Complications of Multiple Pregnancy

Dealing with a multiple pregnancy involves more than the economic, emotional, and parental challenges of having several babies at once. There are serious medical risks and complications associated with carrying more than one fetus and giving birth to more than one infant at the same time. A multiple pregnancy is considered high risk; it requires early detection, specialized, extensive clinical management and monitoring, and awareness of possible complications.

Complications for the mother and infant can be very serious, and the risks increase with the number of fetuses.

Maternal Risks and Complications

Multiple fetuses pose health risks to the mother that can compromise her pregnancy and childbirth. In a multiple pregnancy, fetal requirements are proportionately greater and maternal blood volume is approximately 500 mL greater than in a singleton pregnancy. Prenatal (before birth) screening and care is critical in order to detect complications early so they can be properly managed.

Miscarriages—They are at least twice as common in multiple pregnancies.

Hyperemesis gravidarum—"Morning sickness" is common in multiple pregnancies and is characterized by excessive nausea and vomiting.

Pregnancy-induced high blood pressureHypertension is 3 times more common in multiple pregnancies, and it is more severe.

Increased incidence of preeclampsia—This is a toxic condition that can develop in late pregnancy. It is characterized by a sudden rise in blood pressure, excessive weight gain, swelling, severe headache, visual disturbances, and excessive protein in the urine (proteinuria). Severe preeclampsia can be life threatening.

Gestational diabetes—This form of diabetes develops for the first time during pregnancy as a result of hormones produced by the placenta. The condition usually subsides after delivery.

Iron- and folate-deficiency anemias—It is generally recommended that women take 60–80 mg of iron and 1 mg of folic acid supplementation daily to prevent anemia. A high-protein diet is also recommended.

Acute polyhydramnios—An excessive amount of amniotic fluid, the liquid inside the sac that holds the fetus, occurs in about 5 - 8% of women who have a multiple pregnancy.

Vaginal and uterine hemorrhaging—This condition is characterized by antepartum (before childbirth) heavy or uncontrollable bleeding.

Preterm labor and delivery—The average length of pregnancy is 39 weeks for singletons, 35 weeks for twins, 33 weeks for triplets, and 29 weeks for quadruplets. Multiple pregnancy is, on average, 12 times more likely to be preterm. Preterm labor often requires prolonged bed rest or hospitalization. Generally, once the pregnancy reaches about 32 weeks, the complications associated with premature delivery are significantly reduced.

Prolonged hospitalization and surgical delivery (i.e., caesarian section)—Caesarian section is often necessitated by malpresentation (abnormal position of the fetuses) that makes a vaginal delivery difficult, if not impossible.

Publication Review By: Stanley J. Swierzewski, III, M.D.

Published: 01 Nov 2000

Last Modified: 23 Aug 2011