Twins. The very word can make some people overjoyed and hopeful, and sends a shiver of fright down the spines of others. And that’s fair enough, the thought of parenthood is daunting enough for some, and then thinking about if you doubled that soon to be joy...for many, it’s terrifying. But scores are fascinated by the mystery that is twins.
How does it happen...what differences can there be...what are some of the risks? All of these questions are asked by people on a regular basis, and have been explored even in the media, in movies. (Danny DeVito and Arnold Schwarzenegger in the movie Twins, anyone?)
Do twins interest you? Well, we may have some interesting facts that’ll intrigue you.
15 The Study of Twins
Did you know, there’s actually a word for studying Twins? It’s called gemellology, and it’s literally the scientific study of twins and twinning. The word twin probably derived from an ancient German word, twine, which literally means ‘two together’. People have been interested in studying twins since ancient times, dating back to Romulus and Remus, Castor and Pollux, Jacob and Esau, and Fafner and Fasold.
Twins are mysterious to many people, especially twins that come from the same egg. The word ‘gemellology’ derives from the Latin word geminare, which means ‘to double’, or the Latin word gemellus, which means ‘twin-born’. (Some sources say the former, others say the latter.) This study is where the information from this whole article basically comes from, and for that, I say “Thank you!” to gemellology!
14 Foreign Language
If you’re a mother of twins, you’ll know all about what I’m talking about right now. Have you ever heard twins speak in what sounds like gibberish to you, but they know exactly what they’re talking about? You’re not losing it, this is called cryptophasia, or idioglossia. It’s an autonomous language that’s created and shared between twins.
According to research, around 40% of twins invent their own languages. Researchers believe that the really close siblings sometimes use each other as models for learning vocabulary and applying meaning to sounds, even if the sounds are complete nonsense. Sometimes their special language disappears as they begin school, but not always. The more time siblings spend together, the higher the chance that they will end up making up their own language to communicate. Oh, and this isn’t limited to verbal children. Nonverbal and Deaf children have been known to do this too.
13 Conception vs Birth
Some scientists believe that the number of twins conceived greatly outnumbers the amount of actual twin births. Some say that up to 1 in 8 pregnancies begin as twins, but only 70 births end up as twins. One author has said that 80% of twin pregnancies results in some kind of loss, and other sources say that number is closer to 30%. But of the 133 million people born worldwide in 2000, an estimated 7 million should have been twins.
If you’re on a fertility drug, it may raise your chances of conceiving twins. After fertility treatments such as IVF or ICSI, you’re about 20 times more likely to have a multiple pregnancy than someone who conceived naturally. Why? Because despite regulations, IVF often involves introducing two or more embryos into a woman’s uterus, and fertility drugs like Clomid stimulate the ovaries, increasing the odds of you releasing more than one egg at once.
12 Work, Work, Work, Work, Work!
So, imagine the workload that you have when you have one baby to care for. It’s a lot of hard work, especially as they get bigger. Now, double that and add in a few extra tasks that you have to do. This is the workload of a mom to multiples. Imagine you’re changing your kids’ diapers. They’ve both pooped at the same time. You bring them to the bed to change them, and begin to work on the first one. As you get the first diaper undone, your baby rolls and begins crawling off. No big deal. You lay them back down and start over. Repeat this process over and over and over until you’ve done it about 6 times and baby is finally changed. Repeat this process with the second kiddo, unless you walk to put that one in the playpen until you finish baby 2.
A 1983 study actually showed that a mother of 6 month old triplets expends an average of 197.5 hours a week out of a possible 168 hours between herself and paid/volunteer assistance on the care of her children and home. This didn’t even include time for mom to bathe, dress, sleep, eat, or relax!
11 Mirror Image Twins
These twins account for about 25% of identical births. Their hair parts and falls in opposite directions, they have mirror image fingerprints, and if one is a righty, the other is a lefty. The theory is that, if these twins face each other, they look like exact reflections of each other. They are always the same sex and blood type. A few cases of identical twins exist who are of the opposite sex, but this is very rare and very unlikely.
