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An Overview of The Relationship Between Fertility and Caffeine Intake


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Caffeine is a psychoactive component with a chemical composition of 1,3,7-trimethylxanthine. Coffee, tea, energy drink, and chocolate are the main sources of caffeine. There are several positive health effects of caffeine on diabetes, Parkinson’s disease, and cardiovascular disease. However, the relationship between caffeine consumption and reproductive health is controversial. The aim of the present study was to determine the effects of caffeine consumption on fertility. A literature search was conducted using the electronic databases PubMed, Web of Science, Cochrane, and LILACS with the search terms “fertility,” “infertility,” “fecundability,” “reproductive,” “caffeine,” “coffee,” “tea,” and “caffeinated.” An additional manual search was also performed for missing articles. At the end of the search, a total of 13 studies were included in the present study. Six studies reported negative and two studies reported positive effects of caffeine on fertility by several mechanisms such as affecting sex hormones and reducing clearance during the luteal phase. However, no association was found between caffeine and fertility or fecundability in five studies. According to study results that revealed negative effects of caffeine, it may be recommended to males and females who are planning to conceive to decrease caffeine intake, especially from coffee. It may also be recommended to consume other types of healthy beverages and foods without caffeine.
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An Overview of The Relationship Between Fertility and Caeine Intake
Fertilite ve Kafein Alımı Arasındaki İlişkinin Değerlendirilmesi
Melahat Sedanur Macit, Yasemin Akdevelioğlu
Deparment of Nutrition and Dietetics, Gazi University, Ankara, Turkey
Correspondence Author/ Sorumlu Yazar: Melahat Sedanur Macit E-mail/E-posta:
Received/Geliş Tarihi: 21.08.2017 Accepted/Kabul Tarihi: 12.11.2017 DOI: 10.5152/clinexphealthsci.2017.663
©Copyright by 2018 Journal of Marmara University Institute of Health Sciences - Available online at
©Telif Hakkı 2018 Marmara Üniversitesi Sağlık Bilimleri Enstitüsü - Makale metnine web sayfasından ulaşılabilir
Caeine is one of the most common psychoactive components. Its chemical composition is 1,3,7-trimethylxanthine, which is found in
more than 60 plants and also produced in the industry (1). After entering the body, caeine is easily distributed in the body and exists in
the saliva, breast milk, embryo, and neonate owing to its ability to pass all membranes including the placental barrier (2,3). Caeine is a
component present in a large range of food such as coees, teas, chocolates, cocoa products, and soft and energy drinks. However, coee
is its main source (4). Table 1 shows the amount of caeine in these main sources.
Caeine is associated with several positive health eects for cardiovascular diseases, diabetes, and Parkinson’s disease (7). It is an ad-
enosine receptor antagonist and may also have several eects on reproductive health (8). Adenosine has eects on sperm capacity
via tyrosine phosphorylation with N6-cyclopentyladenosine (9). For the rst time, the Food and Drug Administration advised pregnant
women to decrease caeine intake (10). It was also recommended that pregnant women should not exceed 200 mg/day caeine intake.
Caeine is presented as one of the nutrients that have eects on dysmenorrhea and premenstrual syndrome (11). In addition, it is re-
ported to decrease fertility (12). The relationship between caeine and fertility was rst reported by Wilcox et al. in a prospective study.
According to their study results, per cycle probability of conceiving was decreased by 50% due to drinking one cup of coee. However,
study results are controversial owing to its designs, methodological failings, and call of bias. Caeine intake, below the recommend-
Caeine is a psychoactive component with a chemical composition of
1,3,7-trimethylxanthine. Coee, tea, energy drink, and chocolate are the
main sources of caeine. There are several positive health eects of caeine
on diabetes, Parkinson’s disease, and cardiovascular disease. However, the
relationship between caeine consumption and reproductive health is
controversial. The aim of the present study was to determine the eects of
caeine consumption on fertility. A literature search was conducted using
the electronic databases PubMed, Web of Science, Cochrane, and LILACS
with the search terms “fertility,” “infertility,” “fecundability,” “reproductive,
“caeine,“coee,“tea,” and “caeinated.” An additional manual search was
also performed for missing articles. At the end of the search, a total of 13
studies were included in the present study. Six studies reported negative
and two studies reported positive eects of caeine on fertility by sever-
al mechanisms such as aecting sex hormones and reducing clearance
during the luteal phase. However, no association was found between caf-
feine and fertility or fecundability in ve studies. According to study results
that revealed negative eects of caeine, it may be recommended to males
and females who are planning to conceive to decrease caeine intake, es-
pecially from coee. It may also be recommended to consume other types
of healthy beverages and foods without caeine.
Keywords: Caeine, coee, fertility, fecundability, pregnancy
Kafein 1,3,7-trimetilksantin kimyasal yapısında, biyoaktif bir bileşendir.
