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Conception Pregnancy Apr 15, 2019
6 Minutes

If you like coffee – this may surprise you…

This article details the impact of caffeine on conception and during pregnancy. Should you avoid it/is it ok to drink when you’re trying for a baby? It also looks at the guidelines around caffeine during pregnancy, what the latest science suggests particularly around the link between caffeine and miscarriage.

I don’t know about you, but I have been pretty confused when it comes to coffee. Is it good for you? Is it not good for you? Every day there seems to be a different study coming out arguing one thing or another. Should you avoid it altogether or is a cup or two ok or even beneficial?!

The main question is really around caffeine, a pretty powerful substance which seems to have varying effects depending on the stage of life you are in and how much you’re drinking.

Given its potency (and how much as a society we tend to drink it) when it comes to our purposes: trying to conceive and grow healthy babies, there is quite a bit of research ongoing – here is what you need to know:

Firstly: How much is ‘ok’ to drink is highly dependent on whether you are trying to conceive, or, are already pregnant – and boys –  this means you too…

The two most important takeaways from the latest research are this:

ONE: if you are trying to conceive, and particularly if you have PCOS or very long cycles, drinking it in moderation can actually potentially be helpful (yeah…I was surprised too!).

TWO: if you are already pregnant, the guidelines published by the WHO (World Health Organisation) who state that no more than 300mg (approx 3 cups/day) and the EFSA (European Food Safety Authority) who state no more than 200mg (approx 2 cups) is ok to consume – may even be too high and in fact, it seems that you should drink less than that and ideally none at all.

Here’s the detail:

Let’s take a step back and understand the effect caffeine has on the body:

Caffeine of course is found in more than just coffee. It is also in tea, soft drinks and even chocolate. It has two main metabolites: Paraxanthine and Theobromine. To give an example: Coffee has much more paraxanthine than tea and chocolate which have more Theobromine so the source does impact it to an extent. (1)

As a substance, Caffeine is rapidly distributed throughout the body and has been found in saliva, breastmilk, the embryo and even the neonate, which just goes to show how powerful it is. The caffeine molecule ‘is easily absorbed by humans, having approximately 100% of bioavailability, when taken by oral route and reaching a peak within the blood within 15-45 minutes after its consumption.’ (3)

It has been shown to:

  • Stimulate the Central Nervous System

  • Increase secretion of a key neurotransmitter Catecholamine (including Adrenaline and Dopamine)

  • Relax smooth muscles

  • Stimulate heart rate

It also has quite meaningful effects on our hormones….

Studies have shown an impact on a range of things from testosterone, cortisol, estrogen and the HPGS (hypothalamus-gonadal-system) so of course when it comes to getting and staying pregnant (a time where hormones are even more important than usual) it matters. This is where it gets more interesting:

What happens if I am trying to get pregnant?

One of the more interesting bits of recent research has focused upon the impact of caffeine on testosterone. As a reminder, this is not just a hormone that men have, in fact, when it is out of balance in women it can be a signal of Polycystic Ovarian Syndrome (PCOS) which is one of the main causes of infertility and is often undiagnosed ie. you may not know that you are even affected.. Click here for more.

One of the common features of PCOS is testosterone being higher than it should be which causes many symptoms, but specifically can cause issues with ovulation (ie. eggs not being released: anovulation) which of course makes getting pregnant a bit tricky!

A few studies have shown that for women, caffeine in moderation can in fact help control some of the imbalance and even help promote ovulation:

‘We showed that serum concentrations of caffeine and paraxanthine were significantly associated with lower total testosterone, free testosterone, and LH concentrations (also usually higher in PCOS patients) and lower risk of anovulatory episodes…which suggested that moderate caffeine intake may be associated with increased menstrual cycle function.’ N.b. Moderate in the context of this study was no more than two/three cups/day (1)

Translation: if you have PCOS/higher than normal levels of testosterone which can cause issues with ovulation then caffeine has been shown to help control this.

Another study of nearly 20,000 women over 8 years linked caffeine to increased insulin sensitivity which is another issue that PCOS patients can sometimes struggle with:

‘Caffeine intake has been linked to increased insulin sensitivity, which in turn has been related to increased ovulatory function in women with PCOS. PCOS is the most common cause of anovulation (failure to ovulate) in women of reproductive age, and the most common cause of infertility due to ovulation disorders.’ (2)

There was even an observation between this and the incidence of twins!