These twins are monozygotic, meaning they form from one fertilized egg. If the split occurs late, more than a week after conception, the twins have a higher chance of developing reverse asymmetrical features. Fertilized eggs that split after 12 days of conception would be more likely to develop into conjoined twins. Mirror Image isn’t a term for a type of twin, just their physical features. The majority of twins are not the rare mirror image, with fraternal twins being the most common.
10 Siamese Twins
We just got done discussing Mirror Image twins, and in there, we mentioned conjoined twins, which is where the egg splits 12 days or more after conception. This is an extremely rare phenomenon, ranging an estimated 1 in 49,000 to 1 in 189,000 births. Approximately half of all conjoined twins are stillborn, and an additional one-third die within 24 hours after birth. Most of the live births are female, while most of the stillbirths are male.
There are almost a dozen types of conjoined twins. One of the most common classifications is known as thoracopagus twins, which are connected at the upper portion of the torso. Thoracopagus twins share a heart, which makes it nearly impossible to separate them and save them both. These twins make up about 40% of all conjoined cases.
There are other kinds as well, such as the omphalopagus type, which is where the twins are joined from the breastbone to the waist, and the craniopagus twins, which are joined at the head and are the rarest form of conjoined twins.
9 Premature Birth
With twins, there’s less room for growth, and with that comes the risk of premature birth. According to the March of Dimes, close to 60% of all twins and more than 90% of triplets are born prematurely, which is any time before 37 weeks. The average twin pregnancy lasts until 35 weeks. Triplet pregnancies often last until around 33 weeks, and quad pregnancies last even less, with them ending at 29 weeks, so as the number of babies goes up, the time frame the pregnancy will last drops even less.
With premature birth, there are risks. Babies born before their time may not be fully ready for the outside world. Their lungs, brains, and other organs may not be completely developed, and their immune systems may not be ready to fight off bacteria. They also may not be able to suck or swallow. The earlier the birth, the greater the risks, and the higher the mortality rate. Babies born between 34 and 37 weeks generally do fine, but babies born before 28 weeks, while they may survive, they will need intensive medical care and a lot of luck.
8 More Chance of a Twin Pregnancy
There are a lot of factors that can naturally make you more likely to have a twin pregnancy. One of them is age. Researchers have found that women over the age of 35 produce more follicle stimulating hormone than younger women, which is what makes your eggs release when mature. More of this hormone makes more eggs drop. And this chance goes up even more for women over the age of 35. You also up your chances when you have twins in your family. Heredity doubles your chances of having twins, but only on the maternal side. Even if the paternal side is loaded with twinsanity, the chance won’t increase to conceive twins.
Other factors include having had twins before, and even having been pregnant before! With every pregnancy, the odds that you’ll have twins goes up a little, but that may have something to do with the whole age thing. Another factor is weight. Overweight women are significantly more likely to have twins.
Up to 22% of twins are left handed! This is compared to the percentage of the non-twin population, which is only around 10%. No one is entirely sure why this is, and why the percentages go up for the twin population. Hand preference comes down to a variety of factors, some genetic, and some environmental. There’s a few interesting theories about what makes people left handed, though.
Some speculate it’s genetic. It’s never been proven and a right handed gene has never been located, but some believe that left handed people simply lack this gene. Some say it’s prenatal trauma or hormonal imbalances that attribute to left handedness. There’s also the vanishing twin theory, which stated that left handed people were originally part of a pair, one half of an identical duo, but the right-handed sibling doesn’t develop very early on and is reabsorbed into the mother’s body.
6 Vanishing Twin Syndrome
This syndrome was first recognized in 1945. This happens when a twin or multiple disappears in the uterus during pregnancy as a result of miscarriage. The fetal tissue is absorbed by the other sibling, the placenta, or the mother, which gives the appearance of a vanishing twin. Before we had ultrasound, the diagnosis of a vanishing twin was made through an exam of the placenta after the delivery of the child. Today, with early ultrasounds, we can see twins and multiples in the first trimester, and a follow up ultrasound may show the one twin not being there anymore.
The cause of vanishing twin syndrome is unknown, and abnormalities that result in the vanishing twin appear to be present early in development. Analysis of the placenta or fetal tissue often shows chromosomal abnormalities in the vanishing twin, while the surviving twin is usually healthy. Improper cord implantation can also be a reason for it.