Kahve, çay, enerji içecekleri ve çikolata kafeinin ana kaynaklarıdır. Kafein
diyabet, Parkinson, kardiyovasküler hastalıklar gibi sağlık sorunları üzerine
olumlu etkileri vardır. Ancak kafeinin üreme sağlığına etkisi tartışmalıdır. Bu
derlemede kafein tüketiminin fertilite üzerine etkilerinin değerlendirilmesi
amaçlanmıştır. Pubmed, Web of Science, Cochrane, ve Lilacs elektronik veri
tabanlarında “fertilite”, “infertilite”, “üreme”, “kafein”, “kahve”, “çay”, “kafeinli”
terimleri ile tarama yapılmıştır. gözden kaçırılan çalışmaların olması ihti-
maline karşı ek olarak genel bir tarama yapılmıştır. tarama sonucu toplam
12 çalışma bu derlemeye dahil edilmiştir. Çalışmalardan 5’i kafeinin fertilite
üzerine olumsuz, 2’si olumlu etkileri olduğunu rapor etmektedir. Olumsuz
sonuçlar sunan çalışmalar genellikle kafeinin seks hormonlarına etkisi ve
lüteal fazı kısaltıcı etkilerine yoğunlaşmıştır. Ancak 5 çalışma kafein alımı ve
fertilite arasında herhangi bir ilişki bulmamıştır. Çalışma sonuçları doğrultu-
sunda gebelik planlayan çiftlere kafein alımını azaltmaları tavsiye edilebilir.
Ayrıca bireyler kafeinsiz içecekleri tüketimleri konusunda teşvik edilmelidir.
Anahtar Kelimeler: Kafein, kahve, fertilite, doğurganlık, gebelik
Review /
Cite this article as: Macit MS, Akdevelioğlu Y. An Overview of The Relationship Between Fertility and Caeine Intake. Clin Exp Health Sci 2018; 8: 138-45.
ed levels (<200–300 mg/day), appears to have no serious eects on
reproductive life. It is still advisable to avoid excessive caeine in-
take for women and men who plan to conceive. The recommended
amount for conception is 100–200 mg/day, which is dened as mild
consumption and equivalent to fewer than two cups of coee per
day (12).
This relationship has been explained by several mechanisms in stud-
- There is an inverse correlation between caeine and estradiol in
pregnant woman.
- There is a positive correlation between caeine and sex hor-
mone-binding globulin.
- Caeine may decrease prolactin levels and may inhibit ovula-
- Caeine may aect the transportation of conceptus (4,13–16).
It was stated that the eects of coee may be due to dierent com-
ponents rather than caeine (4). However, it is dicult to distinguish
the eects of coee and caeine due to high correlation in their in-
take (17).
Pregnancy is a natural process and aected by several factors. It is
important to eliminate the possible risk factors for a healthy con-
ception and pregnancy. In terms of nutrition, caeine is one of the
nutrients that is thought to inuence reproductive health. However,
study results are not clear owing to dierent study types and designs.
This review aimed to sum up these study results and to assess the
relationship between caeine intake and fertility, fecundability, and
conception time.
A literature search was conducted using the electronic databases
PubMed, Web of Science, Cochrane, and LILACS. The search terms
“fertility,” “infertility, “fecundability,” “reproductive,” “caeine,” “coee,
“tea,” and “caeinated” were used. The search was performed through
appropriate methods and keywords by using “AND” and “OR.” An ad-
ditional manual search was also performed for missing articles, and
one article was added to the study. Three studies were excluded in
this review owing to no access to full text and abstract (18–20). Out-
comes were determined by birth, fertility, fecundability, fecundabil-
ity rate (FR), and spontaneous abortion. With this regard, this review
is restricted to human studies of caeine and its associated factors
and excluded fetal death, congenital malformations, and gestation-
al age/preterm birth. We have only included spontaneous abortion
outcome that appears after conception.
Articles were viewed according to the following inclusion and exclu-
sion criteria.
Inclusion criteria:
written in English
human studies
clinical trial or randomized controlled design or presenting
cross-sectional or prospective data.
Exclusion criteria:
case studies, reviews, and meta-analyses
animal studies.
Figure 1 shows the selection methodology and number of articles. A
total of 318 articles from PubMed, 274 articles from Web of Science,
33 articles from Cochrane, and 25 articles from LILACS were found.
Articles were screened with a review process according to:
title and abstract
full-text examination.
According to the selection criteria, eight studies with prospective de-
sign, two studies with retrospective design, and three studies with
follow-up were included in this review. Heterogeneity of study de-
signs and study characteristics does not allow to conduct any statis-
tical analyses.
