Adherence to the Mediterranean Diet and IVF Success Rate Among Non-obese Women Attempting Fertility

Dimitrios Karayiannis; Meropi D. Kontogianni; Christina Mendorou; Minas Mastrominas; Nikos Yiannakouris

Disclosures

Hum Reprod. 2018;33(3):494-502. 

In This Article

Abstract and Introduction

Abstract

Study Question Is adherence to the Mediterranean diet (MedDiet) associated with better IVF performance in women attempting fertility?

Summary Answer Greater adherence to the MedDiet, defined using the validated Mediterranean diet score (MedDietScore), was associated with a higher likelihood of achieving clinical pregnancy and live birth among non-obese women <35 years of age.

What is Known Already Diet impacts fertility and certain nutrients and food groups appear to have a greater effect on reproductive health, but there are relatively few published data on the role of dietary patterns, and the MedDiet in particular, on assisted reproductive performance.

Study Design, Size, Duration This prospective cohort study included 244 non-obese women (22–41 years of age; BMI < 30 kg/m2) who underwent a first IVF treatment in an Assisted Conception Unit in Athens, Greece, between November 2013 and September 2016. The study was designed to evaluate the influence of habitual dietary intake and lifestyle on fertility outcomes.

Participants/Materials, Setting, Methods Diet was assessed before the IVF treatment via a validated food-frequency questionnaire. Adherence to the MedDiet was assessed through the MedDietScore (range: 0–55), with higher scores indicating greater adherence. Intermediate outcomes (oocyte yield, fertilization rate and embryo quality measures) and clinical endpoints (implantation, clinical pregnancy and live birth) were abstracted from electronic medical records. Associations between MedDietScore and IVF outcomes were analysed using generalized linear models adjusting for age, ovarian stimulation protocol, BMI, physical activity, anxiety levels, infertility diagnosis, caloric intake and supplements use.

Main Results and the Role of Chance No association of MedDietScore with any of the intermediate outcomes or with implantation was found. However, compared with women in the highest tertile of the MedDietScore (≥36, n = 86), women in the lowest tertile (≤30, n = 79) had significantly lower rates of clinical pregnancy (29.1 vs 50.0%, P = 0.01) and live birth (26.6 vs 48.8%, P = 0.01). The multivariable-adjusted relative risk (95% CI) for clinical pregnancy comparing women in the lowest with women in the highest tertile of the MedDietScore was 0.35 (0.16–0.78; P-trend=0.01), and for live birth it was 0.32 (0.14–0.71; P-trend = 0.01). These associations were significantly modified by women's age (P-interaction <0.01 for both outcomes). MedDietScore was positively related to clinical pregnancy and live birth among women <35 years old (P ≤ 0.01) but not among women ≥35 years. Among women <35 years, a beneficial 5-point increase in the MedDietScore was associated with ~2.7 times higher likelihood of achieving clinical pregnancy and live birth.

Limitations, Reasons for Caution Our finding cannot be generalized to the whole reproductive population nor to obese women nor to women attending infertility clinics around the world. In addition, due to the observational study design, causal inference is limited.

Wider Implications of the Findings The results suggest that diet modifications and greater compliance to the Mediterranean diet may help increase the chances of a successful pregnancy and delivering a live baby for women undergoing IVF treatment.

Study Funding/Competing Interest(S) This work was partially supported by a grand from Harokopio University (KE321). All authors declare no conflicts of interest.

Introduction

Lifestyle factors including diet, smoking, exercise and stress affect reproductive performance, also during assisted reproduction (Klonoff-Cohen, 2005; Hornstein, 2016). Several recent reports have suggested that preconception dietary habits may influence IVF outcome, such as oocyte and embryo quality, implantation and successful completion of pregnancy (Braga et al., 2015; Firns et al., 2015; Hornstein, 2016; Garruti et al., 2017; Machtinger et al., 2017).

Most of the work on this topic has focused on the role of isolated nutrients (Hammiche et al., 2011) or food groups like dairy (Afeiche et al., 2016) and whole grains (Gaskins et al., 2016). There are also some epidemiological studies considering nutrition in the light of a more holistic approach that focuses on the role of dietary patterns rather than individual nutrients, foods or groups (Vujkovic et al., 2010; Toledo et al., 2011; Twigt et al., 2012; Parisi et al., 2017), as this approach probably better reflects long-term eating habits and behaviours. Among dietary patterns, the Mediterranean diet (MedDiet), a diet rich in vegetables, fruits, whole grains, legumes, nuts and olive oil, and low in red meat, seems to be the most promising and widely accepted for its positive effects on human health (García-Fernández et al., 2014). Previously, Vujkovic et al. (2010) have investigated the association between preconception dietary patterns and IVF outcomes among subfertile couples in the Netherlands, and showed that high adherence by the couple to a 'Mediterranean' type pattern (defined using principal component analysis) increased the probability of pregnancy. A comparable effect for the adherence to a healthy diet and the chance of ongoing pregnancy following IVF was subsequently found in a Dutch cohort of couples receiving their first IVF treatment, by calculating a preconception dietary risk score based on dietary recommendations of the Netherlands Nutrition Centre (Twigt et al., 2012). However, more studies are needed to confirm the favourable role of a MedDiet on assisted reproductive performance in other populations. Moreover, given obesity's high impact on female reproductive potential (Maheshwari et al., 2007; Broughton and Moley, 2017; Luke, 2017) it is essential to clarify the role and the potential mechanism(s) by which diet quality, and the MedDiet in particular, may exert beneficial effects on assisted reproduction outcome beyond body weight.

Therefore, the aim of the present study was to explore potential associations between MedDiet and IVF clinical outcomes among non-obese women of infertile couples attempting fertility. We hypothesized that greater adherence to the MedDiet, defined using an a-priori dietary pattern approach and calculation of the validated Mediterranean diet score (MedDietScore) (Panagiotakos et al., 2007), would favourably influence assisted reproductive performance of otherwise healthy women with no obesity problems.

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