Your Likelihood Of Having Twins Or More

How common are twins and other multiple pregnancies?
Increasingly common, largely because more and more women are taking fertility drugs or turning to assisted reproductive technology (ART) to help them conceive. These treatments greatly increase a woman's chance of having twins or higher-order multiples. The famous McCaughey septuplets are one extreme example of the potential consequences of fertility treatments.

These days, about one in 32 births are twin births. This rate has gone up 65 percent since 1980, and it's more than double the rate among women who conceive without medical assistance — one in 89.

The rise in triplets and quadruplets is even more dramatic. Between 1980 and 1998, the rate of triplets and higher-order multiple births shot up by more than 400 percent, but it's crept back down over the past few years as fertility treatments have become more refined. In 2003, one in 535 births resulted in triplets, quadruplets, or more.

Meanwhile, the likelihood of having identical twins (when one fertilized egg divides in half) is about one in 250. This rate hasn't changed over the decades and is remarkably constant all over the world.

How likely am I to have more than one baby if I'm undergoing fertility treatment?
Fertility drugs stimulate your ovaries, increasing the odds that you'll release several eggs at the same time. On average, 20 percent of women taking gonadotropins will become pregnant with more than one baby. Women who get pregnant while taking the drug Clomid have a 5 to 12 percent chance of twins.

If you undergo in vitro fertilization (IVF), your chances of having more than one child are 20 to 40 percent, depending on how many embryos are placed in your womb. Other fertility techniques such as GIFT (gamete intrafallopian transfer) and ZIFT (zygote intrafallopian transfer) are also more likely to result in multiple pregnancies.

On its own, IUI (intrauterine insemination), in which sperm are injected into the uterus with a syringe, is the only fertility treatment that doesn't increase the chances of conceiving multiples. But most women who undergo IUI also take a fertility drug.

Fertility drugs and other treatments primarily increase your chance of having fraternal twins, where two eggs are fertilized by two different sperm. But there is now some evidence that women who undergo certain treatments also have somewhat higher rates of identical twins.

What other factors affect the chances that I'll have more than one baby?
While identical twins generally happen by sheer chance, there are several factors that influence your chances of having fraternal twins:

• Heredity: If you're a twin or if twins run in your family, you're slightly more likely to have a set yourself. Women who are fraternal twins have a one in 60 chance of bearing twins.

• Race: Twins are more common than average in African Americans and less common in Hispanics and Asians.

• Age: The older you are, the higher your chances of having fraternal twins or higher-order multiples. A 2006 study found that women over 35 produce more follicle stimulating hormone (FSH) than younger women. Ironically, increasing levels of this hormone are a sign of failing ovaries and declining fertility. But FSH is also the hormone that causes an egg to ripen in preparation for ovulation each month, and women with extra FSH may release more than one egg in a single cycle. So while older women are statistically less likely to get pregnant, if they do get pregnant, they're more likely to have twins.

• Number of pregnancies: The more pregnancies you've had, the greater your chances of having twins.

• History of twins: Once you have a set of fraternal twins, you're twice as likely to have another set in future pregnancies.

• Body type: Twins are more common in large and tall women than in small women.

source from http://www.babycenter.com

When And How To Find Out If You're Carrying Twins Or More

How and when will I learn whether I'm carrying twins or more?
Several decades ago, most women who were pregnant with multiples didn't find out until they were in labor. But such late-term surprises are rare today. Women typically discover they're having more than one baby during a routine ultrasound, often in the first trimester.

Your practitioner will likely recommend an ultrasound in your first trimester if you're unusually large for your gestation date. The most likely explanation is that you or your practitioner miscalculated your conception date. The ultrasound will help determine how far along you really are and whether your size is due to your carrying more than one baby.

If you're pregnant as a result of a fertility treatment such as Clomid, gonadotropins, or in vitro fertilization (IVF), you'll probably have an ultrasound within the first eight weeks to count the number of embryos that have implanted. Ultrasound is almost foolproof at revealing multiple pregnancies, particularly after six to eight weeks. However, the more babies you're carrying, the easier it is for one to get overlooked.

How do twins end up fraternal or identical?
Fraternal twins develop from two eggs that are released and fertilized at the same time. They're known as dizygotic (DZ). Identical twins develop from one egg that splits into two and are thus known as monozygotic (MZ).

