Research shows that pregnant women who consistently take prenatal supplements—especially iron, magnesium, calcium, and folic acid—have significantly better pregnancy outcomes. According to Gram Research analysis of a 199-woman cohort study, women taking iron and omega-3 supplements reduced their risk of gestational hypertension by up to 91%, while those taking calcium were 48% less likely to need cesarean delivery. Overall adherence to prenatal supplements was 63.8%, with the most commonly used supplements being folic acid (82.9%) and iron (71.9%).
A new study of 199 pregnant women in Jordan found that taking the right vitamins and supplements during pregnancy is connected to better health outcomes for both mothers and babies. Researchers tracked which supplements women took, how consistently they used them, and what happened during pregnancy and birth. Women who took iron and magnesium had fewer cases of high blood pressure during pregnancy, while those taking calcium were less likely to need cesarean sections. The findings suggest that prenatal supplements aren’t just recommended—they may actually make a real difference in preventing pregnancy complications.
Key Statistics
A 2026 prospective cohort study of 199 pregnant women in Jordan found that folic acid was the most commonly used prenatal supplement at 82.9%, followed by iron at 71.9%, with overall supplement adherence reaching 63.8% throughout pregnancy.
According to research reviewed by Gram, women taking iron and omega-3 supplements during pregnancy reduced their odds of gestational hypertension by 87% and 91% respectively in a 199-woman cohort study conducted from 2023-2025.
A 2026 cohort study of 199 pregnant women found that calcium supplementation was associated with a 48% reduction in cesarean delivery rates, though it was also linked to increased urinary tract infections.
Research from a 199-woman prospective cohort study showed that supplement adherence fluctuated across pregnancy trimesters, with only 63.8% of women maintaining consistent prenatal vitamin and supplement use throughout their pregnancy.
The Quick Take
- What they studied: Whether pregnant women who take vitamins and supplements have better pregnancy outcomes and healthier babies compared to those who don’t take them consistently
- Who participated: 199 pregnant women in Jordan, enrolled starting in their second trimester and followed through delivery. The women were recruited from a government hospital between February 2023 and March 2025.
- Key finding: According to Gram Research analysis, women who took iron and magnesium supplements had significantly lower rates of gestational hypertension (high blood pressure during pregnancy), and those taking calcium were less likely to need cesarean sections. Overall, 63.8% of women stuck with their supplement routine throughout pregnancy.
- What it means for you: If you’re pregnant or planning to become pregnant, taking prenatal supplements as prescribed—especially folic acid, iron, calcium, and magnesium—appears to reduce the risk of serious pregnancy complications. However, this study shows associations, not definitive proof of cause-and-effect, so discuss supplement use with your healthcare provider.
The Research Details
Researchers conducted a prospective cohort study, which means they followed the same group of pregnant women over time from their second trimester through delivery. This approach is stronger than simply asking women to remember what they took, because researchers collected information regularly at monthly prenatal visits and reviewed medical records. The study included 199 pregnant women recruited from a government hospital in Mafraq, Jordan, between February 2023 and March 2025.
At the start of the study and throughout pregnancy, researchers asked women detailed questions about which supplements they were taking, how often they took them, and whether they stuck with their routine. They also collected information about the women’s health, medical history, and any pregnancy complications. After delivery, they reviewed birth records to see what happened with the baby’s health and weight.
This design is valuable because it captures real-world supplement use patterns and allows researchers to see which supplements were most commonly used and which were associated with better outcomes. The monthly check-ins mean the data is more reliable than if women had to remember everything at the end of pregnancy.
Following women throughout their pregnancy rather than asking them to recall information later makes the results more trustworthy. By checking in monthly and reviewing medical records, researchers could see exactly which supplements women took and when, and then connect that information to actual health outcomes. This approach helps identify patterns that might be missed in other types of studies.
This study has several strengths: it followed women over time, collected information regularly rather than relying on memory, and reviewed actual medical records. However, the study was conducted in one hospital in Jordan, so results may not apply equally to all populations. The researchers used convenience sampling (enrolling women who were available rather than randomly selecting them), which could introduce bias. Most importantly, the study shows associations between supplements and outcomes but cannot prove that the supplements caused the better outcomes—other factors could be involved. The researchers themselves note that further studies are needed to confirm these findings.
What the Results Show
The most commonly used supplements were folic acid (taken by 82.9% of women) and iron (taken by 71.9%). Overall, about 64% of women consistently took their supplements throughout pregnancy, though this varied by trimester. When researchers looked at pregnancy complications, they found several important patterns: women who took iron and magnesium supplements had significantly lower rates of gestational hypertension (high blood pressure during pregnancy), with odds reduced by 87% for iron and 91% for omega-3 supplements. Women taking calcium were 48% less likely to need a cesarean section.
The study also found that women taking calcium had higher rates of urinary tract infections, though the reason for this association isn’t clear and may be due to other factors. Low birth weight was associated with not taking multivitamins, and gestational hypertension was linked to not taking magnesium, iron, folic acid, or omega-3 supplements. These findings suggest that specific supplements may protect against particular pregnancy complications.
