What are Irish twins?

You had a 3-month-old baby at home when – surprise! – you got a positive pregnancy test , and will be delivering Baby No. 2 just nine months later. You've got Irish twins! They’re in diapers at the same time, share all the same clothes, books, and toys, and generally go everywhere together as baby BFFs. They’re almost twins , but not quite.

Irish twins isn’t a medical term; it’s a colloquial one used to convey the joys, challenges, sleepless nights , and double diaper duties associated with having two kids so close in age.

One mom from our BabyCenter Community writes, “My second daughter was born a year ago, just one week before my first child’s first birthday. They are eleven months and three weeks apart exactly. It was really hard at the end of my pregnancy, but so worth it! Their bond is like none I’ve ever seen and they love each other so much.”

Here's what having kiddos super close in age is really like, the pros and cons, plus how you can make parenting Irish twins a little bit easier.

What are Irish twins?

The term "Irish twins" actually originated in the late 1800s. It was a term used to describe children born one right after another to Irish Catholic immigrants who followed Church teaching on the use of artificial birth control. And while there’s no official definition, experts agree that Irish twins are siblings born within 12 months of one another.

The benefits of having Irish twins

Is it hard to have kids within a year of one another? For sure! But there are some serious benefits, too.

You’ve already mastered “baby mode”

One of the advantages of having siblings one right after the other is that you probably already have a finely-tuned routine down pat, says Ilan Shapiro , M.D., a Los Angeles-based pediatrician. Your new baby can slide right into it without your having to make much of an adjustment.

“Usually when there is an age gap between siblings, parents tend to forget things and it can be hard to start taking care of an infant again,” he says.

It may cut down on some costs

While it might seem like having two kids close in age will be more expensive, it can actually help you save money in some regards. Dr. Shapiro says not only can your kids share many toys, books, and clothes either at the same time or as gently used hand-me-downs – you can also stretch your budget by buying lots of items in bulk (like diapers, baby wipes, and even toddler-friendly snacks ).

A BabyCenter Community mom noted this about her Irish twins, too, saying that she just left out all the toys and supplies she used for her older child since her younger child would be ready for those items as soon as the older one had outgrown them.

They'll have shared experiences – and a lifelong friend

When kids are close in age, they tend to share similar hobbies, experiences, and friend groups, which makes it easier for parents to navigate family schedules, says ob-gyn Sarah A. Hoopes , M.D., who's based in Houston.

Multiple moms in the BabyCenter Community describe how close and connected their Irish twins are, saying “I wouldn't have it any other way – it melts my heart consistently” and “They are so cute together and best friends already.” One mom of a 24 month-old and 12 month-old (with another baby on the way) writes that she expects having 3 kids under 3 will be hard , but she says “seeing my two daughters have the sweetest friendship has put me at ease.”

Another mom writes that having Irish twins was an “awesome adventure” that starts with being “constantly in survival mode trying to keep two babies alive” but ends in having siblings that turn into best pals and go through all their developmental milestones together.

When kids are close in age, they tend to share similar hobbies, experiences, and friend groups, which makes it easier for parents to navigate family schedules. - Sarah A. Hoopes, M.D.

The cons of having Irish twins

Many of the people who have Irish twins don’t plan on having two babies in one year. And while there is a lot of good that can come from having kiddos super close in age, there are some logistical and physical issues related to going through pregnancy , birth , and breastfeeding back-to-back.

Lack of sleep

If you thought you were tired with one baby, adding a second baby to the mix shortly afterward is a recipe for prolonged sleep deprivation: “The moment you have two infants or toddlers , the lack of sleep can take a toll on parents,” says Dr. Shapiro.

Not only will you have two young children struggling to sleep through the night (which is normal for their age), you might also have two kids teething at the same time, or two kids dropping the paci at the same time, too. It can take a toll after a while.

