Night shifts and 8 other surprising things that can affect your fertility

Your chances of pregnancy can be affected by a number of surprising factors - This content is subject to copyright.

A study conducted by Harvard University has revealed that women who work night shifts are potentially more likely to suffer from infertility problems. Women working unsociable hours had a 28% reduction in eggs in comparison to those who worked during the day. Researchers believe that this could be due to the disruption to a woman's circadian rhythm caused by irregular shift patterns.

With one in seven couples (approximately 3.5 million people) in the UK and 12% of women ages 12 to 44 in the United States experiencing fertility problems, and more and more women delaying pregnancy for work or financial reasons, the question of what (beyond age) can impact the chances of conception is a hugely important issue.

Research suggests that the reasons behind unexplained infertility are varied, and sometimes, extremely unusual. Here are a few surprising discoveries.

Heavy lifting

Manual labour could have a negative impact on a woman's fertility - Credit: Bloomberg

The same Harvard study that highlighted the impact of night shifts noticed the same effect on the egg count of women whose jobs involved heavy lifting. According to researchers, women seeking fertility treatment whose work included heavy lifting (such as nurses or interior designers) produced 14% fewer eggs than women who did not, and those that were produced were of a poorer quality. This could be due to the stress such repetitive physical exertion puts on the female body and its ability to reproduce.

Consuming too many soft drinks

Both regular and diet soft drinks could reducer your chances of conception

A 2016 study indicated that the frequent consumption of soft drinks could limit a woman's chance of becoming pregnant. The artificial sweeteners used in many diet versions were associated with higher rates of infertility, while added sugar was linked to a lower quality of eggs. While the impact of individual additives needs further scrutiny, it is key to remember that the regular consumption of both diet and regular soft drinks can lead to obesity and diabetes, both of which can impact fertility.

Eating the wrong things (even if you're not overweight)

An unhealthy diet and obesity are both linked to infertility - Credit: Rex

An unhealthy diet and obesity can reduce a couple's chances of conceiving. Two American studies showed that a diet high in trans-fats can damage ovaries and cause lower quality embryos, as well as impacting a couple's fertility. Fertility problems occur both to those who are overweight and those who aren't, but who still eat an unhealthy diet. The good news is that 2016 research indicated that losing a relatively small percentage of body weight (in this instance, 9.7lb) can double a woman's chances of conceiving. Dr Adam Balen, chairman of the British Fertility Society, recommended that women with a high BMI consider restricting calories to 1500 per day, and taking up 35-40 minutes of daily aerobic exercise.

A high-pressure work environment

Last year a study revealed that women working in finance were significantly less likely to conceive through IVF than teachers. Despite the fact that investment banks have some of the best employee health schemes, the pressure of a stressful work environment, combined with volatile markets means that female staff are more likely to skip appointments and forget to take medication. Working in a male-centric environment is also said to have an impact, with teachers and women in PR, sales and marketing (who also have a higher success rate) benefiting from the support of a female environment.

Wine o'clock

The fashion for daily wine consumption among women could have a negative impact on fertility - Credit: Eric Tufford / Alamy

The notorious wine o'clock practised by professional women could potentially negatively impact their fertility. A Danish study of over 6000 women aged 21-45 indicated that those who drank over 14 servings of alcohol per week (equivalent to 7 glasses of wine - higher than NHS guidelines) lowered their chances of conceiving by 18%. The NHS advises that women trying to get pregnant give up alcohol altogether in order to minimise damage to a potential foetus.

Having your tonsils removed

A 2016 study showed that women who have had their appendix or tonsils removed are likely to be more fertile than others. The research, undertaken over 15 years, indicated that women who had had an appendectomy increased their chances of pregnancy by 34%, while those who had had a tonsillectomy increased them by 49%, and those who'd had both by 43%. This disproves the idea that an appendectomy could damage a woman's chances of pregnancy, as previously thought. Fertility expert Prof Allan Pacey, from the University of Sheffield argued that the surgery could have a positive impact on a woman's immune system, improving her fertility.

Kissing the wrong person

A virus passed through kissing could lead to infertility - Credit: Chris Rout / Alamy

In a recent Italian study of women with unexplained primary infertility, 43% of participants were found to have HHV-6A, one of the human herpes viruses. The virus is undetectable in the blood, but it is replicated in the saliva glands, meaning that it can be unknowingly passed on by kissing someone already infected. More research is required, but the findings may signal a breakthrough for the millions of women whose infertility is simply "unexplained".

Having a partner that sleeps too much (or too little)

If men sleep for too long they can be less fertile - Credit: Peter Widmann / Alamy

The male proclivity for a lie-in could have a negative impact on a couple's chances of conceiving. In a survey of over 700 American couples, it was found that men who slept for longer than 9 hours (or less than 6) per night, reduced their chances of conception by over 40%. This is likely to be due to the release of testosterone overnight. The study suggests that peak fecundity could be attained by an average of 8 hours a night, but scientists were quick to point out that forcing a male partner to sleep less in the hope of having a baby was more likely to make them grumpy, more than anything.