Selective Fetal Growth Restriction in Monochorionic Twins - an International Investigation

Selective fetal growth restriction (sFGR) in monochorionic twins may negatively impact the pregnancy. There is a substantial risk of fetal deterioration resulting in (iatrogenic) preterm birth or even intrauterine demise of one, or both fetuses. There are important unresolved challenges on a diagnostic level and underlying pathophysiological mechanisms of sFGR have not been fully clarified.

The current diagnostic classification system based on three different umbilical artery flow patterns has no increasing scale of severity and the observed flow patterns may be volatile in nature. This hinders optimal diagnostic management and complicates outcome prediction as the survival outcome differs per umbilical artery flow type. Consequently, parents encounter a great deal of uncertainty during the pregnancy. Since there is no treatment available for sFGR, predicting fetal deterioration is key in preventing single or double demise.

By testing several predictors, the investigators are aiming to improve outcome prediction at the time of sFGR diagnosis. The investigators furthermore hypothesize that additional ultrasound parameters could be of benefit in making the current classification system more accurate and less variable. Extensive histological placental examinations will shine a light on microscopic abnormalities which can increase our knowledge of the pathophysiology. Examining neurodevelopment of sFGR twins at two years of age will additionally be of great value for our understanding of the impact of sFGR and contribute to adequate patient counselling. Our study will evaluate the impact of a sFGR pregnancy on parental mental health and parent-to-infant(s) attachment, which has not been carried out this extensively before.

Inclusion criteria

• MCDA twin pregnancy
• Diagnosis of sFGR before 28+0 weeks of GA (independent of Doppler flows)
• Pregnant woman ≥ 18 years and able to consent
• Partner (who has (future) parental responsibility - if applicable) ≥ 18 years and able to consent
• Written informed consent of both parents (if applicable) for participation in the longitudinal follow-up until 2 years after birth)

Exclusion criteria

• The presence of lethal anomalies (one or both fetuses)
• Multiple pregnancy higher order than twins;
• TTTS/TAPS present at moment of sFGR diagnosis.