Mediterranean Diet Linked to Reduce Risk of Adverse Pregnancy Outcomes in Nulliparous Women

Natalie Bello, MD, MPH

A study of geographically, racially, and ethnically diverse nulliparous women in the US suggests adherence to a Mediterranean diet around the time of conception and during pregnancy could reduce risk of adverse pregnancy outcomes.

An assessment of the influence of diet among women included in the Nulliparous Pregnancy Outcomes Study: Monitoring Mothers-to-Be (nuMoM2b), results of the study indicate adherence to a Mediterranean diet was associated with a 20% or greater reduction in odds of gestational diabetes, preeclampsia, and any adverse pregnancy outcome.

“We also looked at the individual components of the Mediterranean diet and found higher intakes of vegetables, legumes and fish were related to lower associated risk of an adverse pregnancy outcome,” said senior investigator Natalie Bello, MD, MPH, director of Hypertension Research in the Smidt Heart Institute, in a statement from Cedars Sinai.

Launched in 2010 with the intent of learning more about risk factors and mechanisms of common adverse pregnancy outcomes in nulliparous women, the nuMoM2b was designed as a prospective, multicenter, cohort study. With enrollment occurring from October 1, 2010-September 30, 2013, the trial enrolled 10,038 women from 8 clinical research sites and 12 subsites around the US.

The current study included 7798 of the 10,038 who had complete dietary information, which was collected using the modified Block 2005 Food Frequency Questionnaire at the first study visit between 6 weeks and 13 weeks plus 6 days of gestation. This cohort had a mean age of 27.4 (SD, 5.5) years, 9.7% were aged 35 years or older at enrollment, 10.5% were non-Hispanic Black women, 16.6% were Hispanic, and 19.5% had obesity at baseline.

Leveraging data from the food frequency questionnaire, Alternate Mediterranean Diet (aMed) scores were computed for participants. These scores ranged from 0-9, with investigators further stratifying participants into groups based on scores, defined as low (0-3), moderate (4-5), or high (6-9). The study cohort had a mean aMed score of 4.3 (SD, 2.1), with 30.6%, 31.2%, and 38.2% of the cohort being classified as having high, moderate, and low concordance to a Mediterranean diet pattern, respectively.

The primary outcome of interest for the study was incidence of any adverse pregnancy outcomes, which included preeclampsia or eclampsia, gestational hypertension, gestational diabetes, preterm birth, delivery of a small-for-gestational-age infant, or stillbirth. For the purpose of analysis, incidence of the aforementioned outcomes separately served as secondary outcomes of interest. Investigators noted associations of aMed score with adverse pregnancy outcomes were assessed with univariable and multivariable logistic regression models.

In multivariable-adjusted models, results indicated those with high aMed scores had a 21% lower likelihood of experiencing any adverse pregnancy outcome than their counterparts with a low concordance (aOR, 0.79 [95% CI, 0.68-0.92]). Analysis of secondary end points demonstrated a high level of concordance was associated with a 28% reduction in odds of preeclampsia or eclampsia (aOR, 0.72 [95% CI, 0.55-0.93]) and a 37% reduction in odds of gestational diabetes (aOR, 0.63 [95% CI, 0.44-0.90]) relative to those with a low score.

Further analysis examining associations by patient subgroup revealed there were no significant differences by race, ethnicity, and prepregnancy body mass index. However, investigators pointed out stronger associations were observed with high concordance to Mediterranean diet among women aged 35 years or older (aOR, 0.54 [95% CI, 0.34-0.84]; P=.02). In additional analyses assessing aMed scores as quintiles produced similar associations, with higher scores inversely associated with incidence of any adverse pregnancy outcome.

“This multicenter, population-based study validates that a healthier eating pattern is associated with a lower risk of adverse pregnancy outcomes, the most exciting being a 28% lower risk for preeclampsia,” Bello said. “Importantly, this connection between the Mediterranean diet and lower risk of adverse pregnancy outcomes was seen in a geographically, racially and ethnically diverse population.”

This study, “Association of a Mediterranean Diet Pattern With Adverse Pregnancy Outcomes Among US Women,” was published in JAMA Network Open.