Studies have revealed controversial results for the relationship be-
tween caeine intake and reproductive health. The present review
aimed to review studies evaluating outcomes, fertility, and live births.
According to the literature search, 13 studies were included in this
review. Table 2 shows the study results.
Six studies revealed negative eects of caeine intake on reproduc-
tive health, two of them reported positive eects, and ve studies
found no association. According to studies that were included in
this review, Wilcox et al., Jensen et al., Bolumar et al., Klono-Cohen
et al., Wesselink et al., and Gaskins et al. reported negative eects
of caeine, coee, or tea intake on reproductive health parameters
(2,4,8,21–23). Hatch et al. and Florack et al. reported a positive rela-
tionship (24,25). However, Hakim et al., Taylor et al., Chavarno et al.,
Curtis et al., and Caan et al. found no association (26–30).
First, studies that found a negative association of caeine determined
the FRs as an outcome. Wilcox et al. conducted the rst study that
reported a negative association between caeine and fecundability.
They found 50% lower FRs in the group who consumed high amounts
of caeine (21). Jensen et al. found that more than 700 mg/day caeine
Clin Exp Health Sci 2018; 8: 138-45 Macit et al. Fertility and Caeine Intake
Table 1. Amount of caeine in some foods and beverages.
Foods and beverages Caeine content (mg)
Filter coee (200 mL) 90
Espresso (60 mL) 80
Black tea (220 mL) 50
Green tea (220 mL) 24
Coke (335 mL) 40
Plain chocolate (50 g) 50
Milk chocolate (50 g) 10
Standard energy drink (250 mL) 80
United States Department of Agriculture, Agricultural Research Service, USDA
Food Composition Databases. Available from:
search/list (5).
European Food Safety Authority. Available from:
default/les/corporate_publications/les/efsaexplainscaeine150527.pdf (6).
intake is associated with reduced fecundability among non-smokers
(men, OR: 0.47, 95% CI: 0.26–0.82 and female, OR: 0.63, 95% CI: 0.25–
1.60) (2). They reported the eect of caeine with reduced clearance
during the luteal phase and accumulation in implantation. Among
smokers, fecundability was decreased when caeine intake was more
than 300 mg/day among non-smokers (OR: 0.74, 95% CI: 0.59–0.92)
(20). It was stated that smokers may consume more caeinated bev-
erages, and smoking also enhances the metabolism of caeine via the
induction of hepatic cytochrome P-450 enzymes and increases N-de-
methylation (27). Caeine is the rst-choice substrate for CYP1A2 and
is often used for phenotyping of human cytochrome P450 (31,32).
Smoking also increases the metabolism of xanthine oxidase activity
and caeine (4). Bolumar et al. also reported that a 501 mg/day caf-
feine intake is associated with subfecundity (OR: 1.03–2.04, 95% CI:
1.45). Contradictory to these results, the association was stronger in
smokers. They explained this dierence in previous studies that heavy
coee drinkers smoke more (4).
Gaskins et al. examined the Nurses’ Health Study II (1991–2009) co-
hort and reported the eects of caeine consumption (23). When
caeine intake was categorized, there was a positive linear trend
across categories of pre-pregnancy caeine intake and risk of sponta-
neous abortion such that women consuming >400 mg/day had 1.11
(95% CI: 0.98–1.25) times the risk of spontaneous abortion compared
Clin Exp Health Sci 2018; 8: 138-45Macit et al. Fertility and Caeine Intake
Figure 1. Selection methodologhy of articles
Clin Exp Health Sci 2018; 8: 138-45 Macit et al. Fertility and Caeine Intake
Table 2. Overview of studies.
