Fertility Basics: What to Know Before You Start Trying

Isla Oliver, DNP, CNM, ARNP

We receive a lot of messaging from a very young age about how to prevent pregnancy. That's helpful for a long time — but it often leaves people unprepared when they're ready to start a family and discover it may not be as easy as they were led to believe.

How do I know if I'm fertile?

There are a few common signs of normal fertility to look for.

Regular periods. This means they occur roughly every 26–35 days, with some natural variation of plus or minus a week. When measuring cycle length, count from the first day of bleeding (spotting counts) of one period to the first day of bleeding of the next.

Periods can vary in length (typically 2–7 days) and flow (from spotting to heavy) and still be considered normal. Blood clots are also normal, as long as they're smaller than a lime.

PMS symptoms. While no one enjoys premenstrual syndrome, the hormonal changes behind it — breast tenderness, moodiness, acne, headaches — are actually a good sign. They indicate that your body released an egg that month. Successful ovulation triggers the formation of a corpus luteum, which gradually breaks down before your period; the resulting hormone shifts are what cause PMS symptoms.

Ovulation tracking. Regardless of cycle length, ovulation occurs 12–14 days before your period — this is how long it takes the corpus luteum to break down, and that breakdown is what triggers your period. Since this window is reliable, ovulation falls around day 14 of a 28-day cycle, or around day 21 of a 35-day cycle. Tracking ovulation over several cycles is really about recognizing your personal pattern.

You can also use ovulation predictor (LH) strips, monitor cervical mucus throughout the month, or track your basal body temperature. Hopkins Medicine has a helpful explainer on how these methods work.

In general, if you're having regular periods and showing signs of ovulation, fertility is assumed and no testing is necessary for otherwise healthy people.

When can I get pregnant?

This is where a lot of people were misled growing up. Were you ever told "you could get pregnant any day of the month, even during your period"? While that may apply to adolescents with irregular, 14–40 day cycles, it's not the reality for most adults with regular periods.

Because ovulation occurs 12–14 days before your period, and sperm can survive in the body for up to 5 days, your fertile window spans the 5 days leading up to ovulation.

• 28-day cycle: Ovulation typically falls on days 14–16, so sex on days 9–16 could result in pregnancy.

• 35-day cycle: Ovulation typically falls on days 21–23, so sex on days 16–23 could result in pregnancy.

  
  

To maximize your chances, aim for intercourse every other day during your fertile window. It's also worth noting that the sperm-producing partner shouldn't "save up" — sperm motility and quality are actually best when ejaculation happens every 1–3 days consistently throughout the month. (Source)

Whether or not you decide to be part of that endeavor is entirely up to you!

What else should I be doing?

Several lifestyle factors can meaningfully impact fertility and early pregnancy.

1. Take a prenatal vitamin. Nutrients like folic acid are critical in the first weeks of pregnancy — often before people even know they're pregnant. Start as soon as you decide to try. If cost is a barrier, at minimum take 800 mcg of folic acid daily. I'd also caution against beef organ supplements like Primal Queen as a substitute; clinically, I've seen significant side effects from these products, and they typically don't contain adequate folic acid.

   
   

2. Both partners should avoid alcohol, tobacco, and marijuana. Research increasingly links the health habits of the sperm-producing partner to pregnancy complications, including nausea, hyperemesis, preeclampsia, and potentially preterm birth. (Source 1, Source 2) This is all the more reason for both partners to begin the lifestyle changes the gestating partner will need during pregnancy. And yes — the evidence is growing that marijuana use can negatively affect pregnancy and fetal development. (ACOG)

   
   

3. Build healthy habits now. "I'll start working out when…" "I'll eat better when…" These are easy thoughts to have when planning for a family. The reality is that it's much easier to establish exercise, nutrition, and stress management routines before you're tired, nauseated, or navigating the emotional weight of pregnancy. Start now, so these habits feel natural by the time you need them most.

   
   

4. Check your immunity. As more people are having children later in life, we're seeing higher rates of waning immunity to diseases like measles, mumps, and rubella. Your baby will depend on your immunity for early protection, and vaccines for these diseases cannot be given during pregnancy or in the four weeks before. Ask your provider for a titer test at the start of your conception journey.

   
   

How do I know if something is wrong?

It's important to remember that conception normally takes many months. We only get one opportunity per cycle, so give your body grace — growing a human takes time.

Reach out to your provider if:

1. You're not seeing signs of ovulation, or you're not having regular periods.

2. You're under 35 and have been trying with timed intercourse during your fertile window for 12 months.

3. You're 35 or older and have been trying for 6 months.

4. You have questions or need personalized guidance.

   
   

Depending on your situation, your provider may recommend labs, imaging, or coaching on cycle tracking. In some cases, medication to stimulate ovulation may be discussed.

Learning about conception can feel like picking up a whole new language. But you are not alone in this! Preconception counseling is something we're always happy to offer — and the more openly we talk about it, the more we all get to learn.