Table 1.

Results for fertility outcomes stratified by nutritional component in spontaneously conceiving women.

Category	Studies	Fertility	Clinical pregnancy	Live birth	Time to pregnancy	Fecundability	Early pregnancy loss and stillbirth
ENERGY AND MACRONUTRIENTS
Energy density	1	–	NS: continuous. −ve: categorical >1.6 vs 1.37–1.6 (Hartman et al., 2021).	−ve: third vs second energy density tertile (Hartman et al., 2021).	NS: continuous +ve: categorical >1.6 vs 1.36–1.6 kcal/g (Hartman et al., 2021).	–	–
Protein	1	−ve: increasing animal protein (Chavarro et al., 2008). +ve: increasing vegetable protein (Chavarro et al., 2008).	–	–	–	–	–
CHO	2	−ve: increasing % CHO (Chavarro et al., 2009).	–	–	–	−ve: increasing added sugar (g/day) (Willis et al., 2020). −ve: categorical increasing CHO-fiber ratio (Willis et al., 2020).	–
GI/GL	2	−ve: increasing GI only in nulliparous (Chavarro et al., 2009). –ve: increasing GL (Chavarro et al., 2009).	NS: GI and GL (Noli et al., 2020).	–	–	+ve: reduced categorical GL >141 vs >100 (Willis et al., 2020).	–
Fats/FAs	4	NS: total fat, cholesterol, most FAs (Chavarro et al., 2007c). −ve: increasing TFAs (total, in place of n-6 PUFAs) (Chavarro et al., 2007c). −ve: higher PUFAs, higher TFA in infertile women <50 years (Revonta et al., 2010).	–	–	–	−ve: increasing TFA (Wise et al., 2018). +ve: increasing omega-3 (Wise et al., 2018). NS: marine-sourced long chain fatty acids (Wise et al., 2020).	–
CORE FOOD GROUPS
Dairy	2	−ve: increasing low fat dairy (serving/week) ( Chavarro et al., 2007a). +ve: increasing high fat dairy foods (Chavarro et al., 2007a). +ve: increasing dairy fat (Chavarro et al., 2007a).	–	–	–	+ve: increasing dairy NS: low, high-fat dairy (Wise et al., 2017).	–
Fruits and vegetables	3	+ve: increasing fruit (Grieger et al., 2018). NS: fruits, vegetables (Revonta et al., 2010).	–	–	+ve: increasing fruit. NS: vegetable (Grieger et al., 2018).	–	+ve: low appetite for vegetables (Qu et al., 2019).
Fish/seafood	3	NS: fish (Grieger et al., 2018).	–	–	NS: fish (Grieger et al., 2018).	NS: total seafood, unfried shellfish. −ve: Increasing fried shellfish (Wise et al., 2020). +ve: Increased seafood servings/cycle (Gaskins et al., 2018).	–
DISCRETIONARY FOODS
Fast food/take-out	2	−ve: increasing fast food (Lee et al., 2020). –ve: increasing non-home prepared meals/day.	–	–	−ve: increasing fast food (Grieger et al., 2018).	−ve: Increasing non-home prepared meals/day.	–
Sugar-sweetened beverages	2	–	–	−ve: increasing SSB- fewer retrieved, mature, fertilized oocytes. NS: diet soda (Machtinger et al., 2017).	–	−ve: increasing SSB, soda. NS: sugar-sweetened fruit juice and energy drinks (Hatch et al., 2012). −ve: increasing SSB, soda (Hatch et al., 2018).	–
PHYTOESTROGENS
Soy and other	2	–	–	−ve: increasing isoflavone intake (g/day) (Jacobsen et al., 2014). NS: parity: isoflavone intake (g/day) (Jacobsen et al., 2014). −ve: nulligravidity higher with increasing isoflavone intake (g/day) (Jacobsen et al., 2014).	–	NS: phytoestrogen (Wesselink et al., 2020).	–
WHOLE DIETS
Fertility diet	2	+ve: increasing dietary adherence (Chavarro et al., 2007b).	–	–	–	–	NS: early pregnancy loss, spontaneous abortion, and stillbirth (Gaskins et al., 2014).
MedDiet/aMedDiet	2	–	+ve: increasing dietary adherence (Toledo et al., 2011).	–	–	–	NS: early pregnancy loss, spontaneous abortion, and stillbirth (Gaskins et al., 2014).
aHEI-2010	1	–	–	–	–	–	NS: early pregnancy loss, spontaneous abortion, and stillbirth (Gaskins et al., 2014).

aHEI-2010, alternative healthy eating index 2010; aMED, alternative Mediterranean diet; CHO, carbohydrates; FAs, fatty acids; GI/GL, glycemic index/glycemic load; MedDiet, Mediterranean diet; NS, not significant; −ve/+ve, negative/positive; PUFA, polyunsaturated fatty acid; SSB, sugar sweetened beverages; TFA, trans saturated fatty acid.