Caffeine is the most popular and widely used drug worldwide.  Let’s see whether it gets a thumbs up or thumbs down in the literature…

Messes with your (and your offspring’s) fertility

  • Maternal caffeine consumption impairs gonad (sex organ) development, and has long-term adverse effects on the reproductive efficiency of male offspring (… in rats);
  • For females, one of the most common exposures associated with decrease fertility (in humans this time!) is caffeine intake of more than 250mg daily;
  • In one study, women who abstained from alcohol and consumed less than one cup of coffee or its equivalent per day conceived 26.9 pregnancies per 100 menstrual cycles compared with 10.5 per 100 menstrual cycles among those who consumed any alcohol and more than one cup of coffee per day (with this finding it’s a bit hard to tease apart the effects of alcohol vs caffeine);
  • High caffeine intake may delay conception among fertile women (high being defined here as >500mg caffeine daily);
  • For those of you considering the IVF route, it has been found that increased coffee consumption is associated with an increased number of aborted pregnancies, and that the number of good embryos decreases with high tea consumption.

Bottom line: excessive caffeine not great for fertility.

Affects your baby’s growth & development

  • Caffeine intake during pregnancy is associated with decreased birth weight and increased odds of the baby being small-for-gestational-age;
  • There are also concerns regarding whether caffeine intake during pregnancy will result in ‘problem’ children. One study carried with over 8000 women found that there was no evidence that intrauterine exposure to caffeine resulted in behaviour problems in their children (this study looked at children once they reached primary school age);
  • Caffeine is also known to have a negative effect on bones. It has been shown that softer bones are produced when animal foetuses are exposed to caffeine;
  • Caffeine has also been shown to be associated with insulin resistance (and therefore diabetes).

Bottom line: excessive caffeine is not great for the baby.

Caffeine and breastfeeding

  • Caffeine is a cariogenic agent when newborns are exposed to it (ie. it is a threat to healthy tooth development);
  • Another animal study (poor rats!) found that caffeine exposure during lactation produced rats that had decreased motor activity and reduced interaction with the environment;
  • Animals exposed to caffeine in breast milk have also been found to have impaired bone growth and development; this effect is persistent even after changing the young animal back to a caffeine-free diet for an extended time after weaning.

Bottom line: excessive caffeine intake is not ideal when you’re breast-feeding.

(I think we’re seeing a pattern…)

Don’t start freaking out yet if you’re still enjoying your daily coffee while pregnant or breast-feeding… A lot of the above studies are carried out in animals (and while they have implications for humans, sometimes the findings are not always directly applicable to us).

Maybe the current guidelines will give us more information regarding caffeine intake during pregnancy and breast feeding…

  • World Health Organisation (  recommends no more than 300mg caffeine per day (for both pregnancy and breast-feeding).   Risks: maternal caffeine passes through breast milk and may cause hyperactivity and sleeping problems in the baby;
  • Australian Government recommendations are even more conservative at 200mg per day.

If you’re wondering how many ‘mg’ your daily cuppa is worth:

  • Chocolate drinks – 30 to 60 mg;
  • Instant coffee – 60 to 100 mg;
    Drip or percolated coffee – 100 to 150 mg;
  • Espresso coffees such as espresso or latte – 90 to 200 mg;
  • Cola drinks – 35 mg;
  • Decaffeinated coffee – around 3 mg;
  • Tea – 30 to 100 mg, depending on the type and strength of the brew (both black and green tea contain caffeine);
  • Energy or sports drinks – such as Red Bull or ‘V’ – 80 to 90 mg (Note: regardless of whether you’re pregnant/ breast-feeding/ none of the above, I hope you stay away from energy drinks – studies are consistently showing an increased chance of death in those who drink them);
  • Dark chocolate bar – 40 to 50 mg per 55 g serve;
  • Guarana – can contain up to 100 mg per 1 g of guarana;
  • Caffeine tablets – such as No-Doz – 100 mg per tablet.

SUMMARY – it seems the occasional cup of coffee (or other caffeinated beverage) isn’t going to hurt, but based on the evidence available, caffeine is a case of where less is probably better. If in doubt about your intake or you have any concerns regarding your caffeine intake, please see/ask your healthcare provider.


  • Dorostghoal M, Erfani Majd N, Nooraei P. Maternal caffeine consumption has irreversible effects on reproductive parameters and fertility in male offspring rats. Clin Exp Reprod Med. 2012 Dec;39(4):144-52. doi: 10.5653/cerm.2012.39.4.144. Epub 2012 Dec 31.
  • Barbieri RL. The initial fertility consultation: recommendations concerning cigarette smoking, body mass index, and alcohol and caffeine consumption. Am J Obstet Gynecol. 2001 Nov;185(5):1168-73. Review.
  • Hakim RB, Gray RH, Zacur H. Alcohol and caffeine consumption and decreased fertility. Fertil Steril. 1998 Oct;70(4):632-7. Erratum in: Fertil Steril 1999 May;71(5):974.
  • Bolúmar F, Olsen J, Rebagliato M, Bisanti L. Caffeine intake and delayed conception: a European multicenter study on infertility and subfecundity. European Study Group on Infertility Subfecundity. Am J Epidemiol. 1997 Feb 15;145(4):324-34.
  • Sengpiel V, Elind E, Bacelis J, Nilsson S, Grove J, Myhre R, Haugen M, Meltzer HM, Alexander J, Jacobsson B, Brantsaeter AL. Maternal caffeine intake during pregnancy is associated with birth weight but not with gestational length: results from a large prospective observational cohort study. BMC Med. 2013 Feb 19;11(1):42. [Epub ahead of print]
  • Loomans EM, Hofland L, van der Stelt O, van der Wal MF, Koot HM, Van den Bergh BR, Vrijkotte TG. Caffeine intake during pregnancy and risk of problem behavior in 5- to 6-year-old children. Pediatrics. 2012 Aug;130(2):e305-13. doi: 10.1542/peds.2011-3361. Epub 2012 Jul 9.
  • Laughon SK, Powers RW, Roberts JM, Parana S, Catov J. Caffeine and insulin resistance in pregnancy. Am J Perinatol. 2011 Aug;28(7):571-8. doi: 10.1055/s-0031-1274511. Epub 2011 Mar 4.
  • Al-Saleh I, El-Doush I, Grisellhi B, Coskun S. The effect of caffeine consumption on the success rate of pregnancy as well various performance parameters of in-vitro fertilization treatment. Med Sci Monit. 2010 Dec;16(12):CR598-605.
  • Schneider PE, Alonzo G, Nakamoto T, Falster AU, Simmons WB. Effects of caffeine intake during gestation and lactation on the acid solubility of enamel in weanling rats. Caries Res. 1995;29(4):285-90.
    Schneider PE, Miller HI, Nakamoto T. Effects of caffeine intake during gestation and lactation on bones of young growing rats. Res Exp Med (Berl). 1990;190(2):131-6.

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