Outcomes in intervention and management of multiple pregnancies trials: A systematic review

Nearly 0.7%-3.34% of women experience multiple pregnancies globally. This variation is mainly due to increased use of assisted reproductive techniques, maternal age and parity leading to a rise in dizygotic, and to a lesser extent monozygotic, twinning. 

Twin pregnancy may cause adverse outcomes for mother and baby. Data synthesis is needed to accumulate evidence to aid recommendations but they may be impeded by variations in outcome reporting.

A recent study searched MEDLINE, EMBASE, CINHAL, and Cochrane library (inception-January 2019) for randomized control trials or their follow-up studies reporting prediction, prognosis, intervention or management outcomes in twin pregnancy. The data were extracted and descriptively analyzed.

The observations were as follows-

• The study included 49 RCTs and 8 follow-up studies that evaluated 21 interventions, and 1257 outcomes, categorized into 170 unique outcomes. 
• 65 % of trials incorporated all twin pregnancies, 12 % DCDA (dichorionic/diamniotic) and 11 % MCDA (monochorionic/diamniotic) only or MCMA (monochorionic/monoamniotic) and MCDA.
• 9 % of the papers were prediction/ prognosis RCTs and 91 % were related to the intervention. 
• Of interventions, 77 % were medical, 85 % for preterm birth; 23 % surgical, 50 % related to TTTS interventions (83 % for monochorionic studies). 
• The commonest domains were found to be: ‘Neonatal’ 77 %, ‘Delivery’ 70 % and ‘Survival’ 67 %. while the least reported were longer-term outcomes for ‘Infant’ or ‘Parental’.

Thus, twin pregnancies have diverse and complex outcomes, which are related to the need to address maternal, single and double fetal outcomes and different types of chorionicity. The absence of outcome standardization in selection, definition and reporting interferes with evidence synthesis and the selection of outcomes, which are crucial for women and health care professionals. This further limits the effectiveness of research.

Source: Farmer N, Hillier M, Kilby MD, Hodgetts-Morton V, Morris RK. Outcomes in intervention and management of multiple pregnancies trials: A systematic review. European Journal of Obstetrics & Gynecology and Reproductive Biology. 2021;261:178-192. DOI:https://doi.org/10.1016/j.ejogrb.2021.04.025