5 Twin Gene?
Yes, having twins can be genetic. However, they won’t be identical. Fraternal twins, however, can run in families, and a woman who has a sibling that is a fraternal twin is 2 and a half times more likely to have twins than average. That said, only the mother’s genetics matter for this. The father can have twins all over the board and their genetics just won’t matter in the least in determining if twins is a chance.
Why? Well, it’s as simple as the kinds of twins. Identical twins happen from an egg splitting into two, which is a random event. Fraternal twins happen because a woman releases two eggs in one cycle, known as hyperovulation. Some women have genes that make them more likely to hyperovulate, and this means that the chance of two eggs being fertilized at once goes up.
4 Years Apart
There have been cases of twins being born 2 or more years apart from each other! However, it’s not the way you’re likely thinking. This happens thanks to the miracle that is IVF. Some parents have difficulties conceiving naturally, and so, they turn to doctors to help them make their dreams of children come true. Doctors use the mother’s eggs and the father’s sperm to make embryos, and sometimes this ends up with extra embryos. Well, all embryos from the same batch are considered to be ‘twins’ or multiples, because they’re of the same batch.
So, when one child with the batch of embryos is conceived and then they freeze the embryos and then, years later, implant another one from the same batch? You get twins, born years apart. It’s incredible, amazing, and I’m sure it’s difficult to explain to people who are wondering just how they have twins that are years apart!
3 Daddy Issues
If you thought the last one was strange, well this one is going to have you tilting your head. Twins can in fact have different fathers. Studies show that as many as 1 in 400 sets of fraternal twins are bipaternal. How? Well remember what hyper-ovulation does. Now, this is how bipaternal twins happen. Two eggs from the same mother get fertilized by two different fathers in the same ovulation period. And it doesn’t always happen in the same 24 hour window. If a woman is with two men in a period of about 3-4 days, and she’s released 2 eggs, and she happens to be ovulating, it can result in a pair of bouncing babies who are bipaternal.
That said, if you know twins who look nothing alike, don’t assume they have different fathers! Like any set of siblings, twins with the same dad can look nothing alike, and can even possibly look like different races.
2 Identical...or Not?
Identical twins are identical, right? That’s what makes them, well, identical...doesn’t it? Not always. In fact, that bit about identical twins being fully identical is a rarity. Until recently, any differences in identical twins has been attributed to environmental differences, but recent studies contradict that belief. There are differences down to the genetic level that show up and create little, hard to see differences, and sometimes differences in the genetic code that you just can’t see. For example, one twin may have a set of genes on a chromosome that indicate a risk for leukemia, while another does not.
This discovery gives hope for a very rare, but pressing issue in the case of criminal suspects who have identical twins. If one twin is a suspect, and the location of the other twin can’t be determined, then the jury is left without the ability to find guilt beyond a reasonable doubt in cases that rely on DNA evidence. If there are genetic differences that can be discovered, then that could help sort things out.
1 A Twin-tastic Diet?
There’s a few things you can do to make it more likely to have twins. First off, people low on nutrition are less likely to have twins, so make sure you take your vitamins, especially your folic acid. Also, be well nourished. Surprisingly, underweight people are less likely to have twins. Being well nourished and even overweight to a degree can increase chances of twinning. Being better nourished means putting on weight in a healthy manner, though. Make sure to talk to your doctor about any plans to gain weight.
Some foods are thought to up your chances, also. Dairy and yams, in particular, are possibly linked to a better chance of having twins. Studies show that consuming dairy really may increase your chance of twinning. An African tribe who have a diet rich in wily yams has a twin birth rate 4 times higher than the global average, but many doctors are skeptical about if it contributes to twinning at all.
Whoa. From the freaky to the medical mystery, there’s a lot we don’t know completely about when it comes to twins. A lot of it is still a mystery even to the most skilled doctors! But we learn more every single day, and in ten years, who knows, maybe we’ll be able to figure out just how to conceive twins and more about what makes them tick!
Do you have twins? Do you want twins? Let us know in the comments!