Neonatal Morbidity of Monoamniotic Twin Pregnancies: A Systematic Review and Meta-analysis

Objective ?This study was aimed to report the incidence of neonatal morbidity in monochorionic monoamniotic (MCMA) twin pregnancies according to gestational age at birth and type of management adopted (inpatient or outpatient). Study Design ?Medline and Embase databases were searched. Inclusion criteria were nonanomalous MCMA twins. The primary outcome was a composite score of neonatal morbidity, defined as the occurrence of at least one of the following outcomes: respiratory morbidity, overall neurological morbidity, severe neurological morbidity, and infectious morbidity, necrotizing enterocolitis at different gestational age windows (24-30, 31-32, 33-34, and 35-36 weeks). Secondary outcomes were the individual components of the primary outcome and admission to neonatal intensive care unit (NICU). Subanalysis according to the type of surveillance strategy (inpatient compared with outpatient) was also performed. Random effect meta-analyses were used to analyze the data. Results ?A total of 14 studies including 685 MCMA twin pregnancies without fetal anomalies were included. At 24 to 30, 31 to 32, 33 to 34, and 35 to 36 weeks of gestation, the rate of composite morbidity was 75.4, 65.5, 37.6, and 18.5%, respectively, the rate of respiratory morbidity was 74.2, 59.1, 35.5, and 12.2%, respectively, while overall neurological morbidity occurred in 15.3, 10.2, 4.3, and 0% of the cases, respectively. Infectious morbidity complicated 13, 4.2, 3.1, and 0% of newborns while 92.1, 81.6, 58.7, and 0% of cases required admission to NICU. Morbidity in pregnancies delivered between 35 and 36 weeks of gestation was affected by the very small sample size of cases included. When comparing the occurrence of overall morbidity according to the type of management (inpatient or outpatient), there was no difference between the two surveillance strategies (p = 0.114). Conclusion ?MCMA pregnancies are at high risk of composite neonatal morbidity, mainly respiratory morbidity that gradually decreases with increasing gestational age at delivery with a significant reduction for pregnancies delivered between 33 and 34 weeks. We found no difference in the occurrence of neonatal morbidity between pregnancies managed as inpatient or outpatient. Key Points MCMA pregnancies are at high risk of composite neonatal morbidity, mainly respiratory morbidity. Neonatal morbidity gradually decreases with increasing GA at delivery, mostly between 33 and 34 weeks. There is no difference in the occurrence of neonatal morbidity between in- or outpatient management.