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How fast should your baby regain their birth weight?

Even when breastfeeding is going well, many moms wonder whether their newborn is getting enough milk and gaining weight at a healthy rate. Here are some clues.

How fast should your baby regain their birth weight?

Photo: iStockphoto

My daughter was just under a week old when something changed: Her sweet disposition gave way to fussiness, she was suddenly agitated while nursing and she became difficult to console. I’d heard about cluster feeding, but it seemed like my baby was always latched onto one of my breasts, and she was crying more than ever.

Our paediatrician quickly assessed that my milk still hadn’t come in yet and my baby was very, very hungry. While colostrum is all a baby needs in the first few days, this “liquid gold” usually transitions to breastmilk between day three and day five. He handed us some ready-made formula to supplement with, gave me the name of a lactation consultant and told us to return the next day. I left feeling both comforted and like a complete failure—my baby had dropped too much weight, and all those hours spent nursing had yielded almost nothing.

With the help of a great lactation consultant and a very supportive paediatrician, my daughter was soon feeding and growing like a champ. We didn’t have to supplement at all after three weeks, and I was able to breastfeed exclusively for almost a year. Our struggle was brief and ended happily, but here’s what I wish I’d known sooner.

How much weight will my newborn lose?

Your newborn could lose five to 10 percent of their body weight in the first two or three days, according to medical experts.

“It’s very common for babies to lose weight in the first couple of days,” explains Abigail Corbin, a registered midwife and partner at Hawthorne Midwives in Milton, Ont. This weight loss is totally normal and to be expected.

“Part of this weight loss might be related to fluids,” says Elyanne Ratcliffe, a paediatrician and medical lead of the Feeding and Swallowing Team Clinic at McMaster Children’s Hospital in Hamilton. Babies are often born with a “puffy” look before shedding some water weight early on, which helps explains that quick drop. These guidelines are the same regardless of your baby’s birth weight or how you’re feeding them (breast, formula or a combination of both).

“We get concerned when the baby loses 10 percent or more and isn’t gaining back the weight they lost,” adds Corbin.

When should my newborn regain their birth weight?


It’s usually around two weeks, say experts, though there is some wiggle room.

“Babies should regain their birth weight by three weeks of age, but it’s very uncommon to take that long,” explains Corbin. “Most babies are back to their birth weight by two weeks. At three weeks, we would consult with a paediatrician to see what else might be going on.”

Ratcliffe agrees that a two-week period is standard to regain their weight, give or take. “Babies are supposed to gain an ounce a day, but we like to say that they get one ‘day off’ a week—this is just an easy way to remember it,” she says. “They should be gaining an average of 20 to 30 grams a day in the first few weeks of life.”

Looking ahead, Ratcliffe says that your baby should be tripling their birth weight and doubling their length during their first year of life. Your healthcare providers will monitor this weight gain in the early days and weeks of your baby’s life, either through well-baby appointments at your doctor’s office or during home visits by your midwife. This follow-up care is often reassuring for new parents, who might have concerns about their child’s feedings and growth.

Like many new moms, Lindsay DeGroot had concerns about her son, Miles, who was born weighing seven pounds, 13 ounces. “When we brought him home, he was very tired and wanted to sleep all day,” she says. “He would wake up long enough to latch on and then, after a minute, fall asleep.”


DeGroot tried several ways to keep Miles awake during feedings—undressing him and placing a cool, damp washcloth on his skin—but they were ineffective. “I felt like I was torturing the poor kid!” she adds.

After struggling for two days, DeGroot was in tears, convinced that her newborn wasn’t getting enough to eat. How could he be eating enough, she wondered, when he would nurse for such a short time before nodding off? DeGroot called her midwife, who came for a house visit. Turns out, Miles was well hydrated and in great health. He had lost less than 10 percent of his body weight, so he wasn’t in the danger zone. “By day seven, he was back to his full birth weight,” she says. “That reassured me that he was getting adequate nutrition.”

How do you know if your newborn is getting enough to eat?

“Typically, until a baby gets back to their birth weight, they shouldn’t go more than three hours between feedings—this means from the start of one feeding until the beginning of the next,” explains Anita Arora, a lactation consultant at The World of My Baby in Milton, Ont. “We want to see at least eight feedings in a 24-hour period.” She emphasizes that breastfed babies will nurse frequently and encourages new moms not to limit time at the breast. “Watch the baby, not the clock!” she advises.

If your newborn is underweight, Arora suggests waking them every three hours to feed, including throughout the night. Once the baby is back to their birth weight, they should be strong enough to give cues when it’s time to eat and you can switch to what’s known as “feeding on demand.”

There are several ways to evaluate how effectively an infant is feeding. “You can’t measure how much you’re feeding at the breast, but you can look for satiation cues,” explains Arora. “They’re ‘milk drunk’: They’ve fallen asleep, there’s proper diaper output, you’ve seen and heard swallowing, and the baby seems to be full.”


If you’re formula feeding or exclusively pumping, one of the biggest challenges is knowing how much to offer. A standard bottle can hold six to eight ounces of liquid, which is two to three times what a newborn requires per feeding—they only need a couple of ounces at a time. Parents often don’t realize this and fill up the bottle or feel like the baby should be finishing it off. Arora teaches paced bottle feeding, which gives baby time to cue when they’ve had enough.

“Formula bottles are huge—no newborn baby needs that much,” says Arora. “A newborn’s tummy is the size of a cherry.” (For a handy reference chart, check out The Best Start Chart, a popular midwifery resource on optimal feedings and diaper outputs in the first three weeks of life.)

Overfeeding doesn’t happen as often with a breastfed baby because milk is released slowly and they will stop when they feel full, whereas a bottle-fed baby can chug an entire bottle down before the “I’m full” signal hits their brain.

When should you ask for help?

Ratcliffe notes that a lot of the stress around feeding and newborn weight gain stems from parental expectations and unhelpful comments made by other family members rather than medical issues. “Sometimes the baby is fine, but Aunt Sue made the parents worry,” she explains. That said, you should never ignore your instincts, and remember that your healthcare providers are there to reassure you or address any concerns. Reach out to your doctor or midwife if your newborn is struggling to feed or agitated while feeding, not meeting the recommended diaper outputs, losing weight or inconsolable.

A few simple tweaks to your feeding plan or even a shift in expectations is often all it takes. Before you know it, that tiny baby will be bursting out of their newborn sleepers and you’ll be packing them away tearfully—or triumphantly.

This article was originally published on Apr 08, 2019

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