At first, I thought this was regular, run-of-the-mill morning sickness. But after a few days, it became clear my symptoms started each time I had one of my three-a-day gummies. Did my prenatal vitamins and nausea go hand-in-hand? I switched vitamin brands to find out. Then I switched again. And again. Some seemed a little better, some a little worse, but I was unwell after taking every single one.
Physically, I felt horrible, and even more troubling, I wasn’t able to play with my two-year-old. I was barely eating and could hardly get out of bed most days. I kept reminding myself of all the good my vitamins were doing for baby #2: lowering the risk of neural tube defects, supporting the development of the placenta, helping to develop my little one’s lungs, and so on. Even so, I was struggling every day. I didn’t know how much longer I could keep taking the vitamins.
I started asking my mom-friends for advice and found that, unfortunately, many pregnant people have similar side effects to prenatal vitamins. (Even singer Halsey said she had to stop taking her vitamins while pregnant because “the vomiting got really bad.”)
“It’s not uncommon to have patients not tolerate or have, particularly, gastrointestinal distress in early pregnancy associated with their prenatal vitamin intake,” says Anne Waldrop, MD, a maternal-fetal medicine fellow at Stanford University Hospital. She adds that this is “unfortunate” because vitamins are “evidence-based to help keep those patients: moms and their fetuses, healthy.”
But not all prenatals will cause the same reactions. Meleen Chuang, MD, an OB-GYN at NYU Langone Health, explains, “Depending on the type of extra supplementation, certain types of prenatal vitamins may cause more gastrointestinal side effects than other types of prenatal, particularly if there is extra iron, calcium or other minerals,” she says.
I wanted to learn more about negative reactions to prenatal vitamins, what parents should know about their prenatal nutrition, and what can be done to help.
Switch up how you take your iron supplements
Iron is an important nutrient during pregnancy: not only is it used to make hemoglobin, which carries oxygen to the growing fetus, but it also helps the baby’s brain development. So, it’s particularly unfortunate that this supplement is said to make morning sickness symptoms worse.
“Having an iron-rich prenatal vitamin can certainly be a likely culprit for gastrointestinal issues,” Dr. Waldrop says. “Some patients have nausea, constipation, diarrhea, or nausea and vomiting concurrently.”
Still, there’s hope. If a pregnant person is having gastrointestinal trouble, Dr. Waldrop suggests choosing an iron-free prenatal and then adding a second iron-only vitamin to the mix. Separating the iron from the rest of the nutrients could provide some relief, as Dr. Waldrop notes that iron supplements don’t need to be taken daily. Studies have shown that this nutrient can actually be absorbed better when taken every other day. So, if iron continues to cause stomach issues—at least the parent-to-be only needs to deal with side effects for half the week.
Meanwhile, Lizzy Swick, a registered dietitian based in Montclair, New Jersey, says that taking two different pills may not be necessary. She points out that some people will experience a negative reaction to a particular type of iron, not iron itself. “Some women will better tolerate a form of iron called iron bisglycinate, known commercially as Ferrochel,” she says.
So, sometimes simply switching to a new prenatal brand, with different ingredients, will do the trick. Some experts saying having some ginger can also help.
Don’t be alarmed by higher levels of nutrients in prenatal vitamins
More than a month into my prenatal vitamin troubles, I stood in my kitchen, inspecting the nutrition labels of all five brands of prenatal vitamins I’d tried in the past few weeks. To my surprise, each nutrition panel was completely unique.
Not only did the ingredients vary, but the percentages for each item were different from brand to brand. One contained about 150 percent of each vitamin’s daily recommended value. Others had 200 percent or 300 percent on nearly every line. This, I was certain, was my problem: I’d been taking supplements that contained way too many nutrients for my sensitive stomach, and now, my body was rebelling.
Luckily, experts say that higher percentages in prenatal vitamins aren’t generally something to worry about.
Swick explains that while large doses of certain vitamins can indeed be dangerous, elevated levels of the nutrients found in prenatal vitamins shouldn’t cause any serious harm to a pregnant person or their baby. She explains that some companies incorporate higher levels of nutrients simply as a way to lower costs. “If the form of the vitamin isn’t the active, bio-available form, chosen to save money by the company, they’ll include higher amounts should there be a conversion problem,” she says.
Dr. Chuang notes that vitamin takers will simply urinate out the excess, water-soluble, nutrients. “This is why your urine smells different when taking prenatal vitamins,” she says.
Choose high-quality prenatal vitamins
Like other dietary supplements in the United States, over-the-counter prenatal vitamins do not require U.S. Food and Drug Administration (FDA) approval. A lack of third-party testing can be unsettling for any avid vitamin-taker, but for someone growing a tiny person, this fact can be downright stressful.
So, before choosing a supplement, Dr. Waldrop suggests asking an OB-GYN for advice. If the parent-to-be is already taking a supplement, she recommends bringing the bottle to the doctor. “Let them review that you’re getting the daily doses recommended by the United States Preventive Services Task Force,” she says.
Further, Swick warns that some vitamins contain unwanted ingredients. “Supplements often contain unnecessary filler and additives to help keep costs down during the manufacturing process,” she explains. Still, finding a safe, effective prenatal vitamin isn’t too difficult. She suggests looking for vitamins that are NSF or GMP certified.
Of course, pregnant people may want to do a little research on their own as well. When choosing a vitamin, Swick lists questions to help find the best brands: “Does the product contain the actual form or amount of nutrients it says it does? Are there heavy metals or do the heavy metals exceed the acceptable limits? Is the company willing to share any analysis on heavy metals or pesticide use?”
“The ideal company is transparent and has nothing to hide,” she adds.
Remember that each pregnancy is different
While I’ve learned that there are plenty of reasons why prenatal vitamins could make someone ill. I was frustrated with and even confused about my symptoms. After all, I hadn’t had any negative reaction to vitamins when I was pregnant with my first. So, what changed?
Dr. Waldrop simply says that different symptoms are to be expected in different pregnancies. “The reality is, every pregnancy is unique and there can also be drastic differences between a first, second, and third pregnancy.”
Plus, Swick points out that many people report their second pregnancy being harder than the first because they’re entering subsequent pregnancies in a nutrient-depleted state. “It’s harder to focus on your nutrition and self-care when you’re chasing after a toddler, sleep-deprived, overworked, or financially challenged,” she says.
I tried these expert-backed tips and eventually felt better
When it came to my own vitamin journey, I was happy to take these experts’ advice: I tried taking an iron supplement separate from an iron-free prenatal. I tried taking my gummies with bigger meals, and I asked my OB-GYN for brand recommendations. While some of it helped, I still felt a little nauseous every day after taking a vitamin. I started to wonder if I was simply going to feel crummy for nine months.
Then, one day, around my 14th week of pregnancy, I woke up, took a vitamin, and felt fine. The symptoms were gone. Days after, I started craving (and taking) the fruity flavor of the gummy vitamins I’d started out with: the same ones that had me curled up in bed, wanting to skip vitamins altogether just a couple of months before.
I wasn’t sure what happened. Maybe I’d finally figured out the right combination of food, timing, and brand. Or maybe, in the second trimester, my body adjusted to my higher hormones and my stomach wasn’t responding so drastically. Either way, I was glad I could finally take my vitamins comfortably.
Now, in my third trimester, I’m glad I didn’t give up on my prenatal vitamins. So far, my pregnancy has been healthy and I hope my determination to keep taking my vitamins has played some part in that. “Nutrition is quite humbling in how powerful a lever it is for human health,” Swick says. “Yet, it’s also only one component of many that shape the outcomes of our health and our children’s health.”