More and more people are having twins these days, and there are some unique challenges for moms who are carrying more than one baby during their pregnancy. If you are carrying more than two babies, your provider will fill you in on the specific tests and precautions that will apply to your special pregnancy.
Twin pregnancies are considered higher risk and they warrant special testing and closer monitoring. They are associated with an increased risk of most pregnancy complications, including, but not limited to: preterm labor, preterm delivery, premature rupture of membranes, intrauterine growth restriction, pregnancy-induced hypertension, preeclampsia, and gestational diabetes.
However, with advanced technology available to care for premature infants, most twins not only survive, they thrive!
Your provider will discuss the risks of a twin pregnancy with you as soon as the diagnosis is made. Often this is on routine ultrasound in the second trimester or when your uterus feels larger than expected for a single baby.
There are two basic types of twins: fraternal twins and identical twins. Fraternal twins are created when two different sperm fertilize two different eggs, usually during the same menstrual cycle. This phenomenon is more common in African Americans than in Caucasians, and in Caucasians more than in Asians. Having fraternal twins can also be hereditary, or a result of fertility treatment. It is also more common in older women and in those who have previously conceived.
Identical twins occur as a random event and are not associated with race or family history or age. They are less common and occur only once in about every 250 births. One egg is fertilized and splits in the early days of rapid cell multiplication and division. If this split occurs in the first 3 days of life, then both babies have their own 2 membranes (amnion and chorion). If the split occurs between the 4th and 8th days of life, the babies are divided by 1 membrane known as the amnion. Having either one or two dividing membranes protects the umbilical cords from getting tangled around each other. A set of identical twins with no amnion or chorion between them can be more risky. These occur when the fertilized embryo splits 8-12 days after conception. Siamese twins result when the division occurs later than 12 days. These twins are literally attached to each other.
You will need to consume 300 additional calories each day to nourish your twins. Taking your prenatal vitamins is especially important to provide the iron and folic acid your twins need. Your provider will watch your weight gain carefully and encourage you to gain 35-45 pounds, not 25-35 as for a single pregnancy.
Beyond twenty-four weeks, the growth of your twins will be followed carefully. Your ultrasounds will most likely begin every 4 weeks, starting between 24 and 28 weeks. At each ultrasound, measurements will be taken of the head circumference or diameter, the abdominal circumference, and the femur lengths of each twin. These are plugged into a mathematical calculation and used to estimate the weight of each twin. After all, a provider measuring your abdomen doesn't know how much mass belongs to each twin. It is important that both are gaining weight at similar rates.
After 32 weeks in your pregnancy with twins, your provider may want to give you a "Nonstress" test to check the well-being and position of your babies. Most twins are delivered by 38 weeks. If you haven't gone into labor by 38 weeks, your provider may recommend that labor be induced to minimize the risks to your twins.