By the way, since they come from the same egg, monozygotic twins do share the same DNA, but these so-called "identical" twins are never truly the same. Although they have the same genetic makeup, they may have distinguishing characteristics that allow their parents to tell them apart. This may be due to environmental influences, either inside or outside the womb. Also, certain genes may end up being expressed differently in each twin.

How and when can I find out whether my babies are DZ or MZ?
Prenatal tests such as chorionic villus sampling (CVS) and amniocentesis can tell you for sure — at least in theory. These tests can be tricky to perform in multiples, and you may not be able to get a sample of each baby's DNA.

If you can't or don't want to have these tests, an ultrasound can often tell you whether your babies are dizygotic or monozygotic, based on whether there are one or two placentas and whether the babies are the same gender.

An experienced technician performing a trans-vaginal ultrasound between 9 and 14 weeks can determine with nearly 100 percent certainty whether your babies share a single placenta. (The accuracy rate drops to about 90 percent in the second trimester as the womb becomes more crowded.)

If your babies share a placenta, they're monozygotic. If there are two placentas, your twins may be DZ or MZ. All dyzygotic twins and 20 to 30 percent of monozygotic twins have separate placentas.

By 18 to 20 weeks, a technician may be able to identify the babies' genders, assuming that both babies are positioned so that the technician can get a good look at their genitals. If an ultrasound clearly shows that you have a boy and a girl, you'll know that your babies are dizygotic. Monozygotic twins are nearly always the same sex.

If the ultrasound shows two placentas and only one gender — or if the results are unclear — you may have to wait until your babies are born for your answer. After the birth, your practitioner will determine whether the twins shared a placenta. Because separate placentas sometimes fuse together and appear as one, a laboratory test may be needed to tell how many there were.

If placental analysis doesn't solve the mystery, you can order an at-home DNA test for a little over $100, but you'll have to wait one or two weeks for the results. As mentioned above, monozygotic twins will have almost always have identical DNA, while dizygotic twins will share about 50 percent of their DNA.

As your babies grow up, it'll probably be easy to tell what type of twins they are just by looking at them. If they look so much alike that other people can't tell them apart, they're almost certainly monozygotic. Any obvious difference in their hair color, eye color, or facial features means that they're dizygotic.

Why is it important to know whether twins are dizygotic or monozygotic?
Finding out whether twins are DZ or MZ isn't simply a matter of satisfying idle curiosity. It can also be important to know for medical reasons.

For one thing, monozygotic twins who share a single placenta face a special health risk during pregnancy. Up to 15 percent of these twins will develop twin-to-twin transfusion syndrome (TTTS), a dangerous condition in which one twin "donates" fluids to the other. The twin on the receiving end tends to grow more rapidly than the donor twin.

Without treatment, the condition is usually fatal for both babies. If your twins are sharing a placenta, your caregiver will monitor their weight gain and watch for other signs of TTTS. If your caregiver suspects TTTS, prompt treatment may prevent complications and keep your babies healthy.

Even after your babies have grown up, it could be important to know whether they're dizygotic or monozygotic. For example, if one twin is found to have a genetic disease, an MZ sibling will have it, too. A DZ sibling, on the other hand, might be spared.

There's one more reason to find out whether your twins are fraternal or identical: Everyone will ask — from friends and relatives to strangers on the street. People are fascinated by twins, so be prepared to answer the question over and over again throughout your pregnancy and for years to come.

source from http://www.babycenter.com

Having Male Twin Sibling Reduces A Woman's Fertility

WASHINGTON (Reuters) - Women who have a male twin are less likely to marry and have children, perhaps because of being exposed to their brother's testosterone for nine months in the womb, researchers reported on Monday.

A study of Finnish twins showed that women were 25 percent less likely to have children if their twin was a male. Those who did have children gave birth to an average of two fewer babies than women who had a twin sister.

Based on an analysis of 18th and 19th century data, researchers found women who had a male twin also were 15 percent less likely to get married, Virpi Lummaa of the University of Sheffield in Britain and Finland's University of Turku and colleagues reported.

"We show that daughters born with a male co-twin have reduced lifetime reproductive success compared to those born with a female co-twin," they wrote in their report, published in the Proceedings of the National Academy of Sciences. "This reduction arises because such daughters have decreased probabilities of marrying as well as reduced fecundity."

Researchers have long known that fetuses are influenced by hormones in the womb. Because male and female fetuses have similar levels of the "female" hormone estrogen, girl twins are more likely to be affected by testosterone in the womb.

