Are artificial sweeteners safe during pregnancy?

Nobody knows for sure, because no randomized trial has tested artificial sweeteners in pregnant women. The European Food Safety Authority found no risk to the developing fetus from aspartame at its acceptable daily intake, except in women with phenylketonuria (PKU), and that assessment does not cover the other sweeteners. A 2021 meta-analysis of studies in 129,009 pregnant women linked daily use to an 18% higher risk of preterm delivery, on low to very low certainty evidence. The same analysis linked daily use to babies 24 g heavier at birth. Those are observational links, and the US Dietary Guidelines review of 2024 could draw no conclusion for pregnancy at all.

Unsettled. The answer is unsettled because the only evidence in pregnant women is observational. The randomized evidence on sweeteners comes from people who were not pregnant, and a link in a birth cohort can come from who chooses diet drinks as easily as from the drink.

What the trials found

No trial in pregnancy

We found no randomized trial that gave artificial sweeteners to pregnant women and measured how the pregnancy or the child turned out. The randomized trials that exist were run in other people. A 2019 systematic review with meta-analyses of 56 studies, 35 of them observational, found no differences for most health outcomes between people who used non-sugar sweeteners and people who did not, on very low to low certainty evidence, and pregnancy was not analyzed.

Swapping sugar for sweeteners does move body weight a little outside pregnancy. A 2014 meta-analysis of 15 randomized trials found body weight fell by 1.8 lb (0.80 kg) (95% CI 0.95 to 2.6 lb (0.43 to 1.17 kg) lower). A 2022 network meta-analysis of 17 trials in 1,733 adults with overweight or obesity found that replacing sugary drinks with low- or no-calorie sweetened drinks lowered weight by 2.3 lb (1.06 kg) (95% CI 0.9 to 3.8 lb (0.41 to 1.71 kg) lower) over a median of 12 weeks. Losing weight is not the aim of pregnancy, so these results do not carry over. In a Cochrane review of 9 trials in 979 people with diabetes, sweeteners left HbA1c unchanged against placebo, on very low certainty evidence. No pregnant women were among them.

Sweeteners are common in pregnancy. In the ROLO trial of 571 pregnant women in Ireland, one third ate or drank low-calorie sweeteners in every trimester. That trial measured intake and did not test whether sweeteners changed any outcome.

Preterm birth

The 2021 meta-analysis pooled three studies for preterm delivery and found a risk ratio of 1.18 (95% CI 1.09 to 1.28) with daily use. It also found babies 24 g heavier at birth (95% CI 1 to 46 g) and pregnancies 0.11 weeks shorter, all on low to very low certainty evidence. The abstract gives no absolute rates, so the 18% cannot be turned into a number of extra preterm births.

The largest single cohort is Danish. Of 59,334 pregnant women, those who drank at least one artificially sweetened soda a day had 38% higher odds of preterm delivery than those who drank none (odds ratio 1.38, 95% CI 1.15 to 1.65). A Norwegian cohort of 60,761 pregnant women found that more than one sugar-sweetened drink a day was linked to preterm delivery as well (odds ratio 1.25, 95% CI 1.08 to 1.45). A link that appears with sugar too points to something shared by people who drink a lot of soft drinks, which the sweetener alone may not explain.

Gestational diabetes

In a Chilean cohort of 1,472 pregnant women, 77.8% used non-nutritive sweeteners, and any use was linked to 58% higher odds of gestational diabetes (odds ratio 1.58, 95% CI 1.10 to 2.26). Intake came from a single 24-hour recall, and women who already see themselves at risk may be the ones who choose sweeteners.

The child's weight

In the Canadian CHILD cohort of 3,033 mothers and infants, daily artificially sweetened drinks in pregnancy were linked to twice the odds of overweight at 1 year (odds ratio 2.19, 95% CI 1.23 to 3.88). Only 5.1% of the mothers drank them daily, which makes that estimate unstable. Among 918 Danish mothers with gestational diabetes, daily drinks were linked to a higher risk of a large baby (risk ratio 1.57, 95% CI 1.05 to 2.35) and of overweight at age 7 (risk ratio 1.93, 95% CI 1.24 to 3.01).

