Should you take zinc during pregnancy?

Not as a routine extra on top of a normal pregnancy diet. The 2021 Cochrane review of 25 randomized trials found zinc supplements may make little or no difference to preterm birth, with a risk ratio of 0.87 and an interval from 0.74 to 1.03 that includes no effect, on low-certainty evidence. With moderate certainty, they probably make no difference to low birthweight or to babies born small for their age. Your need for zinc does rise in pregnancy, by 3 mg a day.

Myth. The idea that every pregnant woman should add a zinc pill is not supported. The Cochrane authors concluded there is not enough evidence that zinc supplements in pregnancy improve outcomes for mothers or newborns, and WHO does not recommend them as part of routine antenatal care.

What the trials found

The Cochrane review

The 2021 review compared zinc with placebo or no zinc in healthy pregnant women, started before 27 weeks. For preterm birth it pooled 21 trials with 9,851 women and found a risk ratio of 0.87 (95% CI 0.74 to 1.03). For low birthweight, 17 trials with 7,399 women gave 0.94 (0.79 to 1.13). For babies small for gestational age, 9 trials with 5,330 women gave 1.02 (0.92 to 1.12). Very few trials enrolled women whose zinc was already adequate, so the review could not test whether zinc helps only those who are short of it.

The answer has moved. The 2015 version of the same review reported a 14% relative drop in preterm birth, and its authors said that signal came mainly from trials in women on low incomes, with some relevance where many babies die around birth. Once more trials were added in 2021, the estimate crossed the line of no effect.

Unsettled. A 2025 meta-analysis of 77 trials reached a more positive view. Its authors report that zinc alone was linked to less fetal growth restriction and longer babies at birth, and that adding zinc to iron and folic acid gave no extra benefit. Its abstract gives no certainty ratings, and the Cochrane review used stricter rules for which trials count. Until the two are reconciled, the more cautious review is the one to lean on.

Does the pill raise zinc at all

Two trials in low-resource settings suggest it raises blood zinc less than you might expect. In the Women First trial in Guatemala, India and Pakistan, women took a daily supplement with 15 mg of zinc for at least 7 months and high rates of low blood zinc were still seen late in pregnancy. In Ghana, a multiple micronutrient tablet with 30 mg of zinc taken for at least 16 weeks did not raise plasma zinc compared with iron and folic acid, and zinc deficiency became more common as pregnancy went on. In both, zinc came mixed with other nutrients.

In one small double-blind trial in Indonesia, 71 pregnant women with low blood zinc took 20 mg a day or placebo for 12 weeks. Median birth length was 19 in (49.3 cm) against 19 in (48.3 cm). The trial measured no outcomes such as preterm birth.

Gestational diabetes

A meta-analysis of 5 small randomized trials in 263 women with gestational diabetes found zinc, in some trials combined with other nutrients, lowered fasting glucose, insulin and insulin resistance. It reported standardized effects only and did not pool birth outcomes, so it says nothing yet about babies.

Who should be careful

Not for everyone. Doses add up. According to NIH ODS, the upper limit for adults is 40 mg of zinc a day, and 50 mg or more over weeks can block copper absorption, weaken immune function and lower HDL cholesterol. That limit also applies to pregnant women aged 19 and over, adolescents have lower limits of up to 34 mg, and zinc in a prenatal multivitamin counts toward it alongside any separate zinc pill.

Not for everyone. Zinc and some antibiotics block each other. NIH ODS says quinolone and tetracycline antibiotics should be taken at least 2 hours before or 4 to 6 hours after a zinc supplement. Tetracyclines are usually avoided in pregnancy anyway, so the timing rule matters most for quinolones.

Iron works the other way. WHO notes that routine iron supplements in pregnancy may stop women meeting their zinc needs, because iron competes with zinc for absorption. That is a statement in the guideline background with no size attached, and it is the reason zinc questions come up at all for women taking iron.

What expert bodies say

WHO does not recommend zinc supplements as part of routine antenatal care, and recommends them only within rigorous research. That 2016 position was kept by the 2021 guideline group. WHO also notes that the body's need for zinc roughly doubles in the third trimester. NIH ODS says pregnant women need 3 mg a day more zinc than other women of the same age. Its fact sheet still says routine zinc might lower preterm birth, a sentence that relays the 2015 Cochrane wording, which the 2021 update no longer supports.

