IVF.com reports that in a 1999 study of 100 women who abstained, or 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 more than one cup of coffee per day.

In another study from 1989, 104 healthy women who were actively trying to conceive for three months were interviewed about their consumption of caffeinated beverages. In their subsequent cycles, women who consumed more than the equivalent of one cup of coffee per day were half as likely to become pregnant, per cycle, as women who drank less. It would seem that the more a woman drank, the lower her chances for becoming pregnant.

The statistics are relentless…

Between 1992 and 1995 a Danish survey of 423 couples was carried out, with women between the ages of 20 and 35, living with their partner and intending to get pregnant for the first time. The survey revealed that compared with women with a very small caffeine intake, those with a moderate intake of caffeine had a lower chance for conception and those with a higher consumption had an even lower chance for pregnancy, again. This information held up after adjustments were made in consideration of weight, diseases of the female reproductive organs, semen quality, duration of the menstrual cycle and alcohol intake.

In 2005 a study published in the journal Diabetes Care demonstrated that caffeine makes it more difficult for insulin to control blood sugar. This condition, called insulin resistance, can cause a woman not to ovulate. Commonly, women suffering with obesity are likely to have insulin resistance. Researchers also believe there may be a link between insulin levels and a problem called PCOS (Polycystic Ovary Syndrome). Women suffering from PCOS generally have an excess of insulin in their bodies, which appears to increase the production of androgen, a hormone that affects the development and release of eggs.

In 1993 the American Journal of Epidemiology stated the following, according to Hatch EE, Bracken MB: Some studies have found a link between high levels of caffeine consumption by women and delayed conception. Those who consumed more than 300 mg of caffeine per day were twice as likely to have conception delayed for a year or more.

In 1997 in the American Journal of Epidemiology stated according to Bolumar.F, Olsen J, Rebagliato M, and Bisanti L that a European study group on infertility and subfecundity linked high caffeine intake to delayed conception, but only in women consuming about four cups of coffee per day (500mg).

So, Does Caffeine Affect Fertility?

Well you be your own judge. Probably a cup of coffee a day or a bar of chocolate generally will be no problem. In other words, less than 300mg a day would be a moderate intake to achieve.

However if you are having difficulties in trying to get pregnant then it would be worth gradually giving it up for a while as it could be just the thing that is preventing you conceiving. If you are a big coffee drinker then wean yourself down gently to avoid headaches and irritability and other negative feelings.

Remember, because caffeine is a diuretic it is important to drink more fluids when consuming caffeine.

Here’s a guide to help you control your caffeine intake:

The average size hot beverage contains the following amount of caffeine (per 250ml cup):

Brewed coffee is 105 – 135 mg
Instant coffee is 57 – 95 mg
Espresso is 100mg
Cappuccino is 100mg
Decaffeinated is 5mg
Tea 50mg
Hot cocoa 5mg (per 8oz)

Other sources of caffeine:

Energy drinks contain 80 mg (per 250 ml can)
Coca Cola has 48.75mg (per 375ml can)
White Chocolate contains 20 mg per 100g
Dark Chocolate contains 65 mg per 100g