Dreaming of double the newborn cuteness, but thinking it’s out of the realm of possibility? In reality, the idea of having twins may not be so far-fetched. (Just remember, it’s also double the diaper changes.)
But before you stock up on matching outfits and choose coordinating names, it’s important to understand how twins are conceived and the added factors involved.
There are some circumstances — whether naturally occurring or gained through fertility treatments — that may make you more likely to have twins.
(Already expecting twins? Here’s what you need to know.)
It’s estimated that 1 in 250 pregnancies results in twins naturally, and there are two ways to conceive them.
The first involves a single egg being fertilized by a single sperm. Reproduction 101, right? But then, somewhere along the way, the fertilized egg divides into two, resulting in identical twins.
The chances of having identical twins is relatively rare — around 3 or 4 in every 1,000 births. And while it may be obvious, identical twins are always the same sex, either both boys or both girls, at birth. Why? Well, they don’t just look alike — they also share the exact same DNA.
Fraternal twins, on the other hand, result when two separate eggs are fertilized by two separate sperm cells. Both fertilized eggs implant into the uterus and — 9 months later — two babies are born.
Fraternal twins can either be two boys, two girls, or a boy and girl. They may or may not look a lot alike. That’s because, unlike identical twins, they don’t share the exact same DNA. In fact, aside from age, they’re no more similar than brothers and sisters born years apart.
You may have heard that twins “run in families.” This is partially true. Your chances of having fraternal twins may be higher if you’re a fraternal twin yourself or if fraternal twins run in your family.
One reason for this may be hyperovulation, which is a situation where the body releases two or more eggs during ovulation — basically a requirement for having fraternal twins.
And hyperovulation can be passed down in your DNA — from your mom’s genes or, interestingly, your dad’s. (It can also happen once in a while in women who don’t regularly release more than one egg or have twins in their family, though.)
Are you over age 35? If you’re looking to have twins, you may hit the jackpot if you’re also in your upper 30s or in your 40s.
Women of “advanced maternal age” (we’re sorry to use the phrase, but it’s commonly used in medical settings to mean over age 35) have a higher chance of conceiving twins, says the Mayo Clinic.
Hormonal changes that happen as you near menopause may encourage the body release more than one egg during ovulation. If two or more are fertilized and both implant, you might just need two cribs in your nursery.
Taller women seem to have a higher rate of having twins. This may sound a bit strange, but researchers credit a certain insulin-like growth factor with this possibility.
Women who have overweight or obesity also have a higher chance of conceiving twins naturally. Specifically, the chances are highest if your body mass index (BMI) is above 30, according to a
A later study in 2016 that analyzed maternal characteristics among women in Norway said rates of twins increased among women with BMI above 25.
A word of warning here: Don’t intentionally gain weight to increase your chances of having twins. Having a BMI over 30 may also place you in the high-risk category of pregnancy, so talk to your doctor about a healthy weight for you before getting pregnant.
This may occur because women who eat dairy may be taking in extra insulin growth factor. The cows release this hormone into their milk and — when consumed — it may influence human reproduction.
Note that this is just one analysis of the medical records of who’d given birth. And little research (if any) regarding dairy intake affecting twin birth rate has been completed since.
While increasing your intake of this root vegetable certainly is not a surefire way to conceive multiples, eating yams — chock-full of fiber, vitamins, and minerals — certainly can’t hurt you!
Do you already have a child who’s looking to be a big brother or sister? He or she may be the reason you end up having twins. That’s right! A previous pregnancy — or, better yet, previous multiple pregnancies — may increase your chances of having twins.
In fact, according to the , women between the ages of 35 to 40 with four or more children are three times more likely to have twins than a woman under 20 without children.
The why isn’t entirely clear, but it may simply be because with each pregnancy, you’re a bit older.
If you’re familiar with artificial reproductive technology (ART), in vitro fertilization (IVF), and other fertility treatments — like intrauterine insemination (IUI) — you may already know that twins are a heightened possibility.
While the procedure of IUI itself doesn’t increase your chances of having twins, certain drugs associated with it might. Clomiphene citrate (Clomid) and letrozole (Femara) are ovulation-stimulating medications.
Both of these drugs are often given in IUI cycles and may help the body produce multiple eggs that may release at the same time. If two (or more) are fertilized and implant, twins are a possibility.
In one 2014 study, the rate of twins with Clomid was 7.4 percent. Femara had a lower rate of just 3.4 percent. Those numbers may not seem high, but they’re still quite a bit higher than the chance of conceiving twins naturally.
And there’s more. Gonadotropins, like follicle stimulating hormone (FSH), stimulate the growth of egg follicles. These injectable medications are also often used in IUI and other fertility treatments, and the rate of twins while using these medications is a whopping 30 percent.
Drugs are also a part of IVF. But one of the main factors that increases your chances of twins with this reproductive technology is the number of embryos you decide to transfer.
Some couples choose to transfer just one. While the single embryo might split and turn into identical twins, this isn’t too likely.
The more likely scenario is with regard to fraternal twins. If you transfer two (or more) embryos and they both successfully implant and develop, twins (or more!) are on the way.
And consider this: Some couples may choose to transfer two embryos during IVF. Say one of those embryos splits and then all three implant in the uterus. The result would be triplets — two identical twins and one fraternal sibling.
First things first: Before you start pinning cute twin nurseries on your Pinterest board, understand that twin pregnancies aren’t always fun and (baby shower) games.
Being pregnant with multiples may carry certain complications and will automatically land you with a “high risk” classification with your doctor or midwife. Women carrying twins are at an increased risk of developing preeclampsia and gestational diabetes.
That’s not to say you can’t have a totally healthy pregnancy with two babies. It just means you may need to be monitored a bit more closely.
Beyond the risks, a lot of the factors that increase the odds of having twins aren’t exactly in your control.
So while you can choose to eat more dairy and yams, you can’t exactly change your height, race, or family history of multiple births. Purposefully gaining weight before pregnancy isn’t necessarily a good idea either.
And if you’re banking on having kids late in life to increase your odds of having twins, understand that with age comes reduced fertility and more chances of chromosomal abnormalities.
If you’re still stuck on the idea of two, reproductive technology may give you the most control. But experts currently recommend younger women transfer just
Ovulation-enhancing drugs used alone or with IUI require a prescription and may carry some serious risks, like higher chance of ovarian hyperstimulation or ectopic pregnancy.
Drugs and procedures like IVF are also costly and typically reserved for couples who have been diagnosed with infertility. For women under 35, infertility means not getting pregnant with timed intercourse in the course of a year. And for women over 35, this timeframe shortens to 6 months.
We’re not trying to be a Debbie Downer here. Talk to your doctor — particularly your reproductive endocrinologist if you’re doing fertility treatments — about twins.
They can tell you about any associated risks unique to you and if doing a multiple-embryo transfer with IVF might be an option.
Unfortunately, there’s no special pill you can take that will guarantee you’ll be rolling a double stroller around your neighborhood like a boss. (But we think you’re a boss regardless.)
This isn’t to say you can’t have a little fun trying to increase your odds by dining on more cheese and roasted yams or crossing your fingers about your next IUI.
There are certainly both risks and rewards with twins. But before you get too carried away with dreaming, try first looking forward to seeing double… with the lines on your pregnancy test. We’re sending baby dust!