Studies Year Sample Study design Method Country Outcome
ment Inclusion Exclusion Results
Hakim et
al. (26)
1998 124
Steroid hormones and human
chorionic gonadotropin assess-
ment (urine), caeine intake (food
frequency for the last 1 month),
caeine content for coee: 100
mg, tea: 40 mg, cola: 50 mg
Caeine intake classication:
0–25 mg, 26–100 mg, 101–300
≥301 mg
America Probability
of concep-
tion per 100
alcohol, age,
with repro-
Using oral
tive and
Caeine (mg/day) n
Birth/no. of menstru-
0–25 30 39/196 (19.9)
26–100 32 26/184
101–300 53 28/258
≥300 9 6/40 (15.0)
et al. (2)
1998 430
(3 years)
Follow-up for 6 menstruation
cycles or until conception
Intercourse frequency, reproduc-
tive health, vaginal bleeding
Semen sample
Caeine intake: daily or weekly
Caeine content
1 cup of coee: 100 mg,
1 cup of tea: 50 mg, 1 cup of
chocolate beverage: 25 mg, 0.25 L
cola: 100 mg, 50 g chocolate bar:
12.5 mg
Caeine classication:
0–299 mg, 300–699 mg, >700 mg
Denmark Each cycle
or not
BMI and
diseases of
the female
tive organs,
quality, and
of the
Not having
a child
before, not
using birth
Among non-smokers,
intake of more than 700
Caeine was associated
with an FR of 0.63
(95% CI:
0.25–1.60) among
females and 0.47 (95%
CI: 0.26–0.82) males
et al. (4)
1997 3187
Retrospective Conception time, caeinated
beverage consumption
Caeine content:
Tea: 40 mg, cola: 50 mg,
coee: 130 mg for Denmark, 115
mg for South Europe, 115 mg for
Germany (according to coee
type, size of cup, and brewing
Caeine classication:
0–100, 101–300, 301–
500, and ≥501 mg
Conception time: 0–3.4, 3.5–9.4,
9.5–15.4 and >15.5
Age (20,
31 years),
smoking for
the last 12
≥501 mg caeine in-
take is associated with
(OR: 1.03–2.04,
95% CI: 1.45)
Curtis et
al. (29)
1997 2607
cies <44
Daily coee, tea, and cola con-
Caeine content for coee: 100
mg, tea: 40 mg, cola: 50 mg
Canada ––Planned
Using oral
tive, trying
to become
more than 1
There was no relation-
ship between caeine
intake and fertility
(<100 mg and >100
mg). Coee intake in
women and tea intake
in men were associated
with FR (0.92, 95% CI:
0.84–1.00 and 0.85,
95% CI: 0.69–1.05,
et al. (30)
1998 187
Follow-up Food frequency (last 1 month) America Age, BMI,
frequency of
and alcohol-
ic beverages
planning for
There was no relation-
ship between caeine
intake and fertility.
However, an increase
in tea intake caused a
decreased in getting
pregnant (OR: 7.25,
95% CI: 3.06–17.17)
Cohen et
al. (22)
2002 221
(M =
F = 26–49
Prospective Daily coee (100 mg), tea (50 mg),
and cola (50 mg) consumption
Caeine intake: 0–2 mg, 2–50 mg,
50–200 mg, >200 mg
America Oocyte
abortus, live
alcohol, age,
of embryo
with in vitro
or gamete
an transfer
There was no
association between
outcomes and caeine
intake during the study.
However, lifetime
caeine intake was a
risk factor (2–50 mg
and >50 mg) (OR:
3.1–3.9). In men, 100
mg increase in caeine
consumption increased
the risk for multiple
Clin Exp Health Sci 2018; 8: 138-45Macit et al. Fertility and Caeine Intake
Table 2. Overview of studies.
Studies Year Sample Study design Method Country Outcome
ment Inclusion Exclusion Results
et al. (24)
2012 3628
Caeine intake was assessed
at baseline and every 8 weeks
(coee, soda, tea, green tea)
Denmark Fecund-
Age, BMI,
tea, coee
with a
not using
oral con-
(less than 12
Increase FR in women
who consumed
more than >300 mg
compared with <100
mg (FR = 1.04, 95% CI:
0.90–1.21). There was
an inverse association
with soda intake (0.89,
0.80–0.98; 0.85, 0.71–
1.02; 0.84, 0.57–1.25;
0.48 0.21–1.13)
et al. (25)
1994 259
Smoking habits, alcohol
consumption, and caeine
intake (e.g., coee, tea, and cola
consumption) were evaluated
Holland Fecund-
cal hospital
Participants with a
moderate caeine
intake (400–700 mg/
day) showed a higher
fecundability than
those with a lower in-
take level (adjusted OR:
2.1, 95% CI: 1.2–3.7).
