Possible maternal complications of multiple pregnancy include:

• Miscarriage.
• Anemia.
• Urinary tract infection (UTI).
• High blood pressure and organ damage (preeclampsia).
• Excessive bleeding (hemorrhage).
• Increased chance of cesarean delivery.
• Too much amniotic fluid (polyhydramnios).
• Problems with the placenta, such as placenta abruptio or placenta previa.

Common fetal complications of multiple pregnancy include:

• Increased chance of giving birth before 37 weeks (premature delivery), which poses greater risks of illness, disability, and death. For more information, see the topics Preterm Labor and Premature Infant.
• Vanishing twin syndrome.

Less common fetal complications include:

• Differences in size between the fetuses (discordance), usually from twin-to-twin transfusion. In twin-to-twin transfusion, blood shifts from one fetus (the donor) through the placenta to the other fetus (the recipient).
• Increased risk of birth defects and genetic disorders. For more information, see the topic Multiple Pregnancy: Twins or More.

The delivery and care of multiple infants is costly, especially if they have special needs, which often is the case with babies born prematurely.

If a woman becomes pregnant with several fetuses, she and her partner may choose selective reduction (multifetal pregnancy reduction). This procedure removes one or more of the embryos during the first trimester, giving the remaining fetuses a better chance of healthy survival. However, the procedure also has a minimum 10% risk of ending the pregnancy.¹