How we searched

What would change this answer

• Trials that sort women by zinc status at the start. The Cochrane review could not test whether zinc helps only women who are short of it, because almost no trials enrolled women with adequate zinc.
• A reconciliation of the 2025 meta-analysis with Cochrane on fetal growth, ideally a Cochrane update that applies the same rules to the newer trials.
• Trials of zinc taken alongside routine iron, which competes with it for absorption, and of why pills raised blood zinc so little in Guatemala, India, Pakistan and Ghana.
• Birth outcomes from the gestational diabetes trials, which so far report blood sugar only.

How much zinc you need, where it comes from in food and what too much does are in the zinc guide.

Sources

1. ev-znpg-01 · Meta-analysis or systematic review · Cochrane systematic review and meta-analysis of randomized controlled trials · n = 9851
   The evidence suggests that zinc supplementation may result in little or no difference in reducing preterm births (risk ratio (RR) 0.87, 95% confidence interval (CI) 0.74 to 1.03; 21 studies, 9851 participants; low-certainty evidence).
   
   Who: healthy pregnant women given zinc versus no zinc or placebo before 27 weeks' gestation
   Effect: preterm birth RR 0.87 (95% CI 0.74 to 1.03); 21 studies, 9,851 participants; low-certainty evidence
   Certainty: Best synthesis; risk of bias low in half of the trials; search to July 2020.
   Cochrane Database Syst Rev, 2021 · checked 2026-10-07 · we read the abstract
2. ev-znpg-02 · Meta-analysis or systematic review · Cochrane systematic review and meta-analysis of randomized controlled trials · n = 7399
   and probably makes little or no difference in reducing the risk of low birthweight (RR 0.94, 95% CI 0.79 to 1.13; 17 studies, 7399 participants; moderate-certainty evidence) and small-for-gestational age babies when compared to placebo or no zinc supplementation (RR 1.02, 95% CI 0.92 to 1.12; 9 studies, 5330 participants; moderate-certainty evidence).
   
   Who: pregnant women in randomized trials of zinc versus placebo or no zinc
   Effect: low birthweight RR 0.94 (95% CI 0.79 to 1.13), 17 studies, 7,399 participants; SGA RR 1.02 (95% CI 0.92 to 1.12), 9 studies, 5,330; moderate certainty
   Certainty: Moderate certainty for both outcomes.
   Cochrane Database Syst Rev, 2021 · checked 2026-10-07 · we read the abstract
3. ev-znpg-03 · Meta-analysis or systematic review · Cochrane systematic review and meta-analysis of randomized controlled trials · n = over 18,000
   There is not enough evidence that zinc supplementation during pregnancy results in improvements in maternal or neonatal outcomes.
   
   Who: pregnant women in 25 randomized trials, over 18,000 women and their babies
   Effect: no maternal or neonatal benefit shown; stillbirth RR 1.22 (95% CI 0.80 to 1.88), low certainty
   Certainty: No subgroup analysis by zinc status was possible: very few trials in women with normal zinc.
   Cochrane Database Syst Rev, 2021 · checked 2026-10-07 · we read the abstract
4. ev-znpg-04 · Meta-analysis or systematic review · Cochrane systematic review and meta-analysis of randomized controlled trials · n = 7637
   The evidence for a 14% relative reduction in preterm birth for zinc compared with placebo was primarily represented by trials involving women of low income and this has some relevance in areas of high perinatal mortality.
   
   Who: pregnant women in 16 randomized trials, mainly in low-income settings
   Effect: preterm birth RR 0.86 (95% CI 0.76 to 0.97), 16 trials, 7,637 women; no reduction in low birthweight (RR 0.93)
   Certainty: Superseded by the 2021 update (ev-znpg-01); kept to show how the estimate moved.
   Cochrane Database Syst Rev, 2015 · checked 2026-10-07 · we read the abstract
5. ev-znpg-05 · Meta-analysis or systematic review · systematic review and meta-analysis of randomized controlled trials (Cochrane RoB 2) · n = 77 RCTs
   No additional benefits observed with zinc-iron-folate combinations versus iron-folate alone.
   
