Multiple Gestation

Plan for hemorrhage before delivery - Uterine distension from a multifetal gestation is a recognized risk factor for uterine atony, and atony causes 70% to 80% of postpartum hemorrhage. Multiple gestation alone puts the patient in the medium-risk group, so type and screen; with two or more medium-risk factors, type and cross. Large-bore access and uterotonics ready before the placenta is out.

Left uterine displacement every time - The gravid uterus compresses the inferior vena cava and aorta in the supine position after 20 weeks. Tilt 15 to 30 degrees to the left, or manually shift the uterus off the cava with a hand on the right side of the abdomen. Manual displacement takes no equipment and works during CPR.

Preeclampsia surveillance - Blood pressure and urine protein at every prenatal visit; the risk is higher than in singleton pregnancy. Look at the trend, not one reading.

Check the glucose screen - Gestational diabetes is more common with a doubled placental mass. Review the glucose tolerance result and get a point-of-care glucose on arrival.

Expect preterm delivery - Preterm birth is the dominant risk in twin gestations, so plan for a preterm neonate and a neonatal team in the room.

Magnesium cuts both ways - If she is on a magnesium sulfate infusion, that infusion is itself a risk factor for uterine atony. Do not relax about bleeding because the pressure looks controlled.

Monochorionic twins need surveillance - Shared placental vessels can produce TTTS: the recipient develops polycythemia, polyhydramnios, and hydrops, the donor oligohydramnios and severe anemia. Untreated TTTS presenting before 26 weeks carries 60% to 80% fetal mortality. Fetoscopic laser photocoagulation of the communicating vessels is the definitive treatment for severe cases and has been managed under epidural anesthesia.

Anemia after the bleed - Postpartum anemia is common after atony-related hemorrhage, and the iron lost is not fully replaced by transfused blood. Follow the hemoglobin and flag the patient for oral or parenteral iron rather than assuming the transfusion settled it.

Multiple gestation is a pregnancy carrying two or more fetuses. Twins make up about 3% of US live births, and dizygotic twins account for roughly 70% of twin gestations. Chorionicity, not zygosity, drives the risk: monochorionic placentas carry vascular connections between the two fetal circulations, which can produce twin-twin transfusion syndrome (TTTS) and twin anemia-polycythemia sequence.

Doubling the placental mass raises the incidence of preeclampsia, gestational diabetes, and placenta previa, while the overdistended uterus predisposes to preterm labor and to postpartum uterine atony. Aortocaval compression from the gravid uterus after 20 weeks limits venous return and placental flow, and with uterine blood flow reaching roughly 600 mL/min at term, even a modest fall in preload shows up quickly as fetal compromise.