In the US Project Viva cohort of 1,683 children, mothers in the highest quarter of intake averaged about one serving a day. Their children had a BMI z-score 0.20 higher in infancy and 0.21 higher in mid-childhood. In early adolescence the gap was 0.14 (95% CI minus 0.07 to 0.35), which no longer reached significance.

Sweeteners reach the baby

In 28 Danish women given a sweetened drink before a planned cesarean section, acesulfame, cyclamate, saccharin and sucralose all turned up in fetal blood, rising in step with the mother's levels. The coefficients ran from 0.44 for sucralose to 0.72 for cyclamate. That shows the fetus is exposed. It does not show harm, and the study was small and stopped earlier than planned.

For the rest of what is known about sweeteners, see the sweetener page.

Who should be careful

Not for everyone. Women with PKU should avoid or restrict aspartame, in pregnancy and outside it, according to the US Food and Drug Administration, because they cannot properly break down phenylalanine. The European assessment that found no fetal risk from aspartame names the same exception.

Women with gestational diabetes or diabetes before pregnancy are the group in which the cohort links to a heavier child were found, and the group most often steered toward sweeteners. The Cochrane review in diabetes is the nearest randomized evidence, and it did not include pregnant women. The cohort links to preterm birth and gestational diabetes above are the other cautions. All of them are observational, and none of them separates one sweetener from another.

What expert bodies say

The European Food Safety Authority, in its 2013 full risk assessment of aspartame, found no risk to the developing fetus from phenylalanine derived from aspartame at the acceptable daily intake of 40 mg per kg of body weight, with the exception of women with PKU. That assessment does not cover the other sweeteners. The US Food and Drug Administration advises people with PKU to avoid or restrict aspartame. The USDA review written for the US Dietary Guidelines in 2024 looked at low- and no-calorie sweetened drinks in pregnancy and after birth, and could draw no conclusion because evidence was lacking. The WHO 2023 guideline advises against using non-sugar sweeteners to control body weight, for everyone except people with pre-existing diabetes. That guideline is about weight, and it does not address safety in pregnancy.

How we searched

What would change this answer

• A randomized trial in pregnancy. One, the SweetPea trial, is registered and tests cutting non-nutritive sweeteners in pregnancy and breastfeeding.
• Cohorts that measure each sweetener separately. Diet drinks as a group mix aspartame, sucralose, acesulfame and others, and the sucralose-heavy Chilean data cannot speak for aspartame.
• A pooled analysis of pregnancy cohorts that reports absolute rates, so that an 18% relative link can be read as a number of extra preterm births.
• Cohorts that compare diet drinks with water, not only with no diet drinks, to separate the sweetener from the habit of drinking soft drinks.

Sources

1. ev-aswp-01 · Meta-analysis or systematic review · systematic review and meta-analyses of randomized and non-randomized controlled trials and observational studies · n = 56 studies (35 observational)
   Most health outcomes did not seem to have differences between the NSS exposed and unexposed groups.
   
   Who: generally healthy or overweight/obese adults and children; NSS within the acceptable daily intake for at least 7 days
   Effect: most outcomes no difference; adults BMI MD -0.6 (-1.19 to -0.01; 2 studies, n=174), very low to low certainty
   Certainty: Not about pregnant women; the widest synthesis as of 2019, evidence mostly weak.
   BMJ, 2019 · checked 2026-10-07 · we read the abstract
2. ev-aswp-02 · Meta-analysis or systematic review · meta-analysis of RCTs and prospective cohort studies · n = 15 RCTs, 9 cohorts
   In RCTs, LCSs modestly but significantly reduced all outcomes examined, including body weight (-0.80 kg; 95% CI: -1.17, -0.43), body mass index [BMI (in kg/m²): -0.24; 95% CI: -0.41, -0.07], fat mass (-1.10 kg; 95% CI: -1.77, -0.44), and waist circumference (-0.83 cm; 95% CI: -1.29, -0.37).
   