Beyond the main findings, the research revealed patterns in how women used supplements across pregnancy. Adherence rates fluctuated throughout the three trimesters, suggesting that women may have difficulty maintaining consistent supplement use as pregnancy progresses. The study also identified that certain combinations of supplement non-use were associated with worse outcomes, indicating that multiple nutrients working together may be important for maternal health.
This research aligns with existing medical knowledge that prenatal nutrition is crucial for pregnancy health. Previous studies have shown that folic acid prevents birth defects, iron prevents anemia, and calcium supports bone health. This study adds new information by showing real-world patterns of supplement use in a Middle Eastern population and by identifying specific associations between individual supplements and pregnancy complications like gestational hypertension and cesarean delivery rates. The findings support current prenatal care guidelines that recommend these supplements.
This study has important limitations to understand. First, it was conducted in one hospital in Jordan with 199 women, so the results may not apply to all pregnant women worldwide or in different healthcare settings. Second, the study shows associations (supplements were used when certain outcomes occurred) but cannot prove that the supplements caused those outcomes—other factors like diet, exercise, or genetics could explain the results. Third, the researchers used convenience sampling rather than randomly selecting participants, which could mean the women studied were different from the general population. Finally, the study relied on women’s reports of supplement use, which might not be completely accurate. The researchers acknowledge these limitations and call for larger, more rigorous studies to confirm their findings.
The Bottom Line
Based on this research, prenatal care providers should emphasize the importance of taking prescribed prenatal supplements consistently throughout pregnancy, particularly folic acid, iron, calcium, and magnesium. Women should discuss their supplement routine at each prenatal visit and report any difficulties with adherence. However, these findings are suggestive rather than definitive—they show associations but not proven cause-and-effect relationships. Always follow your healthcare provider’s specific recommendations for your individual situation.
This research is most relevant to pregnant women and those planning pregnancy, as well as healthcare providers who counsel pregnant women about prenatal care. Women in their second and third trimesters should pay particular attention to maintaining consistent supplement use. The findings may be most applicable to women in similar healthcare settings to the study location, though the basic principles of prenatal nutrition apply broadly. Women with specific health conditions should discuss supplement use with their providers, as individual needs may vary.
The benefits of prenatal supplements appear to develop over the course of pregnancy. Since this study followed women from the second trimester through delivery, the protective effects of supplements like iron and magnesium against gestational hypertension likely develop gradually with consistent use over weeks and months. Starting supplements early in pregnancy and maintaining consistent use throughout appears most beneficial. You shouldn’t expect immediate results, but rather a gradual reduction in pregnancy complications over the course of several months of consistent supplement use.
Frequently Asked Questions
What prenatal supplements should I take during pregnancy?
Research shows folic acid, iron, calcium, and magnesium are the most important prenatal supplements. This study found 82.9% of women took folic acid and 71.9% took iron. Always consult your healthcare provider about which supplements are right for your individual needs and health history.
Can prenatal vitamins prevent pregnancy complications?
This study found associations between specific supplements and fewer complications: iron and omega-3 reduced gestational hypertension risk by up to 91%, and calcium reduced cesarean delivery odds by 48%. However, the study shows correlation, not definitive proof of prevention. Discuss with your provider.
How important is it to take prenatal supplements every day?
Very important. This study found that only 63.8% of women maintained consistent supplement use, and adherence fluctuated across trimesters. Women who didn’t take supplements consistently had higher rates of complications like gestational hypertension and low birth weight.
What happens if I miss doses of my prenatal vitamins?
Missing doses reduces the protective benefits of prenatal supplements. This study showed that women with inconsistent supplement use had higher rates of pregnancy complications. If you struggle with adherence, discuss strategies with your healthcare provider, such as using a pill organizer or setting daily reminders.
Are prenatal supplements safe during pregnancy?
Prenatal supplements recommended by your healthcare provider are considered safe and important for pregnancy health. This study of 199 women found that appropriate supplement use was associated with better outcomes. Always discuss any supplements with your provider before starting them.
Want to Apply This Research?
- Track daily prenatal supplement intake by logging each vitamin or supplement taken (folic acid, iron, calcium, magnesium, omega-3, etc.) with a yes/no check-mark. Aim for 100% adherence and monitor monthly adherence rates to identify patterns of missed doses.
- Set a daily alarm for the same time each morning to take prenatal supplements with breakfast. Use a pill organizer labeled by day of the week to make it easier to see which supplements you’ve taken and which you’ve missed.
- Review supplement adherence monthly during prenatal visits. Track any pregnancy symptoms like high blood pressure, urinary tract infections, or unusual swelling alongside supplement use patterns to identify correlations. Share this data with your healthcare provider to adjust your supplement routine if needed.
This article summarizes research findings and should not replace professional medical advice. Prenatal supplement recommendations vary based on individual health status, dietary intake, and medical history. Always consult with your healthcare provider or obstetrician before starting, stopping, or changing any supplements during pregnancy. This study shows associations between supplement use and outcomes but does not establish definitive cause-and-effect relationships. Individual results may vary based on genetics, overall health, diet, and other factors not measured in this study.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.