Dairy Can Help You Get Pregnant — Everything You Need to Know

What dairy has to do with fertility

Milk, yogurt, ice cream -- unless you're lactose intolerant, I'm betting you're as much a fan as I am. But does your dairy habit interfere with fertility? Cows are milked up to the third trimester of their own pregnancies, so dairy products in the US and other Western countries contain measurable amounts of reproductive hormones, which you then ingest. Early research raised concern that dairy could cause ovulatory dysfunction, based on rat studies where a high-"galactose" diet led to worse ovulation cycles or early menopause. Galactose combined with glucose makes lactose, the main carbohydrate in milk -- so drinking milk means ingesting lactose, which becomes galactose. Women with a rare genetic disorder called galactosemia, who can't properly metabolize galactose, almost universally show greatly diminished ovarian reserves, further pointing at a possible galactose-fertility link.

But it's not that simple: dairy intake is also linked to lower risk of insulin resistance and type 2 diabetes, both of which are linked to ovulatory dysfunction -- meaning more dairy could improve ovulation by that route. One study found women drinking 3+ glasses of milk daily had a 70% lower risk of infertility than non-milk-drinkers. This is a genuinely complex, sometimes contradictory picture. Let's dig deeper.

The Nurses' Health Study on dairy and fertility

Just like with carbohydrates and protein, the Nurses' Health Study looked closely at dairy. Total dairy consumption didn't matter much on its own. But splitting it into low-fat dairy (skim milk, sherbet, yogurt, cottage cheese) versus high-fat dairy (whole milk, cream, ice cream, cheese) told a different story: adding 1 serving of low-fat dairy per day was linked to an 11% higher risk of ovulatory infertility, while adding 1 serving of high-fat dairy was linked to a 23% lower risk. One possible explanation is that low- and high-fat dairy carry different estrogen concentrations, which regulate a hormone called Insulin-Like Growth Factor 1 that's tied to fertility. And just as with vegetable protein, the benefit of high-fat dairy was more pronounced in older women.

Is the low-fat vs. high-fat difference real?

A more recent study, following over 1,000 women in Europe and the US in the early stages of trying to conceive for a year (about two-thirds got pregnant), found dairy consumption overall wasn't strongly related to fertility either way, and -- unlike the Nurses' Health Study -- found no meaningful difference between low- and high-fat dairy. The one consistent finding across both: dairy isn't harmful. Whether high-fat specifically helps remains a genuinely open question.

Evidence from IVF studies

IVF studies offer a cleaner comparison since everyone undergoes the same well-controlled treatment, with outcomes like implantation, clinical pregnancy, and live birth. Harvard researchers tested whether dairy intake and specific components like calcium predicted these outcomes, and found that women in the top 25% of dairy consumption had a 21% higher chance of live birth than low consumers -- with the improvement especially pronounced in women 35 and older, again echoing the Nurses' Health Study pattern. Unlike that study, though, this one found no difference between full-fat and low-fat dairy.

What this means for women over 35

Put together, this is a meaningful picture for women who already have a harder time conceiving: those over 35. Increasing dairy intake could plausibly help, and since live birth rates improved even where implantation and pregnancy rates didn't move much, it's possible dairy specifically helps maintain a pregnancy once it starts. That tracks with other findings: drinking milk during pregnancy is linked to a larger placenta and higher birth weight.

The role of calcium

Dairy is also your main source of calcium, and a developing fetus draws its calcium entirely from you. Getting enough during pregnancy is linked to lower risk of preeclampsia, high blood pressure, and low birth weight. Your bone density will dip during pregnancy and breastfeeding to supply the baby, then bounce back afterward. Prenatal vitamins contain some calcium, but not enough on their own -- so it's worth getting more elsewhere too: dairy, but also kale, broccoli, spinach, sardines, and calcium-fortified orange juice.

Estrogens naturally occurring in dairy

Just like soy, dairy contains phytoestrogens (plant/animal-derived compounds that mimic estrogen), which cows pick up from grasses and pass through milk. Isoflavones specifically are highest in organic milk. Higher isoflavone levels seem to help couples undergoing infertility treatment specifically, but studies show couples conceiving naturally are unlikely to notice a benefit -- and long-term high isoflavone intake has its own downsides, including a thicker endometrium and possible interference with ovulation. Skim and whole milk have similar phytoestrogen levels either way, so if you want more isoflavones, organic whole milk is the pick; otherwise regular or free-range milk is fine.

The bottom line on dairy and fertility

Regular dairy consumption gets you a needed dose of calcium for when you're pregnant, and it's likely to boost your conception odds at least a little -- most clearly for women undergoing IVF. Whether high-fat beats low-fat specifically remains genuinely unsettled, though one prominent study suggests it. One last note: stick to milk labeled "rBST free," meaning the cows weren't given artificial growth hormones to boost production.

References

Daxenberger, Ibarreta & Meyer (2001). Human Reproduction Update, 7(3), 340–355. Pape-Zambito, Roberts & Kensinger (2010). J Dairy Science, 93(6), 2533–2540. Cramer, Xu & Sahi (1994). Am J Epidemiology, 139(3), 282–289. Bandyopadhyay et al. (2003). Human Reproduction, 18(10), 2031–2038. Swartz & Mattison (1988). Fertility and Sterility, 49(3), 522–526. Guerrero et al. (2000). J Pediatrics, 137(6), 833–841. Spencer et al. (2013). J Clin Endocrinol Metab, 98(7), E1257–E1265. Pereira et al. (2002). JAMA, 287(16), 2081–2089. Tobias et al. (2015). Diabetologia, 58(4), 707–715. Greenlee, Arbuckle & Chyou (2003). Epidemiology, 14(4), 429–436. Chavarro, Rich-Edwards, Rosner (2007). Obstetrics and Gynecology, 110(5), 1050–1058. Wolford & Argoudelis (1979). J Dairy Sci, 62(9), 1458–1463. Magon, Malik & Agrawal (2011). Indian J Endocrinol Metab, 15(7), 246. Afeiche, Chiu, Gaskins et al. (2016). Human Reproduction, 31(3), 563–571. Heppe et al. (2011). Am J Clinical Nutrition, 94(2), 501–509. Olsen et al. (2007). Am J Clinical Nutrition, 86(4), 1104–1110. Beinder (2007). Therapeutische Umschau, 64(5), 243–247. Nørskov, Givens & Purup (2019). Food Chemistry, 295, 1–9. Unfer et al. (2004). J Soc Gynecol Invest, 11(5), 323–328. Unfer et al. (2004). Fertility and Sterility, 82(1), 145–148. Jefferson (2010). J Nutrition, 140(12), 2322S–2325S. Antignac (2004). Food Chemistry, 87(2), 275–281.