With all the incredible advancements we have made as a species, knowing how to conceive twins is still somewhat elusive to us.
Sure, there are fertility treatments that increase the likelihood of multiple births, as well as a range of factors that may improve your chances—but a How-To guide for twins? Sadly, that’s not something we have.
So, spoiler alert: you haven’t landed on a recipe that will break down the steps of how to get pregnant with twins. Why? Because, like so much of mamahood, we just don’t have as much control over things as we would like.
That being said, if you’re dreaming of having two peas in your pod, various factors may increase the likelihood of that happening.
Table of Contents 📝
- How to have twins
- The chances of having twins
How to have twins
The first thing to know is that there are two main types of twins—monozygotic and dizygotic—and these two types are formed differently.
- Monozygotic twins, or identical twins, are formed from a single zygote. A zygote is a fertilized egg. In the case of monozygotic twins, the zygote splits into two. Each half goes on to form its very own fetus. The fact that they are of a single zygote means that they come from both the exact same egg and the exact same sperm that fertilized said egg. That means, monozygotic twins share the exact same DNA.
- Dizygotic twins, or fraternal twins, are formed from two separate eggs. Each one of these eggs is fertilized by a different sperm, resulting in two separate zygotes. Even though dizygotic twins spend a whole lot of time swimming in the same uterus together, they share the same amount of DNA as any other siblings would (50%).
(The topic of twin types gets a little more nuanced, but we’ll leave it here for now. You can learn more here.)
Which parent carries the gene for twins?
The short answer? The mama (sort of)—but it depends on what twin type you’re talking about.
When it comes to identical twins, we don’t really know of a genetic connection. That is, having identical twins does not appear to pass down from one generation to the next.
However: when it comes to fraternal twins, there is a genetic link. Mamas are 2.5 times more likely to have fraternal twins if they have a sibling who is a fraternal twin. The chances of having twins are higher because there’s a genetic link between increased levels of FSH (the follicle-stimulating hormone) in families that may promote hyperovulation (where both ovaries release an egg in the same cycle).
But, as always, it gets more complicated. While you may have an increased chance of conceiving twins if it runs in your family, genetics is not the only factor to consider.
The chances of having twins
What are my chances of getting pregnant with twins?
Twins occur in about 32.1 of every 1000 births. (Triplets ring in at 87.7 of every 100,000 births.)
What’s interesting is that after being on the rise for many years, twin births appear to be on the decline in the United States. While we don’t quite have definitive answers as to why this is the case, researchers have a pretty solid theory: we’re getting better at IVF treatments.
IVF and twin births are good friends. In 2013, multiple births occurred in a whopping 40% of all IVF pregnancies in the United States.
So why does IVF mean an increased chance of having twins? To improve the odds of a successful pregnancy, fertility specialists have followed the practice of transferring more than one embryo at a time. And, as you’d expect, the likelihood of more than one embryo getting fertilized is increased when there is more than one embryo around.
As medical advancements are made in this area, and IVF techniques become more sophisticated and lean towards maxizing the success of a single embryo transfer, the chances of having twins this way have declined.
Can you increase your chances of having twins?
While there is no 100% proof-backed plan, there are some factors that do increase the chances of having twins.
- IVF. While this may seem like a simple path to twindom, doctors will likely advise you against explicitly trying to conceive twins in this manner. Beyond it being very expensive, having twins through IVF can result in your babies being born preterm and/or having a low birth weight. Being pregnant with twins also comes with health risks for you, such as preeclampsia and gestational diabetes.
- Waiting! As it turns out, there are more reasons to wait to have children than just ensuring that you feel ready for mamahood. Age plays a role in whether or not you have twins because FSH (that follicle-stimulating hormone again) increases as you age. Mamas over 35 have the best shot at twins.
- Having some older siblings for your twins. As it turns out, the likelihood of having twins increases if you’re already a mama. If you have already conceived twins, it goes up even more—by as much as 4 times!
- Breastfeeding. If you are currently breastfeeding, your chances of having twins might be up to 9 times higher! (This is complicated because your chances of conceiving at all are lower when breastfeeding, particularly during the first 6 months of your baby’s life. But if you do conceive, it may be twins!)
- Diet. There is evidence to suggest that dairy intake can increase your chance of having twins by up to 5 times. This could be because of a protein called IGF that may up the sensitivity of the ovaries to that follicle-stimulating hormone. The follicles in which the egg grow in contain these IGF receptors on the surface. But downing the dairy isn’t a surefire way to twindom—it’s but one small element in a sea of biological and environmental factors.
So, mama. If it’s twins you want, we hope it’s twins you get—just know that there is no guaranteed solution that will get you there.