Prenatal Health — Twins
Twin pregnancies require additional surveillance including ultrasounds and fetal heart rate monitoring.
In the first trimester, ultrasounds will determine whether they inhabit separate amniotic sacs or share one. The most common twin situation is dichorionic-diamniotic, where they have separate sacs and separate placentas. For those uncommon pregnancies with monoamniotic-monochorionic twins (sharing a sac and placenta), a transfer of care to a high-risk obstetrician (perinatologist) is recommended.
In the second trimester, ultrasounds are performed to assess fetal anatomy and their individual growth rates. These ultrasounds are often provided by the perinatologists acting as consultants. We are watchful for signs of preterm labor as the pregnancy advances and may restrict a woman's activity accordingly.
In the third trimester, ultrasounds continue to monitor fetal growth and additionally monitor for fetal stress. In some cases, extended monitoring of their heart rates is necessary. We continue to monitor for signs of preterm labor. Route of delivery is individualized by the position of the first twin and a review of risks and benefits with the couple. Although we have 8 physicians who assist deliveries, we often suggest to patients with twin pregnancies that you concentrate on 2 physicians to manage your care.