Preconception Supplements Reduced Preterm Births But Not Gestational Diabetes

One of the researchers’ goals was to gather evidence about outcomes hypothesized to be gained by nutritional supplementation that starts preconception.

Preconception probiotics, micronutrients, and myo-inositol supplementation reduced preterm birth, but not gestational glycemia. These findings from a double-blind, randomized controlled trial were published in Diabetes Care.

Women (N=1729) planning to conceive during the next 6 months were recruited from centers in Singapore, New Zealand, and the UK between 2015 and 2017 for the Nutritional Intervention Preconception and During Pregnancy to Maintain Healthy Glucose Metabolism and Offspring Health (NIPPER) study.

Participants were randomly assigned in a 1:1 ratio to receive daily 400 mg folic acid, 12 mg iron, 150 mg calcium, 150 mg iodine, and 720 mg b-carotene alone or with 4 g myo-inositol, 10 mg vitamin D, 1.8 mg riboflavin, 2.6 mg vitamin B6, 5.2 mg vitamin B12, 10 mg zinc, and probiotics (Lactobacillus rhamnosus and Bifidobacterium animalis). Pregnancy outcomes and gestational glycemia were assessed.

A total of 34% of each cohort (n=588) reached 28 weeks’ gestation. Among those who reached 28 weeks, the control and intervention cohorts comprised women with mean ages of 30.14 (±3.30) and 30.53 (±3.40) years. Their median BMI was 23.75 (interquartile range [IQR], 21.34-27.5) and 23.65 (IQR, 21.16-26.23) kg/m2, and 27.2% and 19.1% had a family history of diabetes, respectively.

The participants were assessed by an oral glucose tolerance test (OGTT) at 3 time points. No significant group differences were observed (all P >.017).

Among women who were overweight or obese at the time of conception, 2-hour glycemia was higher among the intervention cohort (adjusted b, 0.076; 95% CI, 0.020-0.131 loge mmol/L). This significant difference did not associate with an increased risk for gestational diabetes.

Fewer women in the intervention group delivered their baby before 37 weeks (adjusted risk ratio [aRR], 0.43; 95% CI, 0.22-0.82). The group differences were more pronounced between 34 and 36 weeks (aRR, 0.41; 95% CI, 0.20-0.85) and for preterm prelabor rupture of membranes (aRR, 0.39; 95% CI, 0.16-0.97).

Major postpartum hemorrhage incidence (>1-L blood loss) was reduced among the intervention recipients (aRR, 0.44; 95% CI, 0.20-0.94).

This study may have been limited by its lack of diversity and small percentage of women who were not overweight or obese prior to conception.

These findings suggested supplementation with probiotics, micronutrients, and myo-inositol did not decrease likelihood of developing gestational diabetes but did decrease preterm deliveries.

Disclosure: Multiple authors declared affiliations with industry. Please refer to the original article for a full list of authors’ disclosures.


Godfrey KM, Barton SJ, El-Heis S, et al; NiPPeR Study Group. Myo-inositol, probiotics, and micronutrient supplementation from preconception for glycemia in pregnancy: NiPPeR international multicenter double-blind randomized controlled trial. Diabetes Care. Published online March 29, 2021. doi:10.2337/dc20-2515