   Who: pregnant women in randomized controlled trials of prenatal zinc supplementation
   Effect: fetal growth restriction RR 0.23 (95% CI 0.16 to 0.35); birth length SMD 0.66 (95% CI 0.21 to 1.12); no added benefit of zinc-iron-folate vs iron-folate
   Certainty: No GRADE ratings in the abstract; includes many small trials; results differ from Cochrane 2021, which used stricter inclusion.
   J Evid Based Med, 2025 · checked 2026-10-07 · we read the abstract
6. ev-znpg-06 · Meta-analysis or systematic review · systematic review and meta-analysis of randomized controlled trials · n = 263
   Five RCTs involving 263 patients are included in the meta-analysis.
   
   Who: women with gestational diabetes in randomized controlled trials of zinc or zinc combinations versus placebo
   Effect: fasting glucose SMD -0.52 (95% CI -0.82 to -0.21); insulin SMD -0.68; HOMA-IR SMD -0.77; no effect on LDL or total cholesterol
   Certainty: 5 small trials, some with zinc combined with other nutrients; standardized effects only; birth outcomes not pooled.
   J Matern Fetal Neonatal Med, 2021 · checked 2026-10-07 · we read the abstract
7. ev-znpg-07 · Randomized controlled trial(s) · randomized controlled trial (secondary analysis) · n = 838
   Despite daily zinc supplementation for ≥7 mo, high rates of maternal hypozincemia were observed.
   
   Who: women in low-resource settings randomized to a lipid-based supplement with 15 mg zinc from before conception, from 12 weeks, or none
   Effect: serum zinc at 34 weeks 50.3 and 50.8 vs 47.8 ug/dL (P = 0.005); hypozincemia at 34 weeks 36% to 74% by site
   Certainty: Zinc given within a multi-nutrient lipid supplement; n is the 34-week sample.
   J Nutr, 2024 · checked 2026-10-07 · we read the abstract
8. ev-znpg-08 · Randomized controlled trial(s) · randomized controlled trial (iLiNS-DYAD, subset analysis) · n = 250
   Daily MMS supplementation for ≥16 wk during pregnancy did not significantly increase plasma zinc concentrations, and the prevalence of zinc deficiency increased over the course of pregnancy.
   
   Who: pregnant women in Ghana randomized to multiple micronutrients with 30 mg/day zinc or iron and folic acid
   Effect: plasma zinc at 36 weeks 52.9 vs 52.2 ug/dL (P = 0.25); zinc deficiency 38.4% vs 43.0% (P = 0.24)
   Certainty: Subset of 125 women per group; zinc given with other micronutrients.
   J Nutr, 2026 · checked 2026-10-07 · we read the abstract
9. ev-znpg-09 · Randomized controlled trial(s) · randomized double-blind placebo-controlled trial · n = 71
   The comparison of mean cord blood osteocalcin levels and median neonatal birth lengths in the supplementation group was higher than in the placebo group: 131.8±35.3 vs 90.6±35.4 ng/ml (p=0.001) and 49.3 (46.5-51.3) vs 48.3 (46-50.8) cm (p=0.004), respectively.
   
   Who: pregnant women in the second or third trimester, mean serum zinc 54.6 ug/dL
   Effect: median birth length 19 vs 19 in (49.3 vs 48.3 cm) (p = 0.004); serum zinc 59.1 vs 50 ug/dL after 12 weeks
   Certainty: Small single-center trial; no clinical outcomes such as preterm birth.
   Med Glas (Zenica), 2021 · checked 2026-10-07 · we read the abstract
10. ev-znpg-10 · Position of an expert body · WHO guideline evidence-to-decision framework · n = —
    WHO does not recommend zinc supplementation as part of routine ANC. Zinc supplementation is recommended only in the context of rigorous research to improve our knowledge of its effect in pregnant women.
    
    Who: pregnant women receiving routine antenatal care
    Effect: recommendation: not for routine use; research context only
    Certainty: 2016 WHO ANC recommendation retained by the 2021 guideline group.
    World Health Organization, WHO antenatal care recommendations for a positive pregnancy experience. Nutritional interventions update: zinc supplements during pregnancy, 2021 · checked 2026-10-07 · we read the section
11. ev-znpg-11 · Position of an expert body · WHO guideline evidence-to-decision framework · n = —
    In addition, routine iron supplementation may prevent women from meeting their zinc requirements by competing with zinc for absorption (3).
    
