3. Special Issues for Identical Twins
With monozygotic (identical) twins,
division of the fertilized egg occurs between the first few days and
about day 8. If division of the egg occurs after 8 days, the result can
be twins that are connected, called conjoined twins. (Conjoined twins used to be called Siamese twins.) These babies may share important internal organs, such as the heart, lungs or liver. Fortunately this is a rare occurrence.
Identical twins may face some risks. There is a 15% chance they will develop a serious problem called twin-to-twin transfusion syndrome. There is one placenta, and the babies’ blood vessels share the placenta. The problem arises when one baby gets too much blood flow and the other too little.
With monozygotic twins, there is a chance
several different types of diseases may occur in both twins during
their lifetimes. This is less likely to happen with dizygotic twins.
Due to health concerns, it may be
important later in life for your children to know whether they were
monozygotic or dizygotic. Before delivery, tell your doctor you would
like to have the placenta(s) examined (with a pathology exam) so you
will know whether your babies were monozygotic or dizygotic. It may be
valuable information in the future. Even if there are two placentas,
research shows it doesn’t mean twins are dizygotic; nearly 35% of all
monozygotic twins have two placentas.
If you have already given birth to a set
of fraternal twins, your chance of having another set of twins
quadruples! Other reasons for multiple fetuses include some women
having more children, being very tall or obese, recently discontinuing
oral contraception or taking large doses of folic acid. Studies have
shown the twin birth rate for women who took folic acid can be as high
as double the rate of women who did not take large doses of folic acid.
Having more children (or pregnancies) can
also result in more than one baby. This is true in all populations and
may be related to the mother’s age and female hormone changes.
4. Discovering a Multiple Pregnancy
Diagnosis of twins was more difficult
before ultrasound was available. However, most multiple pregnancies are
discovered well before delivery. Today, it’s uncommon to discover twin
pregnancies just by hearing two heartbeats. Many people believe when
only one heartbeat is heard, there could be no possibility of twins.
This may not be the case. Two rapid heartbeats may have a similar or
almost identical rate. That could make it difficult to determine that
there are two babies.
Measuring and examining your abdomen
during pregnancy is important. A healthcare provider usually finds out
a woman is carrying more than one baby because she has a
larger-than-expected uterus. Usually a twin pregnancy is noted during
the second trimester because you are too big and growth seems too fast
for a single pregnancy. Other signs include more severe nausea and/or
vomiting, and hearing more than one fetal heartbeat.
Ultrasound examination is the best way to diagnose a multiple pregnancy.
5. Increased Risks Associated with a Multiple Pregnancy
If a woman is pregnant with more than
one baby, her risk of problems during pregnancy increases. You can
minimize your risks, and possibly avoid them, with good prenatal care
and careful attention to your health. Possible pregnancy problems
include the following:
•increased risk of miscarriage
•fetal death
•fetal malformations
•low birthweight or growth restriction
•pre-eclampsia
•problems with the placenta, including placental abruption and placenta previa
•maternal anemia
•maternal bleeding or hemorrhage
•problems with the umbilical cords, including entwinement or tangling of the babies’ umbilical cords
•hydramnios or polyhydramnios
•labor complicated by abnormal fetal presentation, such as breech or transverse presentation
•premature labor
•difficult delivery and Cesarean delivery
Birth defects are more common with
identical twins than fraternal twins. The incidence of minor
malformations in a multiple pregnancy is twice as high as it is in a
singleton pregnancy, and major malformations are also more common.
One of the biggest problems with multiple
pregnancies is premature delivery. As the number of fetuses increases,
the length of gestation and the birth-weight of each baby decreases,
although this is not true in every case.
The average length of pregnancy for twins
is about 37 weeks. For triplets it is about 35 weeks. For every week
the babies remain in the uterus, their birth-weights increase along
with the maturity of organs and systems.
It’s important to continue your pregnancy
as long as possible, which may best be accomplished by bed rest. You
may not be able to carry on with regular activities during your entire
pregnancy. If your healthcare provider recommends bed rest, follow his
or her advice.
Weight gain is important with a multiple
pregnancy. You will probably be advised to gain more than the normal 25
to 35 pounds, depending on the number of fetuses
you are carrying. With twins, if you were normal weight before
pregnancy, you may be advised to gain 40 to 54 pounds (18 to 24.5 kg).
For overweight women, a weight gain between 31 and 50 pounds (14 to
22.7 kg) may be recommended. A weight gain between 25 and 42 (11.3 to
19 kg)pounds may be recommended for obese women. If you’re expecting
triplets, your weight gain will probably be between 50 and 60 pounds
(22.7 to 27.2 kg) if you are normal weight before pregnancy.
Pay strict attention to your eating plan;
eat wisely and nutritiously for all of you. Extra rest is essential.
Most pregnant women need at least 2 hours of extra rest each day.
When you’re pregnant with more than one
baby, you will probably be monitored more closely. You may have more
frequent checkups and more tests.
Beginning around 20 weeks of pregnancy,
you will probably visit your healthcare provider every other week until
week 30. Then you may be seen once a week until delivery. You may have
ultrasound more frequently to monitor babies’ growth. Your blood
pressure is watched closely because of preeclampsia, which is twice as
common in multiple pregnancies.
Follow your doctor’s instructions
closely. Every day and every week you’re able to keep the babies inside
you are days or weeks you won’t have to visit them in an intensive-care
nursery while they grow, develop and finish maturing.