Jealousy between siblings

When you have two very young children (or multiple children in general!), you will always feel like your attention is being divided or like you need to be in two places at once. This is totally normal, but it can be tough on parents, says Dr. Hoopes, adding that it can cause additional fatigue and stress.

The effect on the older child in an Irish twin scenario is a concern commonly voiced in the BabyCenter Community, too, with moms wondering if it’s fair to their older child, if they’ll be able to breastfeed both kids, and how they will ever handle two babies at once. One new Irish twin mom even writes, “I have so much mom guilt; my one year-old is jealous and heartbroken [over the new baby]. When I walk away from her, put her down, or hold the newborn, she throws tantrums and I feel so bad.”

An increased risk of health complications for you

From a health perspective, getting pregnant less than 18 months after your previous birth can be more dangerous for some mothers, putting them at risk of preeclampsia , postpartum hemorrhage , and preterm birth , says Dr. Hoopes. Several studies have shown that back-to-back pregnancies are associated with more health complications because the body doesn’t have time to fully heal and reset in between. Your provider can help you understand how heavily you should weigh these factors, if you're planning for two close in age.

Many moms who find out they’re pregnant soon after giving birth also worry about how pregnancy will affect breastfeeding, since it can lower your milk supply, cause mild uterine contractions, and simply be logistically difficult to accomplish with a growing belly. (FYI, studies show that breastfeeding during pregnancy is safe, and while challenging, can totally be done.)

Tips for parents with Irish twins

Raising Irish twins is demanding and exhausting but ultimately rewarding, laying the foundation for a lifelong friendship between siblings (and a lot of “we’ll laugh about this later!” stories for parents). Here are a few expert tips to make your life a little bit easier when caring for two babies or young children:

• Shop smart . It's a great idea to buy necessities in bulk to save money, as well as to recycle or reuse toys, clothing, and other everyday items to cut down on the costs, says Dr. Shapiro. This can really help you save when you're raising two infants or toddlers at the same time. For example, if one of your children has outgrown their diaper size, but the younger one is almost there, save any extras to use as soon as the next child is ready for them.

• Find a routine that works – and stick to it . Figuring out sleep routines and feeding patterns for two young children can be difficult, so it’s important to create a routine that functions like a well-oiled machine to take care of both kids, says Dr. Shapiro. “When you create a routine that works, it can bring relief to and have a huge impact on the entire family,” he says. "Combining their wind down routines at night, like bath, bed, and reading can be very beneficial," says Chandani DeZure, M.D. , pediatrician and BabyCenter Medical Advisor. You can also try to get them napping at the same time, but once your toddler drops a nap, you may need to stagger them (which could actually allow for more 1:1 time with each baby), she adds. And depending on your baby's ages, you may be able to sync up their eating schedules, too. "If you're nursing both babies, you can stagger their feedings," she says, "and if you are only feeding one, you can meal prep for the older baby so that they can eat something while you're feeding your baby."

• Foster independence . BabyCenter moms to Irish twins emphasize the importance of gently fostering independence with your older child while expecting your next baby, making sure they still feel loved but that they are also confident enough to handle small challenges. This might include encouraging your older child to sleep in their own bed, or to spend time playing independently in a playpen or baby proofed area. You could also consider weaning them, if necessary (so you can focus only on breastfeeding your newborn).

• Make room for individuality . It's important, as your kids get older, to allow each of them to find their own personality. You can do this by giving them the time and space to do something uniquely interesting to them, says Dr. Hoopes. For example, one of your little ones may love the playground and the other may love a trip to the grocery store. Try to lean into their interests and make time for each activity. Otherwise, they may end up feeling resentful or jealous of one another, or angry with you for always prioritizing their sibling.

• Ask for help when you need it . All parents need a break from time to time, and this is especially true when two little kids are in the mix. “Never be afraid to ask for help or advice,” says one BabyCenter Community mom of Irish twins. “It may feel like you should be able to cope all on your own, but what is best for your kids is the most important thing – and that includes not pushing yourself too hard and harming your own health.”