Heavy caeine intake
(>700 mg/day) among
partners was negatively
related to fecundability
when compared with
the lowest intake level
(adjusted OR: 0.6, 95%
CI: 0.3–0.97)
Wilcox et
al. (21)
1988 104
Follow-up Caeine intake:
coee: 100 mg, instant coee: 65
mg, tea: 50 mg, soft drinks: 40 mg
USA Fecund-
Age, fre-
quency of
age at
to mother’s
who were
to become
Lower FR in the group
who consumed high
amounts of caeine
et al. (23)
2016 15,590
Dietary intake: a 131-item Food
Caeinated coee: 137 mg
tea: 47 mg caeine/cup, caeinat-
ed sodas: 46 mg caeine/
bottle or can, and chocolate: 7 mg
Study II)
There is a positive
association between
caeine intake
and spontaneous
abortion that women
consuming >400 mg/
day had 1.11 (95% CI:
0.98–1.25) times the
risk compared with
women consuming
<50 mg/day (p<0.05)
et al. (28)
2009 18,555
cohort (Nurses’
Health Study
II), follow-up (8
Food frequency (2 times),
ovulatory disorder, infertility
America Fertility Age,
total energy
with dia-
438 ovulatory
disorder infertilities
were assessed after
follow-up. There was
no relationship with
caeine intake
Taylor et
al. (27)
2011 319
Prospective Daily caeine intake
1 cup of coee: 150 mg,
1 cup of tea: 55 mg,
1 cup of cola: 45 mg
Caeine classication:
<150 mg, 150–300 mg, >300 mg
America Fecund-
Age, BMI,
with N-acet-
2 polymor-
phisms (161
slow, 158
fast acetyla-
device, in-
fertility (not
having a
more than
1 year), hys-
ovary, tube
There was no relation-
ship between caeine
and FR
with women consuming <50 mg/day (p=0.05). Interestingly, when
beverages were evaluated separately, both caeinated and decaf-
feinated coee intakes had a positive association with spontaneous
abortion (p=0.01 and 0.04, respectively). These results need to be
taken into consideration, and further studies should be conducted
on non-caeinated beverages. The possible mechanism associated
with pre-pregnancy coee intake and risk of spontaneous abortion
was explained by the eects of coee on endogenous sex hormone
metabolism, pregnanediol-3-glucuronide levels, lower total and free
luteal plasma estradiol levels, and higher 2-catechol estrogen metab-
olites, 2-hydroxyestrone, and 2-hydroxyestradiol (23).
Klono-Cohen et al. stated that there is no association between caf-
feine and fertilization (22). However, lifetime caeine consumption
was a risk factor for no birth. The possible mechanisms were ex-
plained with the reduced levels of reproductive hormones such as
estradiol. In a recent study, Wesselink et al. found a negative associa-
tion between caeine and fecundability in males but not in females
(8). According to the results of their study, ≥300 mg/day caeine con-
sumption was associated with decreased fecundability among males
(M = 0.72, 95% CI: 0.54–0.96). It was emphasized that low caeine
intake of cohort may weaken the associations. Hatch et al. also re-
ported that there is a minor negative eect of caeine on reproduc-
tive systems for participants who consumed more than 300 mg/day
caeine (24). They claimed that this association may be stronger in
less fertile women.
Hakim et al. found no relationship with daily coee intake on births
(26). However, they found a decrease in the probability of concep-
tion that consumed alcohol and claimed that caeine may worsen
the eects of alcohol. Separate analyses were also conducted on
participants who did not consume alcohol or cigarette. It was stat-
ed that there is also a decrease, though not statistically signicant,
conception rate in women who consumed more than one cup of
coee (18.0%, adjusted OR: 0.56). Hakim et al. also reported that the
association may occur even in low intakes than previous studies sug-
gested for more than three cups of intakes (26). Similar to their study,
Curtis et al. found no association between caeine and fertility (29).
However, they reported that fecundability is decreased in females
who consumed coee and in males who consumed tea (0.92, 95%
CI: 0.84–1.00 and 0.85, 95% CI: 0.69–1.05, respectively). These results
that were explained with the possibility of bias by misclassication
of caeine exposure were consistent with the literature that found
reduced FRs.
Caan et al. also could not nd any statistically signicant decrease in
fertility in terms of caeine intake (30). Their study was conducted on
187 participants; it was a small sample size compared with the stud-
ies with large cohorts (4,27). The aim of their study was to prevent
bias in which retrospective studies might involve and assess odds ra-
tios with an 80% power. This power ratio may still be not enough to
detect the relationship.
Chavarro et al. conducted a study with a large cohort (Nurses’ Health
Study II), with 18,555 women with a long follow-up (8 years) (28).
After the follow-up period, 438 ovulatory disorder infertilities were
reported but no positive association between the intake of caeine,
coee, tea, or decaeinated coee and risk of ovulatory infertility.
They emphasized the lack of methodological design of retrospective
studies, which Leviton and Cowan discussed in detail in their study
(32). Taylor et al. (27) evaluated the eects of caeine with a similar
design but smaller sample size compared with Chavarro et al. (28).
Their study conducted on women who had N-acetyltransferase 2
(NAT2) polymorphisms also failed to nd an association; however,
the relationship was assessed regardless of NAT2 acetylation status.
In this review, caeine consumption was evaluated in terms of
pre-pregnancy. In pregnancy, caeine intake should also be consid-
ered. Buck Louis et al. reported that more than two daily caeinated
drinks are signicantly associated with pregnancy loss (preconcep-
tion [aHR 1/4 1.74, 1.07–2.81], early pregnancy [aHR 1/4 3.05, 1.75–
5.34], and periconception [aHR 1/4 2.58, 1.56–4.27]) (33). Their study
provides a dierent perspective on the ow of the present review
and supports the idea to decrease caeine consumption after preg-
nancy especially in the rst trimester in which Gaskins et al. reported
higher rates of spontaneous abortion (23).
