Reported February 2009

ABOUT MULTIPLE PREGNANCIES: A multiple pregnancy occurs when a woman is carrying multiple fetuses simultaneously. The fetuses may be identical, which are produced from one egg and one sperm before dividing into different fetuses, or fraternal, which are produced by multiple fertilized eggs that develop independently. There are several factors that can increase the likelihood of multiple births, including age, incidence of twins in the family and the use of infertility treatment.

ABOUT THE PLACENTA: The placenta is an organ that develops when a woman is pregnant. It is connected to the fetus by blood vessels via the umbilical cord, which supplies oxygen and nutrients from the mother and transfers waste products produced by the fetus. The placenta also produces hormones and secretes them to the body. In the instance that fetuses from a multiple pregnancy share a single placenta, it is possible for the two developing babies to develop blood vessels that connect through the placenta, allowing blood to pass from one twin to the other. This can cause great danger, as one twin may have low blood volume and inhibited growth while the other may experience high blood volume, which can tax the heart and cause heart failure.

If you would like more information, please contact:

Sharon Boston
Media Relations
University of Maryland Medical Center and
University of Maryland School of Medicine
22 South Greene Street
Baltimore, MD 21201-1595
(410) 328-8919
sboston@umm.edu

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