Twin+Pregnancy+Surveillance

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** Prenatal Guideline ** Consultation available 24 hours per day from OB on-call at 925-370-5608 or via page/amion, via inbasket to OB dept member or by calling Perinatologist at 510-444-0790 during the day and 510-204-1572 after hours. Consultation appointments or transfer of care to more experienced prenatal clinician available at major clinics sites—see consultation guidelines for more information.

**Prenatal Surveillance of Twin Pregnancies** __**General Care**__ Women with a twin pregnancy are at increased risk for preelampsia, gestational diabetes, anemia, preterm delivery, and postpartum depression. Prenatal care should include monitoring for these conditions and educating patients regarding relevant symptoms. Using the clinic’s ultrasound rather than the doppler to identify presence of both fetal heart rates in clinic is recommended if available. Interventions to prevent preterm labor in patients without a prior preterm birth such as progesterone, cerclage or bedrest are **not** recommended. Prenatal clinicians without recent twin experience should review their care plan with an Obstetric Attending by phone or inbasket query, or transfer care to a more experienced prenatal physician. Perinatology consultation is available by phone, referral or consultation clinics for when there are concerning findings. (See prenatal consultation) Ultrasound should be used to establish chorionicity (number of placentas) and number of amniotic sacs early in pregnancy. This can be established during the early dating ultrasound, the NT ultraound, or the anatomy ultrasound. The type of twin gestation should be displayed on the problem list. Chorionicity is more accurate in the first or early second trimester.

__**Dichorionic Diamniotic Twins**__ (most common, lower risk)


 * Anatomy ultrasound at about 20 weeks EGA
 * Growth ultrasounds every 4 weeks starting at 24-26 weeks (be sure to order in advance as these take longer than singleton ultrasounds and are more difficult to schedule).
 * If concordant growth (within 20%) and both twins > 10% on singleton growth chart start antepartum testing 36 weeks EGA with biweekly NST and q week fluid assessment.
 * If discordant growth (difference over weight bigger twin > 20%) or one or both twins < 10% on singleton Hadlock growth chart start monitoring when identified or per consultation. Less risk if both AGA even if discordant. Order umbilical artery doppler weekly for any twin < 10% for gestational age. Ultrasounds may be more often and delivery recommended earlier than 38 weeks, depending on monitoring results and follow up ultrasound results.
 * If concordant we recommend delivery scheduled in the 38th week with induction for vertex/vertex and cesarean if presenting twin A is not vertex. If presenting twin A vertex and second breech or transverse delivery route is per patient preference—consult CCRMC OB Attendings for more information.


 * __Monochorionic Diamniotic Twins__** (less common, higher risk for adverse outcome)-- Consult for surveillance plan as soon as diagnosed


 * Anatomy ultrasound, level II preferred, at 18 weeks EGA
 * Serial growth/fluid assessment ultrasounds every 2-3 from 16 weeks gestation. These twins are at risk for twin/twin transfusion syndrome in early gestation manifested by discordant growth, and oligohydramnios of smaller twin. Fetal surgery may be considered before 24 weeks if this is identified, to try to prevent fetal loss. Late manifestations of twin-twin transfusion can also occur even if growth early is reassuring.
 * Antepartum testing with biweekly NSTs and q week fluid assessment should start at 32 weeks. If discordant or either < 10% consult Perinatology for frequency of ultrasounds, possible earlier antepartum testing, umbilical artery dopplers and timing of delivery.
 * If concordant, AGA growth delivery should occur at 37 weeks EGA by induction or cesarean depending on fetal position and preference of the mother.


 * __Monochorionic Monoamniotic Twins__** (very rare and very high risk)

Order level II ultrasound when identified to verify monoamniotic—this is urgent if > 23 weeks or discordant/growth restricted. Consult Perinatology for plan for surveillance plan and timing of transfer of care to Perinatology. These women are usually admitted to the hospital at about 28 weeks EGA for intensive monitoring and delivered by 32-34 weeks.

__**Fetal Demise of One Twin**__

__Dichorionic Diamniotic__ Generally does not impact the other twin unless maternal condition cause of loss. Will then continue prenatal care as a singleton. If over 24 weeks send to L and D to assess remaining twin.

__Monochorionic Diamniotic__ Send immediately to labor and delivery for assessment if > 23 weeks EGA. Consult Perinatology if < 23 weeks. Second twin often has immediate adverse sequelae or death.