The single most important supplement to start before pregnancy is folic acid, but it’s far from the only thing that can improve your chances of conceiving. A combination of the right prenatal nutrients, targeted supplements for egg and sperm quality, dietary changes, and in some cases prescription medications can meaningfully shift the odds in your favor. What works best depends on your age, how long you’ve been trying, and whether an underlying condition like PCOS is involved.
Folic Acid: The Non-Negotiable Starting Point
Every woman planning to get pregnant should take 400 to 800 mcg of folic acid daily, starting at least one month before trying to conceive and continuing through the first two to three months of pregnancy. The U.S. Preventive Services Task Force makes this a universal recommendation because folic acid dramatically reduces the risk of neural tube defects like spina bifida. Most prenatal vitamins contain the right amount, so if you’re already taking one, you’re likely covered.
What to Look for in a Prenatal Vitamin
A good prenatal vitamin does more than deliver folic acid. During pregnancy, your body needs 27 mg of iron daily, 220 mcg of iodine, and 450 mg of choline. Many prenatal vitamins fall short on choline and iodine, so check the label. Iodine supports your baby’s brain development from the earliest weeks, and choline plays a similarly critical role that’s often overlooked. If your prenatal doesn’t contain enough of either, a separate supplement can fill the gap.
Vitamin D and Fertility
Your vitamin D level has a surprisingly strong connection to conception. Women with sufficient blood levels of vitamin D (at or above 50 nmol/L, roughly 20 ng/mL) were nearly three times more likely to achieve a clinical pregnancy than women with lower levels, with pregnancy rates of 64% versus 39% in one study. Many people are deficient without knowing it, especially those who live in northern climates, have darker skin, or spend most of their time indoors. A simple blood test from your doctor can tell you where you stand, and supplementation is inexpensive if you need it.
CoQ10 for Egg Quality
Coenzyme Q10 (CoQ10) is one of the most promising supplements for women concerned about egg quality, particularly those over 35. It works by supporting the energy-producing machinery inside your cells, which eggs depend on heavily. As you age, this cellular energy production declines, and CoQ10 helps compensate. The supplement also acts as a powerful antioxidant, protecting eggs from the kind of DNA damage that accumulates over time and contributes to chromosomal abnormalities.
For women with normal ovarian reserve, 200 mg per day for at least 30 days before trying to conceive is the standard recommendation from clinical research. Women with diminished ovarian reserve have seen better results at 600 mg per day for 60 days. Clinical trials have shown that CoQ10 supplementation increases pregnancy rates in women undergoing fertility treatments, and lab studies show it can reduce the rate of chromosomal errors in eggs from women in their late 30s and 40s.
Inositol for PCOS
If you have polycystic ovary syndrome, inositol is worth knowing about. PCOS is one of the most common causes of irregular ovulation, and a specific combination of two forms of inositol, myo-inositol and D-chiro-inositol, can help restore regular cycles by improving how your body handles insulin. Insulin resistance drives much of the hormonal disruption in PCOS, and inositol targets that root cause.
The ratio matters. A 40:1 ratio of myo-inositol to D-chiro-inositol has the most evidence for normalizing hormones and restoring ovulation. However, a 3.6:1 ratio produced significantly higher pregnancy and live birth rates in a head-to-head trial: 65.5% pregnancy rates versus 25.9%, and 55.2% live births versus 14.8%. This is a meaningful difference, and the 3.6:1 ratio is the only one with direct evidence of improving actual pregnancy outcomes rather than just lab markers.
What Your Partner Can Take
Fertility is a two-person equation. About a third of conception difficulties involve male factors, and several supplements have solid evidence behind them for improving sperm quality.
Zinc is the second most abundant mineral in semen and plays a key role in sperm maturation. In a randomized trial, zinc supplementation improved progressive sperm motility by 18% and sperm concentration by 49%. L-carnitine, an amino acid that helps sperm generate energy, improved motility by 7% and morphology by 5% in a meta-analysis of 23 trials. It also reduced DNA fragmentation in sperm, dropping it from 20% to 14.5% after three months of use. Selenium rounds out the list, supporting the antioxidant systems that protect sperm from damage. Two randomized trials have confirmed benefits for sperm parameters.
These supplements typically need at least three months to show results, because that’s how long it takes for a new batch of sperm to fully develop.
How Diet Affects Your Chances
What you eat matters more than most people realize. The Mediterranean diet, rich in vegetables, fruits, whole grains, olive oil, fish, and legumes, has been studied extensively in the context of fertility. Women with the highest adherence to this eating pattern had clinical pregnancy rates of 50% compared to 29% in those with the lowest adherence. Live birth rates followed the same pattern: 49% versus 27%.
These aren’t small differences. Higher diet quality also improved ovarian response and embryo development in women undergoing fertility treatments, suggesting the benefits extend beyond just ovulation. You don’t need to overhaul your entire diet overnight. Gradually shifting toward more whole foods, healthy fats, and plant-based proteins while reducing processed foods and added sugars moves you in the right direction.
Prescription Medications That Induce Ovulation
If you’re not ovulating regularly and supplements haven’t resolved the issue, prescription medications are the next step. Two drugs are commonly used, and they work differently.
Letrozole blocks estrogen production temporarily, which triggers your brain to release more of the hormones that stimulate your ovaries. It produces ovulation in about 77% of cycles and resulted in a 33% clinical pregnancy rate and 29% live birth rate in a large comparative study. Clomiphene works through a similar feedback loop but by blocking estrogen receptors rather than reducing estrogen production. It achieved ovulation in 66% of cycles, with a 21% pregnancy rate and 17.5% live birth rate. Letrozole is now considered the preferred first-line option for women with PCOS, though both are effective.
These medications are taken by mouth for five days early in your menstrual cycle. Your doctor will typically monitor your response with ultrasound to check how many follicles are developing.
One Supplement to Be Careful With
Vitamin A is essential during pregnancy, but the preformed version (retinol, found in liver and some supplements) becomes dangerous at high doses. Intake above 10,000 IU per day during the first 60 days of fetal development carries a risk of birth defects, particularly urinary tract and heart malformations. Since you may not know you’re pregnant during those earliest weeks, keep your daily retinol intake well below this threshold while trying to conceive. Beta-carotene, the plant-based form found in carrots and sweet potatoes, does not carry the same risk because your body only converts what it needs.
When to Move Beyond Supplements
Supplements and lifestyle changes are a reasonable first approach, but they have limits. The American Society for Reproductive Medicine recommends a formal fertility evaluation after 12 months of trying if you’re under 35, and after just 6 months if you’re 35 or older. Women over 40 may benefit from more immediate evaluation. Don’t wait on these timelines if you have irregular periods (cycles shorter than 25 days, very long cycles, or skipped periods), a history of endometriosis, known uterine or tubal issues, or if your partner has a suspected fertility concern. These situations warrant evaluation right away, regardless of how long you’ve been trying.