   Who: 15 RCTs and 9 prospective cohorts of low-calorie sweeteners from foods, beverages or tabletop use; not pregnant women
   Effect: RCTs body weight -1.8 lb (95% CI -2.6 to -0.95; metric: -0.80 kg, -1.17 to -0.43); BMI -0.24 (-0.41 to -0.07); cohorts no association with weight
   Certainty: Outside pregnancy; in pregnancy weight gain is not a goal, so it does not transfer directly.
   Am J Clin Nutr, 2014 · checked 2026-10-07 · we read the abstract
3. ev-aswp-03 · Meta-analysis or systematic review · systematic review and network meta-analysis of RCTs · n = 1733
   This substitution was associated with reduced body weight (MD, −1.06 kg; 95% CI, −1.71 to –0.41 kg) and lower BMI (MD, −0.32; 95% CI, −0.58 to –0.07), percentage of body fat (MD, −0.60%; 95% CI, −1.03% to –0.18%), and IHCL (standardized MD [SMD], −0.42; 95% CI, −0.70 to –0.14).
   
   Who: adults with overweight or obesity at risk for or with diabetes; median follow-up 12 weeks; not pregnant
   Effect: LNCSB for SSB: body weight MD -2.3 lb (95% CI -3.8 to -0.9; metric: -1.06 kg, -1.71 to -0.41); BMI -0.32; body fat -0.60%; moderate certainty for body weight
   Certainty: Outside pregnancy; aspartame in 7 of 11 comparisons with a named sweetener.
   JAMA Network Open, 2022, Association of Low- and No-Calorie Sweetened Beverages as a Replacement for Sugar-Sweetened Beverages With Body Weight and Cardiometabolic Risk · checked 2026-10-07 · we read the fulltext
4. ev-aswp-04 · Meta-analysis or systematic review · Cochrane systematic review and meta-analysis of RCTs · n = 979
   The MD for HbA1c was 0%, 95% CI -0.1 to 0.1; P = 0.99; 4 trials; 360 participants; very low-certainty evidence.
   
   Who: people with type 1 or type 2 diabetes; trials of 4 to 10 months; pregnant women not studied
   Effect: NNS vs placebo HbA1c MD 0% (95% CI -0.1 to 0.1; 4 trials, 360 participants); very low certainty
   Certainty: Closest to women with diabetes in pregnancy, but there were no pregnant women among the participants.
   Cochrane Database Syst Rev, 2020 · checked 2026-10-07 · we read the abstract
5. ev-aswp-05 · Observational data · systematic review and meta-analysis, mostly cohort studies · n = 129009
   'Low' to 'very low' certainty evidence revealed that daily consumption of AS was associated with an increased risk of preterm delivery (three studies, n 129 009; risk ratio = 1·18, 95 % CI 1·09, 1·28, I2 = 9 %), a 24 g increase in birth weight (three studies, n 64 417; mean difference (MD): 23·74 g, 95 % CI 0·89, 45·58, I2 = 0 %) and a 0·11 week decrease in gestational age (three studies, n 64 417; MD: -0·11 weeks, 95 % CI -0·19, -0·03, I2 = 0 %).
   
   Who: pregnant women; 10 cohort studies and 1 RCT; preterm analysis 3 studies
   Effect: preterm delivery RR 1.18 (95% CI 1.09 to 1.28); birth weight +23.74 g; gestational age -0.11 weeks
   Certainty: Pooling of observational data remains level C; confounding with sugary drinks and maternal weight is not excluded.
   Public Health Nutrition, 2021, Effects of prenatal artificial sweeteners consumption on birth outcomes: a systematic review and meta-analysis · checked 2026-10-07 · we read the abstract
6. ev-aswp-06 · Observational data · prospective cohort study · n = 59334
   In comparison with women with no intake of artificially sweetened carbonated soft drinks, the adjusted odds ratio for women who consumed ge 1 serving of artificially sweetened carbonated soft drinks/d was 1.38 (95% CI: 1.15, 1.65).
   
   Who: pregnant women, Danish National Birth Cohort 1996-2002; intake assessed in midpregnancy
   Effect: OR 1.38 (95% CI 1.15 to 1.65) for at least 1 serving/day; OR 1.78 (1.19 to 2.66) for at least 4 servings/day
   Certainty: A single cohort; the Norwegian MoBa reproduced only a weak association (see -07).
   Am J Clin Nutr, 2010 · checked 2026-10-07 · we read the abstract
7. ev-aswp-07 · Observational data · prospective cohort study · n = 60761
   Drinking >1 serving of SS beverages per day was also associated with an increased risk of preterm delivery (adjusted OR: 1.25; 95% CI: 1.08, 1.45).
   
