双胎间生长差异，其小于胎龄儿的发生率、分娩时的胎龄和新生儿发病率均高于无差异的双胎妊娠。妊娠期间单纯存在 24 0/7 至 31 6/7 周妊娠期间的双胎间生长差异的患者，需要对不良围产期结局进行咨询。
