Acute and chronic fetal hypoxia in monochorionic and dichorionic twins

Area of Science:

• Perinatal medicine
• Neonatology
• Fetal physiology

Background:

• Twin pregnancies present unique challenges to fetal well-being.
• Assessing risks of acute and chronic fetal hypoxia is crucial for optimal outcomes.

Purpose of the Study:

• To evaluate the risks of acute and chronic fetal hypoxia in twin pregnancies.
• To compare hypoxia markers between firstborn and second-born twins.
• To investigate the influence of gestational age, birth weight, and chorionicity on fetal hypoxia.

Main Methods:

• Umbilical arterial pH and erythropoietin levels were measured in 50 twin sets and 26 singleton controls.
• Infants were categorized as appropriate for gestational age (AGA), small for gestational age (SGA), or large for gestational age (LGA).
• Data were analyzed considering birth order, weight discordancy, and chorionicity (monochorionic vs. dichorionic).

Main Results:

• Second-born twins exhibited lower umbilical arterial pH and a higher incidence of low pH compared to firstborns.
• Elevated erythropoietin concentrations were observed in SGA twins and in smaller twins from discordant pairs.
• Monochorionic twins showed higher erythropoietin levels than dichorionic twins, indicating increased chronic hypoxia risk.

Conclusions:

• The second-born twin is at increased risk for acute birth asphyxia.
• Fetal growth restriction in twin pregnancies is significantly associated with chronic fetal hypoxia.
• Monochorionic twins face a higher risk of chronic fetal hypoxia compared to dichorionic twins.