   Who: pregnant women, Norwegian Mother and Child Cohort Study
   Effect: more than 1 serving/day of sugar-sweetened drinks: OR 1.25 (1.08 to 1.45)
   Certainty: The association for sugar-sweetened drinks as well points to a shared lifestyle factor, not the sweetener itself.
   Am J Clin Nutr, 2012 · checked 2026-10-07 · we read the abstract
8. ev-aswp-08 · Observational data · prospective birth cohort · n = 3033
   Compared with no consumption, daily consumption of artificially sweetened beverages was associated with a 0.20-unit increase in infant BMI z score (adjusted 95% CI, 0.02-0.38) and a 2-fold higher risk of infant overweight at 1 year of age (adjusted odds ratio, 2.19; 95% CI, 1.23-3.88).
   
   Who: healthy pregnant women and their infants, Canadian CHILD Study 2009-2012; 5.1% drank daily
   Effect: infant BMI z score +0.20 (95% CI 0.02 to 0.38); overweight at 1 year adjusted OR 2.19 (1.23 to 3.88)
   Certainty: Only 5% drank daily, so the estimate is unstable; level C.
   JAMA Pediatr, 2016 · checked 2026-10-07 · we read the abstract
9. ev-aswp-09 · Observational data · prospective cohort study · n = 918
   Compared to never consumption, daily ASB intake during pregnancy was positively associated with offspring large-for-gestational age [adjusted relative risk (aRR) 1.57; 95% CI: 1.05, 2.35 at birth], BMIZ (adjusted β 0.59; 95% CI: 0.23, 0.96) and overweight/obesity (aRR 1.93; 95% CI; 1.24, 3.01) at 7 years.
   
   Who: mother-child pairs where the mother had gestational diabetes, Danish National Birth Cohort
   Effect: large for gestational age aRR 1.57 (1.05 to 2.35); overweight/obesity at 7 years aRR 1.93 (1.24 to 3.01)
   Certainty: High-risk group (GDM); replacing sweetened drinks with water was associated with a lower risk.
   Int J Epidemiol, 2017 · checked 2026-10-07 · we read the abstract
10. ev-aswp-10 · Observational data · prospective pre-birth cohort · n = 1683
    The highest quartile of NNS intake (Q4: 0.98 ± 0.91 servings/day) was associated with higher BMI z-score in infancy (β 0.20 units; 95% CI 0.02, 0.38), early childhood (0.21; 0.05, 0.37), mid-childhood (0.21; 0.02, 0.40), and early adolescence (0.14; -0.07, 0.35) compared with Q1 intake (Q1: 0.00 ± 0.00 servings/day).
    
    Who: mother-child pairs, Project Viva, Massachusetts, recruited 1999-2002
    Effect: highest vs lowest quartile: BMI z-score +0.20 in infancy, +0.21 in mid-childhood; +0.14 (-0.07 to 0.35) in early adolescence
    Certainty: Observational data; in adolescence the interval crosses zero.
    Int J Obes (Lond), 2022 · checked 2026-10-07 · we read the abstract
11. ev-aswp-11 · Observational data · secondary analysis of a prospective cohort · n = 1472
    The adjusted model showed a significant association between the consumption of any NNS and sucralose and the risk of GDM (OR for any NNS = 1.58; 95% CI: 1.10-2.26; P = 0.014; OR sucralose = 1.44; 95% CI 1.06-1.95; P = 0.020).
    