When we evaluate the studies on caeine in terms of consumption
amounts (mg), the negative eect of caeine on reproductive health
ranges between 300 and 700 mg/day. However, taking into consid-
eration coee consumption, this amount decreases to 100 mg/day.
Even if 200 mg/day caeine intake is determined as a maximum in-
take for pregnant women, the eect of coee at 100 mg/day intake
supports the idea to decrease the consumption as much as possible.
There are several studies about caeine consumption and repro-
ductive health. However, dierent designs make it more dicult to
Clin Exp Health Sci 2018; 8: 138-45 Macit et al. Fertility and Caeine Intake
Table 2. Overview of studies.
Studies Year Sample Study design Method Country Outcome
ment Inclusion Exclusion Results
selink et
al. (8)
2016 2135
Daily consumption of beverages
(coee: 135 mg, decaeinated
coee: 5.6 mg, black tea: 20 mg,
green tea: 20 mg, white tea: 15
mg, soda: 23–69 mg, energy
drink: 48–280 mg)
Age, eth-
nicity, BMI,
stress, sleep,
to increase
21–45 years,
not using
not having
There was no asso-
ciation for women;
however, an increase
in caeine intake was
related with a decrease
in FR (FR ≥300 vs. <100
mg/day = 0.72, 95% CI:
BMI, body mass index.
compare results. Some of the studies focus on caeine consumption,
whereas some of them focus only on coee consumption owing
to its high caeine content. Focusing on coee intake alone would
probably result in underestimations of total caeine intake. Accord-
ing to dierent countries, caeine intake might dier, and chocolate,
black tea, or green tea may become an important source of caeine.
Additionally, coee consumption is evaluated as “one cup of coee
or “one serving”. Nevertheless, type of coee beans, brand, roasting
degree (soft, medium, and dark roasted), infusion time, and cup size
aect coee content. These covariates should be considered in study
designs. In addition, retrospective studies tend to show more rela-
tionship between caeine intake and fertility which may be a result
of asseseing caeine intake with retrospective questionnaire. After
analyzing the study designs, it becomes dicult to give a clear rec-
ommendation, but if these study results are considered, it may be
advisable for couples who are planning to conceive to decrease caf-
feine intake as much as possible, especially from coee. There are
also other caeine sources, but coee is the main source of caeine
in the diet. It may also be recommended to consume other sources of
healthy beverages and foods if there is a need. Further studies with a
detailed design and accurate measurement of caeine intake should
be conducted to clarify the eects of caeine including decaeinat-
ed beverages.
The selected studies dier in quality of information, study design,
and categorization of caeine exposure. These study limitations af-
fect the present study and make it dicult to present an extensive
recommendation. Nevertheless, these limitations reveal the need for
an accurate assessment of caeine intake. Individual assessment of
dietary intake may be useful instead of standard questionnaires.
Peer-review: Externally peer-reviewed.
Author contributions: Concept – M.S.M, Y.A.; Design - M.S.M, Y.A.; Supervi-
sion - Y.A.; Resource M.S.M.; Materials - M.S.M.; Data Collection and/or Process-
ing - M.S.M.; Analysis and/or Interpretation - M.S.M.; Literature Search - M.S.M.;
Writing - M.S.M., Y.A.; Critical Reviews - M.S.M., Y.A.
Conict of Interest: The authors have no conict of interest to declare.
Financial Disclosure: The authors declared that this study has received no
nancial support.
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Full-text available
Infertility is a multi-causal, multivariate disease with an increasing rate all over the world. Couples who cannot have children normally apply to some treatments using assisted reproductive techniques and in vitro fertilization centers. It is possible to pay for the treatment by the state. But there are various conditions for it to be paid by the government and compared to the private sector, time, comfort etc. are differences in aspects. For these reasons, it is observed that consumers generally prefer private sector organizations by forcing their conditions. The subject of this research is to determine the profile differences of consumers who receive infertility treatment through in vitro fertilization centers in Turkey. The purpose of this research is to determine the factors that shape the purchasing preferences and consumer profiles of consumers who have received health services from IVF centers. For this purpose, data were collected from 268 consumers who received successful or unsuccessful infertility treatment through in vitro fertilization centers in Turkey in the last 15 years. The obtained data were analyzed with the SPSS program. It has been tried to determine the variables that lead the consumers to the preference of IVF center and create profile differences in terms of trust, preference and repetitive purchasing. Factor analysis was used to classify the determined variables and 8 factors were obtained. These factors are; IMC-promotion, IMC-pricing, eWOM-information search, WOM, eWOM/WOM-advice, patient-physician communication, service design-equipment and service design-employees factors. Consumers were segmented using the variables obtained as a result of factor analysis. In the segmentation part, cluster analysis was used. The differences of the four clusters obtained were determined by one-way analysis of variance and it was seen that the clusters had significant differences from each other. As a result of the analyses, the first cluster was named as “fans”, the second cluster as “perfectly satisfied”, the third cluster as “managers” and the fourth cluster as “fastidious” and cluster differences were evaluated in detail. Finally, recommendations have been developed for practitioners and further studies.
