Nutrition for preconception and fertility
• Preconception period
o 3 months prior to conception
o Advice says to change lifestyle/diet 3 months before planning to try and conceive/come off
birth control
o Prepares body for pregnancy – preconception health can influence health of the baby
o Optimise fertility
o NHS advice for preconception
▪ Folic supplement – 400ug/day
▪ Stop smoking
▪ Cut out alcohol – from preconception as could still consume alcohol while
unknowingly be pregnant
▪ Keep to a healthy weight – BMI between 20-25
• Folate (folic acid)
o Deficiency associated with increased risk in neural tube defects (NTDs)
o Neural tube closed 21-27days post-conception – unknown why folate deficiency stops the
tube closing
o Evidence shows folic acid supplement reduced reoccurrence and first time occurrence of
NTDs
o 400ug/day folic acid from preconception → 1st trimester (100mg/day until birth)
o Women with BMI >39 at increased risk of NTDs so take 5mg/day supplement (only on
prescription)
• Weight guidance NICE
o Encourage women to be healthy weight prior to pregnancy
o Refer women with BMI >30 to care pathway – due to current high rates of maternal obesity,
NHS won’t refer unless >35
o Encourage women to become healthy weight after childbirth before next pregnancy
• Smoking (BMA, 2004)
o Women who smoke take longer to conceive
o Women who smoke as twice as likely to be infertile than non-smokers
o Men and women who smoke have poorer response to fertility treatment
o Women who have stopped smoking take no longer to conceive than women who never
smoked – no reproductive damage is permanent
o Stopping smoking improves sperm count and quality
• Alcohol and reproductive hormones
o Scheliep et al (2015)
▪ Alcohol intake significantly associated with higher free oestradiol, testosterone and
LH
▪ Lower risk of sporadic anovulation with higher alcohol intake (not significant)
o Anwar et al (2021)
▪ Moderate intake in luteal phase associated with reduced odds of conception
, ▪ Heavy intake during luteal phase or ovulatory phase associated with reduced odds of
conception – each additional day of ‘binge’ drinking associated with 19% reduction
in odds of conception
• Maternal diet
o Folate supplement
▪ Increase rate of conception
▪ Lower risk of sporadic anovulation
o Poly-unsaturated fatty acids (PUFA) supplementation improve oocyte quality and increase
rate of embryo implantation
o Meat
▪ More plant-based diet is preferential
▪ Meat reservoir of bacteria, uncooked = food poisoning
▪ Chavarro et al (2008) – women in highest quintile of animal protein intake at 38%
increased risk of ovulatory infertility
o Soy
▪ Women undergoing IVF with highest isoflavone intake from soy >7% more likely to
conceive
▪ Similar structure to oestrogen – binds receptors and elicits oestrogen response
• Paternal diet
o Antioxidant supplement – improve sperm quality by reducing oxidative agents
o Healthy dietary patterns – e.g., Mediterranean diet associated with better semen
parameters
o Focus less on supplements and more on healthy, balanced diet
• Overweight/obesity
o If either or both man and woman in couple are obese, this increases the time to conception
o Obese women who are infertile are advised to lose weight prior to fertility treatment
Nutrition for pregnancy
• Stages of pregnancy
o Preconception
o 1st trimester (0-12 weeks) – 0 week starts from last menstrual cycle
o 2nd trimester (13-37 weeks)
o 3rd trimester (28-40weeks)
o Birth at 37-42 weeks = full term
o Birth at <37 weeks = pre-term
• Placental villi extend into mother’s blood to absorb nutrients
• Preconception period
o 3 months prior to conception
o Advice says to change lifestyle/diet 3 months before planning to try and conceive/come off
birth control
o Prepares body for pregnancy – preconception health can influence health of the baby
o Optimise fertility
o NHS advice for preconception
▪ Folic supplement – 400ug/day
▪ Stop smoking
▪ Cut out alcohol – from preconception as could still consume alcohol while
unknowingly be pregnant
▪ Keep to a healthy weight – BMI between 20-25
• Folate (folic acid)
o Deficiency associated with increased risk in neural tube defects (NTDs)
o Neural tube closed 21-27days post-conception – unknown why folate deficiency stops the
tube closing
o Evidence shows folic acid supplement reduced reoccurrence and first time occurrence of
NTDs
o 400ug/day folic acid from preconception → 1st trimester (100mg/day until birth)
o Women with BMI >39 at increased risk of NTDs so take 5mg/day supplement (only on
prescription)
• Weight guidance NICE
o Encourage women to be healthy weight prior to pregnancy
o Refer women with BMI >30 to care pathway – due to current high rates of maternal obesity,
NHS won’t refer unless >35
o Encourage women to become healthy weight after childbirth before next pregnancy
• Smoking (BMA, 2004)
o Women who smoke take longer to conceive
o Women who smoke as twice as likely to be infertile than non-smokers
o Men and women who smoke have poorer response to fertility treatment
o Women who have stopped smoking take no longer to conceive than women who never
smoked – no reproductive damage is permanent
o Stopping smoking improves sperm count and quality
• Alcohol and reproductive hormones
o Scheliep et al (2015)
▪ Alcohol intake significantly associated with higher free oestradiol, testosterone and
LH
▪ Lower risk of sporadic anovulation with higher alcohol intake (not significant)
o Anwar et al (2021)
▪ Moderate intake in luteal phase associated with reduced odds of conception
, ▪ Heavy intake during luteal phase or ovulatory phase associated with reduced odds of
conception – each additional day of ‘binge’ drinking associated with 19% reduction
in odds of conception
• Maternal diet
o Folate supplement
▪ Increase rate of conception
▪ Lower risk of sporadic anovulation
o Poly-unsaturated fatty acids (PUFA) supplementation improve oocyte quality and increase
rate of embryo implantation
o Meat
▪ More plant-based diet is preferential
▪ Meat reservoir of bacteria, uncooked = food poisoning
▪ Chavarro et al (2008) – women in highest quintile of animal protein intake at 38%
increased risk of ovulatory infertility
o Soy
▪ Women undergoing IVF with highest isoflavone intake from soy >7% more likely to
conceive
▪ Similar structure to oestrogen – binds receptors and elicits oestrogen response
• Paternal diet
o Antioxidant supplement – improve sperm quality by reducing oxidative agents
o Healthy dietary patterns – e.g., Mediterranean diet associated with better semen
parameters
o Focus less on supplements and more on healthy, balanced diet
• Overweight/obesity
o If either or both man and woman in couple are obese, this increases the time to conception
o Obese women who are infertile are advised to lose weight prior to fertility treatment
Nutrition for pregnancy
• Stages of pregnancy
o Preconception
o 1st trimester (0-12 weeks) – 0 week starts from last menstrual cycle
o 2nd trimester (13-37 weeks)
o 3rd trimester (28-40weeks)
o Birth at 37-42 weeks = full term
o Birth at <37 weeks = pre-term
• Placental villi extend into mother’s blood to absorb nutrients