    Who: pregnant women in primary care, Santiago, Chile (CHiMINCs-II); sucralose the most used
    Effect: any NNS OR 1.58 (95% CI 1.10 to 2.26); sucralose OR 1.44 (1.06 to 1.95)
    Certainty: A single 24-hour survey; reverse causality (women at risk choosing sweeteners) is possible.
    Nutrition, 2024 · checked 2026-10-07 · we read the abstract
12. ev-aswp-12 · Observational data · non-randomized clinical pharmacokinetic study · n = 28
    We found that fetal plasma concentrations had a significant, positive, linear dependency on the maternal plasma concentrations of all four artificial sweeteners, with adjusted coefficients of 0.49 (CI: 0.28–0.70) for acesulfame, 0.72 (CI: 0.48–0.95) for cyclamate, 0.51 (CI: 0.38–0.67) for saccharin, and 0.44 (0.33–0.55) for sucralose (Figure 2 and Table 3).
    
    Who: pregnant women at planned cesarean section, Denmark; 19 given a drink with artificial sweeteners, 9 controls
    Effect: fetal vs maternal plasma coefficients: acesulfame 0.49, cyclamate 0.72, saccharin 0.51, sucralose 0.44
    Certainty: Shows that the fetus receives sweeteners, not harm; small sample, study stopped earlier than planned.
    Nutrients, 2023, Transplacental Transport of Artificial Sweeteners · checked 2026-10-07 · we read the fulltext
13. ev-aswp-13 · Observational data · secondary analysis of a randomized controlled trial · n = 571
    One-third of all pregnant women consumed LCS across each trimester of pregnancy.
    
    Who: pregnant women in the ROLO trial (low-GI dietary advice vs usual care), 3-day food diaries each trimester
    Effect: about 1 in 3 consumed LCS foods; trimester 2 users higher with advice than control (p < 0.001); main sources diet fruit drinks, diet cola, low-calorie yogurt
    Certainty: About prevalence and influence of dietary advice, not health consequences.
    Eur J Clin Nutr, 2022 · checked 2026-10-07 · we read the abstract
14. ev-aswp-14 · Position of an expert body · agency systematic review (USDA NESR, 2025 Dietary Guidelines Advisory Committee) · n = —
    Conclusion statements could not be drawn for these populations due to a lack of evidence.
    
    Who: individuals during pregnancy and postpartum; outcomes gestational weight gain and postpartum weight change
    Effect: no conclusion statement possible (insufficient evidence)
    Certainty: Knowledge boundary: the body explicitly records a lack of studies in pregnant women.
    USDA Nutrition Evidence Systematic Review, Low- and No-Calorie Sweetened Beverages and Growth, Body Composition, and Risk of Obesity, 2024 · checked 2026-10-07 · we read the section
15. ev-aswp-15 · Position of an expert body · agency risk assessment · n = —
    With respect to pregnancy, the Panel noted that there was no risk to the developing foetus from exposure to phenylalanine derived from aspartame at the current ADI (with the exception of women suffering from PKU).
    
    Who: pregnant women
    Effect: no fetal risk at ADI 40 mg/kg bw/day; exception: women with phenylketonuria
    Certainty: EFSA 2013, full reevaluation of aspartame; says nothing about other sweeteners.
    EFSA, full risk assessment of aspartame, press release 10 December 2013 · checked 2026-10-07 · we read the section
16. ev-aswp-16 · Position of an expert body · agency consumer guidance · n = —
    However, people with difficulty metabolizing phenylalanine because of a rare genetic disorder called phenylketonuria (PKU) should avoid or restrict aspartame.
    
    Who: people with phenylketonuria, including pregnant women with PKU
    Effect: avoid or restrict aspartame
    Certainty: Concerns aspartame only; for the other permitted sweeteners FDA gives the ADI.
    US FDA, Aspartame and Other Sweeteners in Food · checked 2026-10-07 · we read the section
17. ev-aswp-17 · Position of an expert body · WHO guideline · n = —
    The recommendation applies to all people except individuals with pre-existing diabetes and includes all synthetic and naturally occurring or modified non-nutritive sweeteners that are not classified as sugars found in manufactured foods and beverages, or sold on their own to be added to foods and beverages by consumers.
    
    Who: all people except individuals with pre-existing diabetes
    Effect: recommends against NSS for weight control or NCD risk reduction (conditional)
    Certainty: About weight control, not safety in pregnancy.
    WHO, WHO advises not to use non-sugar sweeteners for weight control in newly released guideline, 15 May 2023 · checked 2026-10-07 · we read the section