Background: One in seven couples are impacted by infertility in the UK, and female infertility is often associated with several health conditions impacted by nutrition. Despite many studies aimed at identifying the critical role of nutrition in infertility, there is currently no screening tool that identifies nutritional risk factors for infertility. Aim: To propose a self-administered screening tool to identify women who would benefit from nutritional intervention to promote fertility. Methods: A narrative review was carried out to identify and summarise modifiable nutritional risk factors that can influence female fertility, including comorbidities that can influence nutrition intake, absorption, and metabolism. Key findings: A nutrition screening tool outlining modifiable nutrition risk factors potentially improving female fertility has been proposed, comprising of BMI, medical history and quality of diet and lifestyle which would aid in designing evidence based dietetic services for female infertility.
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PurposeTo investigate the relation between pre-pregnancy caffeine and caffeinated beverage intake and risk of spontaneous abortion (SAB). Methods Our prospective cohort study included 15,590 pregnancies from 11,072 women with no history of SAB in the Nurses’ Health Study II (1991–2009). Beverage intake was assessed every 4 years using a validated questionnaire. Pregnancies were self-reported with case pregnancies lost spontaneously at <20 weeks gestation. Multivariable log-binomial regression models with generalized estimating equations were used to estimate the relative risks (RRs) and 95 % confidence intervals (CIs). ResultsThere was a positive linear trend across categories of pre-pregnancy caffeine intake and risk of SAB such that women consuming >400 mg/day had 1.11 (95 % CI 0.98, 1.25) times the risk of SAB compared to women consuming <50 mg/day (p trend = 0.05). Total coffee intake had a positive, linear association with SAB. Compared to women with no pre-pregnancy coffee intake, women consuming ≥4 servings/day had a 20 % (6, 36 %) increased risk of SAB (p trend = 0.01). There was no difference in the association between caffeinated and decaffeinated coffee and risk of SAB. Pre-pregnancy intake of caffeinated tea, caffeinated soda, and decaffeinated soda had no association with SAB. Conclusions Pre-pregnancy coffee consumption at levels ≥4 servings/day is associated with increased risk of SAB, particularly at weeks 8–19.
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Background Previous studies showed that high dose of caffeine intake may induce some specific human reproductive system diseases, even lead to infertility. Objectives In consideration of the high consumption of caffeine according to the latest population-based survey, this review is aimed to systematically review the evidence from all controlled clinical studies of caffeine intake for infertility. DesignsRelevant randomized/quasi-randomized controlled trials, non-randomized clinical studies, cohort studies, and case-control studies will be included in this review. Participants will be either those without a history of infertility who are willing to have a baby (for prospective studies) or infertile patients with confirmed diagnosis (for retrospective studies). Caffeine or caffeine-containing beverage will be observed as the exposure factor. The key outcome will be the diagnosis of infertility in participants. All relevant published/unpublished or ongoing studies will be searched from seven databases and four online systems until December 2015. Two authors will screen the literatures and extract the data independently. Methodological quality of the included studies will be assessed by two authors according to either Risk of Bias Assessment or Newcastle-Ottawa Scale. We will use R software to analyze the data. Dose of caffeine will be quantified on a daily basis, and relative risk with their 95 % confidence interval will be measured. If data permit, meta-analysis and dose-response analysis will be conducted. Summary of findings tables will be generated using Guideline Development Tool online. Systematic review registrationPROSPERO CRD42015015714
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The reproductive cycle in women is complex and can be considered to begin with epigenetic programming and ending with menopause. Intervening steps involve a variety of processes, including the cellular development of the sex organs, menarche, episodic endocrine cycles, menstruation, ovulation and conception. These processes can be influenced by diet and nutrition and vice versa. Body composition has an impact on the menstrual cycle and periconception and these factors in turn also influence body composition. Similarly, either food deprivation, dietary excess or obesity can result in marked changes in the menstrual cycle with a concomitant effect on fertility. This handbook is the first scientific source that provides a comprehensive overview of the relationship of diet and nutrition with puberty, menarche and menstrual cycle, conception and fertility and infertility. The handbook of diet and nutrition in the menstrual cycle, conception and fertility will benefit dieticians, nutritionists, gynaecologists, endocrinologists, obstetricians, paediatricians and those concerned with women's health in general.
