So, you spent your 20s going out of your way to not get pregnant, and now that you’re ready to start a family, you’ll have to go out of your way to get pregnant? If this not-so-amusing irony rings true for you, consider yourself in good company. As the number of women waiting until their mid-30s or later to have children increases, so too does the number of women learning firsthand that postponing childbearing can have negative implications for reproductive health. 

Aging and fertility: The things no one taught us in high school  

Women are born with all the immature egg cells (also referred to as oocyte or “eggs”) they will ever have—somewhere between one to two million, each within its own ovarian follicle.¹ During each menstrual cycle, a certain number of follicles are activated in preparation for ovulation, but only one egg will mature to the proper stage and be released from the ovary (an exception being fraternal twins, who derive from different mature eggs). What happens to the activated follicles that don’t make the cut? They are “reabsorbed” by the ovary and effectively lost. 

Here’s where it gets tricky for us ladies over 35. With increasing age, our bodies release more of the hormones that stimulate follicles to develop. This means that more immature eggs become reabsorbed (more specifically, resolve into scar tissue) every cycle, leading to a greater loss of potential eggs as we get older.² Blerg. 

In addition to decreasing in quantity, the quality of a woman’s eggs also decreases with age, and fertility tends to see a precipitous decline in the mid-30s.³ This progressive loss in fertility can result from a host of reasons associated with ovarian ageing, including changes in reproductive hormone levels, irregular menstrual periods, anovulation, endometriosis, and lifestyle factors including tobacco use and excessive alcohol consumption.^1,4,5

In addition, the effects of ovarian aging also contribute to a greater likelihood of chromosomal abnormalities, which may increase the risk of miscarriage or certain congenital defects.⁶ While these facts are sobering, rest assured that a woman’s chances of conceiving a healthy baby after 35 still greatly outnumber the challenges and risks,^7,8 and importantly, there are things we can do to improve the odds! 

Dietary modifications for improving the odds of conception after 35 

In a previous article, “Improving Fertility After 35: Five Easy Tips”, we discussed simple but effective things women of “advanced maternal age” can do to improve their chances of getting pregnant. This article expands on this discussion by looking at research-backed dietary modifications women can make to improve their egg quality and reproductive health. 

Limit your caffeine intake

As formidable a task as cutting back on caffeine may seem, research indicates that it may help you get pregnant faster. This was evidenced by a large retrospective study; examining the effects of caffeine consumption on the number of months it took women trying to conceive to get pregnant.⁹; While the fertility of women who ingested up to 300 mg of caffeine a day did not appear to be affected by caffeine, the likelihood of delayed conception (taking longer than 12 months to get pregnant) was significantly higher for women who ingested more than 300 mg of caffeine a day (equivalent to 2-3 cups of coffee).

Further evidence of the link between caffeine and fertility comes from a prospective study of Danish women.¹⁰ Using data from women’s menstrual cycles and dietary habits, researchers estimated the associations between caffeine exposure and successful conception for women drinking: less than 300 mg/day, between 300-700 mg/day, and more than 700 mg/day. They found a dose-dependent relationship between the amount of caffeine ingested and the likelihood of getting pregnant, such that women who drank between 300-700 mg/day were significantly less likely to get pregnant than women drinking fewer than 300 mg/day, but significantly more likely to get pregnant than women who drank over 700 mg day. (Think of that next time you want to order a “Venti” for the sake of being economical.)

Cut out the sugary beverages

In addition to caffeine, the findings from a recent study suggest that couples trying to conceive should consider reducing their intake of sugar-sweetened beverages. More specifically, this prospective study found that consumption of sugar-sweetened sodas and energy drinks was associated with decreased fertility in both males and females, and that this effect was especially robust in individuals consuming 7 or more sugary beverages a week.¹¹

Consistent with these findings, a number of previous studies have reported similar associations between fertility and consumption of sugary beverages, including a higher risk of ovarian problems in women,¹² poorer semen motility in men,¹³ and fewer eggs and potentially lower fertilization rates in women undergoing IVF.¹⁴ A possible mechanism for the link between sugary beverages and difficulty conceiving is that consuming excess sugar can increase blood sugar imbalances, which can increase oxidative stress and may negatively affect semen quality and ovarian function.¹¹ It is worth mentioning that despite the general convergence of these findings, because the reported studies were observational in design (and thus group conditions were not experimentally controlled) we cannot draw any definitive conclusions about the relationship between sugary beverages and the potential for pregnancy from these data. 

Take your Omega-3s

Sorry to revisit this bit of grimness, but remember our discussion of how the quality and quantity of a woman’s ovarian egg reserve degrades with age, which can lead to a greater incidence of pregnancy loss and chromosomal abnormalities in women over 35? Well, it’s all still true, but guess what? Multiple lines of research suggest that omega-3 fatty acids play important roles in early reproductive events, and may promote egg quality and reproductive success.^15,16

More specifically, several human and animal studies suggest that increasing one’s EPA and DHA intake through diet or supplementation has the potential to prolong certain reproductive functions into advanced maternal age.^17,18 For example, a recent observational study examining the effects of consuming different types of dietary fats on female fertility found that a high intake of trans fatty acids was associated with decreased fertility in humans, whereas a high omega-3 fatty acid intake was associated with greater fertility.¹⁹

Further evidence of the relationship between omega-3s and reproductive health comes from an experimental study with mice.¹⁸ (Don’t worry, the mice weren’t harmed—just made to eat and procreate. Or as scientists refer to it, “made to feel Italian.”) In order to see how a long-term diet rich in omega-3s would affect the mice’s reproductive success with aging, researchers fed several generations of mice a diet high in EPA and DHA. They found that lifelong consumption of an omega-3 rich diet prolonged reproductive function into advanced age, whereas a diet rich in omega-6s was associated with poor reproductive success in later age. Of note, the researchers found that even a short-term diet high in EPA and DHA could improve oocyte quality.

Inspired by these findings, a different set of researchers examined the relationship between omega-3 fatty acids and ovarian reserve by examining fatty acid levels and the number of ovarian follicles in mice.¹⁸ They found a strong, positive correlation between DHA and EPA serum levels and ovarian follicle counts, along with a strong negative correlation between the omega-6:omega-3 ratio and follicle counts.  

Okay, so what does this mean? Basically, the mice with higher levels of EPA and DHA had more egg follicles left (i.e., greater potential to produce offspring), whereas mice who had higher omega-6 and lower omega-3 levels had significantly fewer remaining eggs (lower potential to produce offspring). Though further research with human populations is needed, these findings suggest that increasing omega-3 intake through fish or fish oil may provide an effective strategy for delaying ovarian ageing and promoting egg quantity and quality.²¹

Putting it all together

While none of these dietary modifications will turn back the hands of your biological clock, research does suggest that incorporating omega-3s into your diet and reducing your intake of caffeinated and sugar-sweetened beverages can potentially help you get pregnant faster and more easily. 

What’s a Frappuccino done for you lately?