‘Furthermore, a positive association between pre pregnancy coffee drinking and a higher rate of dizygotic twin pregnancies has been described, suggesting that caffeine may, if anything, stimulate ovulation rather than suppress it.’

However: one important caveat:

There is a caveat here and it relates to caffeinated soft drinks which were shown to have the reverse effect, similarly affecting men also:

‘Soft drinks were the only beverages positively correlated to ovulatory infertility.’ With Wilcox and colleagues reporting that an increase of one caffeinated soft drink per day was associated with a 50% lower chance of conception each month after accounting for coffee consumption and other relevant variables. (2)

On many levels soft drinks and particularly caffeinated ones (like energy drinks) should be avoided – here is another one.

What about the boys?

We know that sperm counts, motility etc are on the decline in the Western world – click here for more – but the good news here is that caffeine on the whole does not (in moderation) seem to have any negative effects. Once again – soft drinks were the exception:

‘Semen parameters did not see affected by caffeine intake, at least caffeine from coffee, tea and coca drinks in most studies. Conversely, other contributions suggest a negative effect of cola-containing beverages and caffeine containing soft drinks on semen volume, count and concentration’ (3)

Key takeaway: If you are trying to get pregnant there appears no harm in moderate caffeine intake as long as it is not from a soft-drink. In fact, if you have PCOS moderate caffeine intake may even be a good thing. Of course we all react differently so always listen to your body.

Moderation is of course the key thing here, particularly as too much caffeine has been shown to activate the stress axis within the body, acting to increase cortisol secretion by elevating production of ACTH at the pituitary. (5). If we know one thing about conception it is that if the body deems it is under threat (too much cortisol) then it will not dedicate the energy to allowing conception to take place. Click here for more on this.

So, what about if I think I may be pregnant or am pregnant?

Now this is a very different story. Research has been consistently suggesting that caffeine could play a role in miscarriage which is why organisations like the WHO and EFSA suggest limits on how much you should drink if you are pregnant. We also know that caffeine does get into the placenta and even into the foetus:

‘In pregnant women, caffeine readily crosses the placental barrier and as a result is distributed to all fetal tissue, making the foetus exposed to the same caffeine levels as the mother.’ (4)

Now the mechanism behind how this works is not entirely clear, although there is some suggestion of an impact on placental blood flow, however several studies support an ‘increased risk of experiencing a spontaneous abortion (SAB) with increased coffee/caffeine during early pregnancy’ and ‘recently, a meta-analysis reported than an increment intake of 100mg (ie. one cup) caffeine/day was associated with a 14% higher risk of SAB.’ (4) which is why even having two cups a day may not be such a great idea.

Key takeaway: if you are pregnant why risk it? Yes, it can be a hard habit to break, however there are lots of other options these days for drinks that don’t contain caffeine and it is only a few months of your life. Going cold turkey can be hard, particularly as for a lot of us our cups of coffee are also based on habit, so instead finding a substitute can be helpful and experimenting with lots of different options until you find the drink that is right for you.

See below a quick sources of caffeine table (credit: that may be helpful if you’re trying to avoid!


  1. SCHLIEP K, SCHISTERMAN E, MUMFORD S: Serum caffeine and paraxanthine concentrations and menstrual cycle function: correlations with beverage intakes and associations with race, reproductive hormones, and anovulation in the BioCycle Study: The American Journal of Clinical Nutrition: 2016: JulL 104(1): 155-163

  2. CHAVARRO J.E., RICH-EDWARDS JW, WILLETT W: Caffeinated and alcoholic beverage intake in relation to ovulatory disorder infertility. Epidemiology: 2009 May: 20(3): 374-381

  3. RICCI E, VIGANO P, PARAZZINI F: Coffee and caffeine intake and male infertility: a systematic review: Nutrition Journal: 2017: 16:37

  4. LYNGSO J, RAMLAU-HANSEN CH, KESMODEL US: Association between coffee or caffeine consumption and fecundity and fertility: a systematic review and dose-response meta-analysis: Clinical Epidemiology: 2017: 9: 699-719

  5. LOVALLO WR, WHITSETT TL, WILSON MF: Caffeine Stimulation of Cortisol Secretion across the Waking Hours in Relation to Caffeine intake levels: Psychosomatic Medicine: 2005: 67(5):734-739


This article is for informational purposes only. This article is not, nor is it intended to be, a substitute for professional medical advice, diagnosis, or treatment and should never be relied upon for specific medical advice. The information on this website has been developed following years of personal research and from referenced and sourced medical research. Before making any changes we strongly recommend you consult a healthcare professional before you begin.

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