A Randomized Placebo Controlled Pilot Study of Probiotic Supplementation in At-risk Pregnant Women

The most prevalent micronutrient deficiency in the United States (U.S.) is iron; a large majority of cases of iron deficiency (ID) and iron deficiency anemia (IDA) occur among pregnant women. During pregnancy, maternal iron stores are used for the growing fetus, maternal red blood cell (RBC) expansion, and placental growth and development, thus increasing the risk for ID and IDA. Across all trimesters of pregnancy in the U.S., it is estimated that 18% of individuals have ID and 5% have IDA, and within the third trimester, the prevalence of ID exceeds 27%. Prevalence of IDA is even greater among those who identify as Black or low-income. Maternal ID and IDA are associated with increased risk of preterm birth, low infant birth weight, maternal and fetal mortality, and irreversible infant neurocognitive defects. To meet this increasing requirement for iron and to optimize maternal iron nutrition, the Recommended Dietary Allowance for pregnancy is 27 mg/day of iron. However, given the continued high rates of maternal ID and IDA and only modest adherence to daily prenatal vitamins containing iron, alternative approaches to optimizing iron nutrition in pregnancy are needed.

Research has shown that one-time or short-term dosing of the probiotic Lactobacillus plantarum 299v (Lp299v) enhances iron absorption in non-pregnant populations. However, few studies have examined the effect of long-term supplementation on body iron stores. While probiotics are considered safe to consume in pregnancy, only one Lp299v supplementation trial has been conducted during the gestational period to evaluate its effects on maternal iron stores and risk of IDA. This study, among iron-sufficient pregnant Swedish women, showed a significantly lower decline in iron stores and a significantly lower prevalence of IDA in the third trimester among those randomized to Lp299v compared to standard care control.

These results offer potential positive effects for the role of Lp299v in maintaining maternal iron status among those starting pregnancy with sufficient iron stores and who receive care in a decentralized publicly funded healthcare system. However, no studies have evaluated the effect of Lp299v on maternal iron status among individuals at risk for IDA in pregnancy in the U.S., nor have studies extended findings to neonatal iron status. Moreover, it is unknown if positive feasibility and preliminary efficacy would persist in a U.S.-based health care setting with racially, ethnically, and socioeconomically diverse pregnant individuals. Therefore, the objectives of this study were as follows. First and foremost, we examined the feasibility of daily oral Lp299v maternal supplementation taken from the early second trimester through birth. Second, we explored the preliminary efficacy of Lp299v intake on maternal (at-risk for IDA defined as hemoglobin (Hb) between 10.0-12.0 g/dL) and neonatal cord hematological and iron status parameters compared to controls in an urban U.S. academic medical center with a racially, ethnically, and socioeconomically diverse patient population.

Inclusion criteria

• a 1st trimester hemoglobin (Hb) of 10.0 - 11.9 g/dl demonstrating ID or risk for prenatal ID
• singleton
• naturally conceived pregnancy
• < 20 weeks gestation
• 18 - 45 years of age
• sufficient fluency in English to complete study forms
• refrain from non-study dietary and pre-/probiotic supplements while enrolled in the study

Exclusion criteria

• oral antibiotic use within the past 2 months
• autoimmune disease
• infection
• receiving steroid treatment
• bariatric surgery
• inflammatory bowel disease
• hyperemesis
• hematologic disorder (e.g., sickle cell disease)
• current tobacco use
• substance abuse in the last 6 months
• other chronic disorders such as type 2 diabetes