Looking around at families, have you noticed an increase in multiples? You are not alone. According to the Center for Disease Control (CDC), the rate of twins in the United States has increased some 76 percent since 1980.
This is being attributed to women waiting until their thirties to have children, which carries an increased risk for twins and for more women using fertility assistance.
There are two types of twins. Identical twins occur when one fertilized egg splits and is nourished by a shared placenta whereas fraternal twins occur when two fertilized eggs implant and are nourished by two separate placentas. Male-female twins (fraternal, of course) are the most common type of twins though same sex fraternal twins also occur.
Many women undergoing fertility assistance take certain medications that increase the chance of twins (or more) because multiple eggs are released from the ovary at ovulation and can become fertilized.
During In-vitro fertilization (IVF), multiple fertilized eggs are implanted into the uterus in the hope that one (or more) will take hold and grows into a healthy baby.
However, many reproduction centers have limits on the number of fertilized eggs a woman can have implanted in light of the woman known as ‘octo-mom’ who gave birth to eight babies from IVF.
There are some risks to carrying twins. First, carrying two babies puts increased demand on the mother’s body that may require her to go on bed rest, or be severely limited in her activities earlier than normal. She is also at an increased risk for gestational diabetes, preeclampsia, and high blood pressure.
Second, many twins are smaller weight and deliver pre-term. Third, over 90 percent of twins are born via c-section.
Many want to know about the genetics of multiple births. If twins exist on the mom’s side of the family, then she has a slightly increased chance of having twins.
There doesn’t appear to be any influence from the father as twins require an egg that splits or two fertilized eggs. If a woman has had twins before, her chance of having twins again is increased as much as four times.