Studies of rodents show that hormones in the womb affect a baby's development, but researchers have lacked studies of actual populations to see if what is in theory possible biologically in fact happens in real life.

Lummaa's team used Finnish church records that dated from 1734 to 1888, looking at the births and marriages affecting 754 twins.

"The study used data from humans living in a pre-industrial era so as to obtain results that are not affected by advanced health care and contraception," Lummaa said in a statement.

"Our results show that females who had a male cotwin have reduced fitness compared to those who had a female cotwin, but the success of males is unaffected by the sex of their cotwin," the researcher wrote.

Perhaps the female twins had more masculine attitudes and behaviors that affected their decision to get married, the researchers speculated. Male features could have made the women less attractive to mates, they added.

Other studies have shown, for instance, that exposure to testosterone in the womb affects facial features and even finger lengths.

Also, exposure to elevated levels of testosterone during development can promote diseases that compromise fertility, such as reproductive cancers, the said.

By Maggie Fox

source from http://www.babycenter.com

Second-born Twin Has Higher Post-delivery Risk

Second-born twins are twice as likely as the firstborn to die at birth or shortly after due to complications during delivery, British researchers report.

The risk — which remains very small — appears to be lessened when both twins are delivered by caesarean section, the study found.

"Compared with the first twin, the second twin is more than twice as likely to die during delivery or in the first four weeks of life," said lead author Dr. Gordon Smith, the head of the department of obstetrics and gynecology at Cambridge University. "This is observed among twins born at term — 36 weeks or later — but not in prematurely delivered twins," he added.

The absolute risk to the second twin is still very small, about one in every 250 twin births, Smith said.

His team published its findings in the March 2 online edition of the British Medical Journal.

In the study, Smith's group collected data on twin pregnancies in England, Northern Ireland, and Wales between 1994 and 2003. The researchers detected 1,377 cases of twin pregnancies where one twin died during delivery or shortly after.

The deaths were due to direct complications of birth, Smith said. These included prolapsed umbilical cord (delivery of the baby's umbilical cord occurs prior to the baby's birth), complications of breech birth, and separation of the second twin's placenta after delivery of the first twin.

"We found that the risk for the second twin tended to be less among those delivered by caesarean section," Smith said. "This is consistent with previous studies, which had also suggested that planned caesarean section was associated with lower risks of death and morbidity for the second twin," he said.

However, there is no information that shows directly that caesarean section is protective, and the risk to any one twin baby remains very small, Smith said.

"Among twins born prematurely, the high risk of death due to prematurity probably masks the small additional risk of death due to complications of delivery for the second twin," the researcher added.

Whether a woman chooses to have a caesarean delivery depends on the viewpoint of the individual woman, Smith said.

"This will involve her motivation to achieve a normal birth, her attitudes toward small risks of serious adverse events and her plans for future pregnancies. In particular, women planning many future births, and younger women, whose plans may be difficult to predict, may do better not to consider planned caesarean section due to the effects of this on future pregnancies," he said.

One expert believes that the risk of death of the second born twin is even smaller in the United States than in Britain.

"I would hate to see this study used as an excuse to have every mother with twins have a caesarean section," said Dr. F. Sessions Cole, the director of newborn medicine and head of the neonatal intensive care unit at St. Louis Children's Hospital.

Cole said that most twins delivered at full term are delivered vaginally. "Having all mothers with twins deliver by caesarean section would result in more risk to the mother than the small risks to the babies," he said.

Once the first twin is delivered, it is important to carefully monitor the second twin, Cole said. If there appears to be problems with the second twin, that baby may be delivered by caesarean section, he noted. "That's the standard of care today."

Cole believes that the data in the study applies only to Great Britain. "There would be fewer such deaths in the United States," he said. "There is much greater monitoring attention given to the second twin in the United States, given the malpractice risk that any obstetrician faces when he or she delivers twins," he said.


-- Steven Reinberg, HealthDay News

source from http://www.babycenter.com

Helping Twins Sleep At The Same Time

You've heard it a million times — twinsmean double the trouble and double the fun. (Parents of triplets and other multiples can change the numbers accordingly!) But it's hard to remember the fun part when you're struggling to get your crying twins to go to sleep and stay that way. We asked twins and multiples sleep experts Rebecca Moskwinski, M.D., of the National Organization of Mothers of Twins Club and Alexander Golbin, Ph.D., director of the Foundation for Children's Sleep Disorders, for their best strategies and tips. Here are their top suggestions:

Put your twins to sleep at the same time
Keeping your toddlers on the same sleep schedule is the key to developing a healthy sleep pattern and giving you some hope of time off. If your twins nap or go to bed at different times, one or both of them may be awake at any given time — leaving you feeling overwhelmed.