The relationships between concentrations of endogenous hormones in serum and dietary intakes of alcohol, fats, fiber, and caffeine were examined in 325 healthy Massachusetts women aged 50–60 y who reported having a normal menstrual period within the previous 12 mo. Diet was assessed by a semiquantitative food frequency questionnaire. Hormones assayed were estrone, estradiol, percent free estradiol, sex-hormone-binding globulin (SHBG), Cortisol, and gonadotropins. Alcohol intake was not associated with concentrations of estrogens or gonadotropins. Neither total fat intake nor the fat composition of the diet influenced hormone concentrations. Fiber intake was positively correlated with SHBG; no associations with estrogens were seen. Caffeine intake was inversely correlated with free estradiol and positively correlated with SHBG. These data suggest that fat, fiber, and alcohol intakes of US women at climacteric are not determinants of variations in estrone and either total or percent free estradiol.
Reproduction in the female requires a complex sequence of integrated events including ovulation, gamete transport, fertilization, concept us transport, implantation, fetal support, and finally parturition. Each of these individual reproductive events represents the sum of many systemic, local, cellular, and molecular interactions. All of these processes have varying degrees of susceptibility to interference by xenobiotic compounds. This chapter presents a brief review of some of these mechanisms or female reproductive biology.
Caffeine is an adenosine receptor antagonist that may influence fertility by affecting ovulation, menstrual characteristics, or sperm quality. We studied the association between female and male preconception caffeine intake and fecundability in a North American prospective cohort study of 2,135 pregnancy planners. Frequency of caffeinated beverage intake was self-reported at baseline. Outcome data were updated every 8 weeks until reported pregnancy; censoring occurred at 12 months. Adjusted fecundability ratios (FR) and 95% confidence intervals (CI) were estimated using proportional probabilities regression. Total caffeine intake among males, but not females, was associated with fecundability (FR for ≥300 vs.<100mg/day caffeine among males=0.72, 95% CI=0.54-0.96), although the association was not monotonic. With respect to individual beverages, caffeinated tea intake was associated with slight reductions in fecundability among females, and caffeinated soda and energy drink intake were associated with reduced fecundability among males.
Objective: To estimate pregnancy loss incidence in a contemporary cohort of couples whose lifestyles were measured during sensitive windows of reproduction to identify factors associated with pregnancy loss for the continual refinement of preconception guidance. Design: Prospective cohort with preconception enrollment. Setting: Sixteen counties in Michigan and Texas. Patient(s): Three hundred forty-four couples with a singleton pregnancy followed daily through 7 postconception weeks of gestation. Intervention(s): None. Couples daily recorded use of cigarettes, caffeinated and alcoholic beverages, and multivitamins. Women used fertility for ovulation detection and digital pregnancy tests. Pregnancy loss was denoted by conversion to a negative pregnancy test, onset of menses, or clinical confirmation depending upon gestation. Using proportional hazards regression and accounting for right censoring, we estimated adjusted hazard ratios and 95% confidence intervals (aHR, 95% CI) for couples' lifestyles (cigarette smoking, alcoholic and caffeinated drinks, multivitamins) during three sensitive windows: preconception, early pregnancy, and periconception. Main outcome measure(s): Incidence and risk factors for pregnancy loss. Result(s): Ninety-eight of 344 (28%) women with a singleton pregnancy experienced an observed pregnancy loss. In the preconception window, loss was associated with female age ≥35 years (1.96, 1.13-3.38) accounting for couples' ages, women's and men's consumption of >2 daily caffeinated beverages (1.74, 1.07-2.81; and 1.73, 1.10-2.72, respectively), and women's vitamin adherence (0.45, 0.25-0.80). The findings were similar for lifestyle during the early pregnancy and periconception windows. Conclusion(s): Couples' preconception lifestyle factors were associated with pregnancy loss, although women's multivitamin adherence dramatically reduced risk. The findings support continual refinement and implementation of preconception guidance.
Handbook of Fertility: Nutrition, Diet, Lifestyle and Reproductive Health focuses on the ways in which food, dietary supplements, and toxic agents, including alcohol and nicotine affect the reproductive health of both women and men. Researchers in nutrition, diet, epidemiology, and endocrinology will find this comprehensive resource invaluable in their long-term goal of understanding and improving reproductive health. This book brings together a broad range of experts researching the different aspects of foods and dietary supplements that promote or detract from reproductive health. Section One contains several overview chapters on fertility, how it is assessed, and how it can be affected by different metabolic states, nutritional habits, dietary supplements, the action of antioxidants, and lifestyle choices. Sections Two and Three consider how male and female fertility are affected by obesity, metabolic syndrome, hormonal imbalance, and even bariatric surgery. Section Four explores the ways diet, nutrition, and lifestyle support or retard the success of in vitro fertilization, while Section Five explores how alcohol and other drugs of abuse lower fertility in both women and men.