Triplets could also occur if one of two zygotes divide in half. This would mean that two of the triplets would be genetically identical while the third child is considered a fraternal multiple. Similar scenarios occur in quadruplets and other forms of multiples.
How Do Multiple Births Occur? Which category do higher-order multiples triplets, quadruplets, etc. Can I get pregnant if…? Share this post:. Share on facebook Facebook. Share on twitter Twitter. Depending on when the division occurs, identical twins may have separate placentas and gestational sacs, or they may share a single placenta but have separate sacs.
In rare cases, identical twins may be in the same amniotic sac. Non-identical twins occur when two separate eggs are each fertilized by a separate sperm. The two embryos that result are dizygotic, not genetically identical, and can be the same or different sex. Most of the time, this is the type of twinning that occurs from assisted reproduction procedures.
Spontaneous losses are even higher in triplet and quadruplet pregnancies. When a fetus is lost in the first trimester, the remaining fetus or fetuses generally continue to develop normally, although vaginal bleeding may occur.
Ultrasound examinations performed early in the 5th week of pregnancy occasionally may fail to identify all fetuses. After 6 to 8 weeks, ultrasound should provide an accurate assessment of the number of fetuses.
Naturally, twins occur in about one in pregnancies, triplets in about one in 10, pregnancies, and quadruplets in about one in , pregnancies. The main factor that increases your chances of having a multiple pregnancy is the use of infertility treatment, but there are other factors.
Your race, age, heredity, or history of prior pregnancy does not increase your chance of having identical twins but does increase your chance of having fraternal twins. Infertility treatment increases your risk of having twins, both identical and fraternal. The overall rate of twins for all races in the United Statees is around 33 per 1, live births. Black and non-Hispanic white women have similar rates of twinning, while Hispanic women are less likely.
Non-identical twin women give birth to twins at the rate of 1 set per 60 births. However, non-identical male twins father twins at a rate of 1 set per births. Maternal age and prior pregnancy history. The frequency of twins increases with maternal age and number of pregnancies. Women between 35 to 40 years of age with 4 or more children are 3 times more likely to have twins than a woman under 20 without children. Maternal height and weight. Non-identical twins are more common in large and tall women than in small women.
This may be related more to nutrition than to body size alone. During World War II, the incidence of non-identical twinning decreased in Europe when food was not readily available.
Fertility Drugs and Assisted Reproductive Technology. Multiple pregnancy is more common in women who utilize fertility medications to undergo ovulation induction or superovulation. Use of drugs to cause superovulation has caused the vast majority of the increase in the multiples. Assisted reproductive technology ART procedures such as in vitro fertilization IVF also contribute to the increase in the multiple birth rate. The risk of multiple pregnancy increases as the number of embryos transferred increases.
The duration of a normal singleton pregnancy ranges from 37 weeks to 42 weeks from the time of the last menstrual period. Twin pregnancies occasionally progress to 40 weeks but almost always deliver early.
As the number of fetuses increases, the expected duration of the pregnancy decreases. The average duration is 35 weeks for twins, 33 weeks for triplets, and 30 weeks for quadruplets. Complications increase with each additional fetus in a multiple pregnancy and include many medical issues that will be discussed below.
In addition to these, there is a higher incidence of severe nausea and vomiting, cesarean section, or forceps delivery. If you are pregnant with twins or more, or if you are at risk for a multiple pregnancy, you should be aware of these and other potential problems you might experience. Preterm labor and birth pose the greatest risk to a multiple pregnancy.
Cesarean section is often needed for twin pregnancies and is expected for delivery of triplets. Since preterm labor and birth present such serious risks, the pregnant mother must understand the warning signs of early labor. Sometimes, preterm delivery can be delayed by a few days or more if it is detected early. Each day gained provides valuable fetal growth and development. Once a woman is in advanced labor, delivery cannot be stopped.
In rare instances, delivery of a second twin can be delayed. This delay, when possible, allows for continued growth in the protective environment of the uterus. Currently, there are no effective treatments to prevent preterm birth of multiples. The placenta is attached to the wall of the uterus, and the fetus is attached to the placenta by the umbilical cord. The placenta provides blood, oxygen, and nutrition to the fetus through the umbilical cord. Placental function is more likely to be abnormal in a multiple pregnancy.
If the placenta is unable to provide adequate oxygen or nutrients to the fetus, the fetus cannot grow properly. The placenta ages prematurely and may slow fetal growth, especially late in the third trimester. Another placental problem is twin-twin transfusion, a life-threatening condition in identical twins.
This transfusion occurs when blood flows from one fetus to the other through a connection in a shared placenta. Therapeutic amniocentesis and laser coagulation of blood vessels that link circulation to the twins in the placenta s may reduce complications of twin-twin transfusion. Preeclampsia, also known as toxemia, occurs 2 to 5 times more often in multiple pregnancies.
The condition may progress and threaten the health of the mother and baby. When severe, the mother may have seizures, and stroke or other life-threatening complications are possible.
Contact your medical team immediately if you have any signs of preterm labour. It may be possible to slow down or stop the labour. A caesarean section is usually the safest option when you are carrying 3 or more babies. This is because of the position of the babies, the position of the placenta or placentas , the risk that a placenta or umbilical cord can be compressed during a vaginal birth, and the risk that the babies can become entangled during a vaginal birth.
If you are carrying triplets or more, you will usually be offered a planned caesarean. You will be given a course of corticosteroids first. If you go into labour spontaneously, you will likely be given a caesarean after you arrive at hospital.
There will be a full medical team in the room, including a specialist obstetrician and paediatrician who are experienced in the care of triplets or more. Babies born before 34 weeks may need help with breathing, feeding and keeping warm. They are at greater risk of complications than babies born at full term. The neonatal intensive care unit has specialist medical staff and equipment to care for premature and sick newborn babies.
When your babies no longer need this high level of care, they may be transferred to the special care nursery or special care baby unit. Learn more here about the development and quality assurance of healthdirect content.
Learning you're pregnant with triplets or more can be a shock, but overall, most parents find having multiple babies to be a positive experience. Multiple pregnancies, including triplets and more, are rare but require lots of support.
Find out about the different types of multiple pregnancy here. Feeding multiple babies, such as triplets or more, can be challenging at first, but even breastfeeding is possible with some expert help.
It can produce boys, girls, or a combination of both. Fraternal multiples are simply siblings conceived at the same time.
But just as siblings often look alike, fraternal multiples may look very similar. Fraternal multiples each have a separate placenta and amniotic sac. Click Image to Enlarge. Sometimes, 1 egg is fertilized and then splits into 2 or more embryos. This is called identical twinning. It makes all boys, or all girls. Identical multiples are genetically the same.
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