Establish a calming bedtime routine
A quiet, soothing bedtime routine such as a warm bath, a bedtime story, and a few minutes of cuddling, back rubbing, and quiet talk will help you prepare your twins for sleep. If you stick to a consistent bedtime routine, your toddlers will soon learn the signal that it's time to settle down.

Put your little ones to bed drowsy, but not asleep
Help them learn to fall asleep on their own by letting them drift off once they're in bed, rather than just before you put them down to sleep Moskwinski doesn't recommend rocking your twins to sleep, since they may come to depend on that cue to fall asleep. Moskwinski suggests using Richard Ferber’s gradual method to teach them to get to sleep by themselves.

Tend to your calm toddler first
If one is a screamer and the other is calmer, you may be tempted to tend to your wailing toddler first. Golbin strongly advises against this. The danger, he explains, is that your quiet one will miss out on the attention he needs. Before you focus on the screamer, make sure your quiet one is happy and settled. Don't worry about one twin waking up the other: Most twins and multiples don't seem bothered by their sibling's crying, even when they're in the same room.

Discourage nighttime waking
You can do this by keeping your twins as calm and quiet at night as possible. Keep their room dimly lit, and don't play or talk to them during the night more than necessary. You can encourage self-soothing by giving them a special soft toy or blanket to sleep with. These "transitional objects" are comforting and can help them go back to sleep.

Try separate rooms
Now that your twins are getting older, they're more likely to spend bedtime and naptimes talking and playing rather than getting their needed shut-eye. Some parents find that giving each twin his or her own room stops the nighttime antics and gives everyone some much-needed rest.

source from http://www.babycenter.com

What Is the Multiple Marker Test?

Between the 15th and 20th weeks of pregnancy, expectant mothers typically are offered a blood test called the multiple marker test. It can sometimes be called a triple screen or a quad screen, depending on the number of things measured.

For the screening, a sample of blood is drawn from the mother to measure the levels of hCG (human chorionic gonadotropin) and estriol, which are produced by the placenta, and alpha-fetoprotein (AFP), which is produced by the fetus. Sometimes the level of inhibin-A, which is made by the placenta, also is measured. The levels of these substances can help doctors identify a fetus at risk for certain birth defects, including neural tube defects (like spina bifida) and chromosomal abnormalities (likeDown syndrome).

In determining the results of the test, doctors take into account:

• the mother's age, weight, and ethnicity
• whether she has diabetes
• if she is having twins or other multiples
• the gestational age of the fetus

Many of these factors affect the levels of the substances being measured and the interpretation of the test results, so the accuracy of this information is vital. If any of the information is inaccurate, the results from the screening may be as well.

Receiving Abnormal Results

If you have undergone the multiple marker test and received abnormal results, there is no need to worry yet. Just because the test is abnormal doesn't mean that your child has a birth defect. Rather, an abnormal screen indicates that the fetus should be evaluated further.

Usually, when a pregnant woman's results show high levels of AFP, pointing to a possible risk of spina bifida or other neural tube defects, her doctor will order a detailed ultrasound to examine the fetus, including the fetal skull and spine. In addition, an ultrasound can confirm the age of the fetus and whether the woman is carrying multiples. The doctor also may offer amniocentesis, which is the withdrawal of amniotic fluid from the uterus for further testing.

If a woman's multiple marker screen results reveal low levels of AFP and estriol and high levels of hCG and inhibin-A, she has an increased risk of having a baby with Down syndrome. The next step is usually an ultrasound to confirm the baby's due date and to look for any obvious abnormalities. Unfortunately, ultrasound is not a very good test for detecting Down syndrome. For this reason, patients are offered amniocentesis so chromosome testing can be done on the fetal cells found in the amniotic fluid.

In general, remember that the multiple marker test is just a screen. It can identify many fetuses that are at risk for certain birth defects, but will not identify them all. A positive screen does not necessarily mean that there is a birth defect, but that there is a need for more evaluation.

If you have any questions or concerns about multiple marker testing, talk to your doctor or seek the advice of a genetic counselor.

source from http://kidshealth.org