Also, more women are waiting until later in life to attempt pregnancy, and older women are more likely than younger women to get pregnant with multiples, especially with fertility treatment. Although major medical advances have improved the outcomes of multiple births, multiple births still are associated with significant medical risks and complications for the mother and children. If you are at risk for a multiple pregnancy, this booklet will help you learn how and why multiple pregnancies occur and the unique issues associated with carrying and delivering a multiple pregnancy.
You may know someone who has twins, but do you know how twins occur and how they develop? There are two types of twins: identical and fraternal non-identical. Identical twins occur when a single embryo, created by the union of a sperm and an egg, divides into two embryos.
Each embryo is monozygotic, genetically identical, and both will be the same sex. 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. It seems that the splitting of a fertilised egg happens at random. But hyper ovulation where the ovaries release more than one egg each month is certainly influenced by genetics, so women who come from families where non-identical multiples are common do have more chances of having their own multiple births.
Statistics vary but some research suggests conceiving triplets naturally occurs 1 in every births. Via fertility assistance, the likelihood increases to around 1 in every Their data shows that the chance of having identical triplets is 1 in 62, pregnancies. Multiple pregnancies are considered high-risk pregnancies.
Carrying triplets is a lot of work for your body, hello back aches, pelvic pain, increased swelling and more. There is also an increased chance of pregnancy complications, such as high blood pressure preeclampsia and diabetes.
The bubs are also at higher risk of being smaller than expected and premature and may need to go to neonatal intensive care for a period after birth.
Staying calm about coronavirus: 6 ways to cultivate calm in your family. Join Now Log in. Parents Recommend. Already a member? Most triplets are born between weeks of gestation and caesarean section delivery is common.
Smaller hospitals tend to refer mothers who are pregnant with triplets to larger, metropolitan or tertiary maternity hospitals. This is because of the availability of specialist staff and resources for both obstetric and premature baby care. Shock, denial, terror and anxiety are the most common responses.
Most parents find out they are expecting triplets when an ultrasound is done and three tiny embryos are seen on the screen. Multiples may be suspected beforehand due to exaggerated pregnancy symptoms, the use of fertility drugs or assistance, or alternately, a family history of multiple births. But suspecting triplets and having this confirmed are very different realities.
Many couples emerge from the ultrasound office feeling numb and in shock. Others may laugh hysterically and feel over the moon. Sometimes, the follicles overreact to higher FSH levels and two or more eggs are released and fertilized, resulting in a multiple pregnancy.
A family history of identical twins does not necessarily make you more likely to have multiples, although the offspring of male identical twins may be more likely to have their own identical twins.
However, if you have fraternal twins non-identical in your family, your chances of conceiving twins rise. If there are fraternal twins on both parents' or egg or sperm donor's sides, your odds for twins go up even higher. A history of fraternal twins on the maternal side of the family indicates a higher likelihood of ovulating more than one egg per cycle.
Extra body fat leads to increased levels of estrogen, and higher levels of estrogen can lead to overstimulation of the ovaries. Instead of releasing just one egg at ovulation , the ovaries may release two or more.
While the odds of twins may increase, other factors associated with being overweight can make it more difficult to conceive. People who are taller than average are more likely to have twins. One study found that people averaging Why this happens isn't clear, but one theory is that better nutrition which may lead to more height is partially behind the increased rate of twins.
People who conceive while breastfeeding are more likely to conceive twins than people who are not. It's true that breastfeeding can also suppress fertility and prevent pregnancy, specifically during a baby's first six months if the baby is exclusively breastfed.
However, it is possible to get pregnant when breastfeeding—and with twins! One study found the rate of twins to be While research is still ongoing, some studies have found that people who eat a lot of dairy products are more likely to conceive twins. One theory is that the growth hormones given to cows affect the hormone levels in humans. Twins are more common in people who have carried many pregnancies and have large families. Meanwhile, Black people also are more likely to conceive twins than White people, while Asian people are the least likely to conceive twins.
Fertility treatments that boost ovulation can lead to twins, triplets, or higher-order multiples. Conceiving multiples is a potential risk of fertility treatments and one that can possibly be reduced with careful monitoring and targeted treatment such as single embryo transfer with IVF treatment or using the lowest possible effective dosage when treating with gonadotropins.
You may wonder why conceiving multiples is considered a "risk" and not a potential benefit to fertility treatments. After all, if you've been struggling to get pregnant, wouldn't a double or triple blessing be a good thing? The fact is that multiple pregnancies come with added risks to the parent and babies.
Not all treatments for infertility increase your odds of conceiving twins, but most do. Here are some of the treatments that may lead to twins. Gonadotropins, whether used with or without IUI treatment, have the highest rate of twins and higher-order multiples.
Contrary to popular belief, IVF treatment is not the main source of triplet and higher-order pregnancies. IVF twins are relatively common, with the twin rate highest for people younger than 35 at The IVF twin rate is lower for people over age 35 at 9. According to CDC birth statistics , there were , infants born in twin deliveries in the United States in That's There were 3, triplet births and just quadruplet and higher-order births during the same year.
These numbers include naturally occurring multiples, along with those conceived with fertility treatment. The rate of multiple births increased and peaked during the s but has been declining over the past decade. In the general population, identical twin pregnancies occur 0.
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