Monisikiöraskaus

Monisikiöraskaus, commonly referred to as multiple gestation, is a pregnancy involving more than one fetus. The most common form is twins, followed by triplets and higher-order multiple births. Multiples arise mainly from dizygotic twinning (two separate eggs fertilized) and, less commonly, from monozygotic twinning (one egg splits). Assisted reproductive technologies and increasing maternal age raise the likelihood of multiple pregnancies. Classification is by number of fetuses and by placental/amnionic configuration: dichorionic-diamniotic twins (two placentas, two amniotic sacs), monochorionic-diamniotic twins (one placenta, two sacs), and monochorionic-monoamniotic twins (one placenta, one amniotic sac).

Multiple gestations carry higher risks for the mother and fetuses. Maternal risks include anemia, gestational diabetes, hypertensive disorders, and a higher chance of cesarean delivery. For fetuses, increased risk of preterm birth, low birth weight, growth discordance, and, in monochorionic pregnancies, twin-to-twin transfusion syndrome. Congenital anomalies are more common with higher-order multiples. Careful monitoring is essential.

Diagnosis is typically made by ultrasound in early pregnancy and repeated to assess fetal number, chorionicity, and growth. Management involves specialized prenatal care with frequent visits and targeted ultrasound, fetal surveillance, and planning of delivery. Antenatal corticosteroids may be given if early delivery is anticipated. The timing and mode of delivery depend on the number of fetuses, chorionicity, and maternal/fetal health; vaginal delivery may be possible in selected twin pregnancies, while many twins are delivered by cesarean section.

With modern obstetric care, many babies from multiple pregnancies survive, though outcomes are generally less favorable than for singleton pregnancies, particularly in twins or higher-order multiples.