    Who: pregnant women taking routine iron supplements
    Effect: competition for absorption; also with calcium supplements
    Certainty: Background statement of the guideline; no effect size.
    World Health Organization, WHO antenatal care recommendations for a positive pregnancy experience. Nutritional interventions update: zinc supplements during pregnancy, 2021 · checked 2026-10-07 · we read the section
12. ev-znpg-12 · Position of an expert body · WHO guideline evidence-to-decision framework · n = —
    In pregnant women, the average physiological requirement of zinc is estimated to double in the third trimester and almost triple during lactation (2).
    
    Who: pregnant and lactating women
    Effect: requirement about 2x in the third trimester, almost 3x in lactation
    Certainty: Background statement; zinc is not stored in the body.
    World Health Organization, WHO antenatal care recommendations for a positive pregnancy experience. Nutritional interventions update: zinc supplements during pregnancy, 2021 · checked 2026-10-07 · we read the section
13. ev-znpg-13 · Position of an expert body · agency fact sheet · n = —
    Routine zinc supplementation during pregnancy does not appear to reduce the risk of low birthweight, stillbirth, or neonatal death, but it might lower the risk of preterm birth [41].
    
    Who: pregnant and lactating women in the United States
    Effect: +3 mg/day in pregnancy, +4 mg/day in lactation; 11% of pregnant women below the EAR (NHANES 2001-2014)
    Certainty: Fact sheet cites the older Cochrane wording; the 2021 update no longer supports a preterm effect.
    NIH Office of Dietary Supplements, Zinc Fact Sheet for Health Professionals · checked 2026-10-07 · we read the section
14. ev-znpg-14 · Position of an expert body · agency fact sheet · n = —
    During pregnancy, the amount of zinc needed increases to accommodate fetal growth, and the FNB therefore recommends that pregnant women consume 3 mg/day more zinc than nonpregnant women in the same age group [1,3].
    
    Who: pregnant women
    Effect: +3 mg/day
    Certainty: FNB requirement relayed by ODS.
    NIH Office of Dietary Supplements, Zinc Fact Sheet for Health Professionals · checked 2026-10-07 · we read the section
15. ev-znpg-15 · Position of an expert body · agency fact sheet · n = —
    Doses of 50 mg of zinc or more over a period of weeks can inhibit copper absorption, reduce immune function, and lower high-density lipoprotein cholesterol levels; however, it is unlikely that a person would obtain this much zinc from food alone. The Tolerable Upper Intake Level for zinc is 40 mg for adults, and it ranges from 4 to 34 mg for infants, children, and adolescents, depending on age.
    
    Who: adults; children and adolescents have upper limits of 4 to 34 mg
    Effect: UL 40 mg/day adults; 50 mg/day or more for weeks impairs copper absorption, immune function and HDL
    Certainty: Adult UL also applies in pregnancy (19 and older); zinc from a prenatal multivitamin and a separate zinc pill adds up.
    NIH Office of Dietary Supplements, Zinc Fact Sheet for Health Professionals · checked 2026-10-07 · we read the section
16. ev-znpg-16 · Position of an expert body · agency fact sheet · n = —
    Both quinolone antibiotics (such as Cipro) and tetracycline antibiotics (such as Achromycin and Sumycin) might interact with zinc in the gastrointestinal tract, which could inhibit the absorption of both zinc and the antibiotic if they are taken at the same time [103,104]. Taking the antibiotic at least 2 hours before or 4 to 6 hours after the zinc supplement minimizes this interaction [103].
    
    Who: people taking zinc supplements with quinolone or tetracycline antibiotics
    Effect: reduced absorption of both; separate by 2 h before or 4 to 6 h after
    Certainty: Tetracyclines are usually avoided in pregnancy anyway; the timing rule matters for quinolones and other chelating drugs.
    NIH Office of Dietary Supplements, Zinc Fact Sheet for Health Professionals · checked 2026-10-07 · we read the section