The Science

1️⃣ Sperm can survive for a few days inside the female reproductive tract.

2️⃣ The fertile window, your time of highest fertility, is the 5-6 days (particularly the 3 days) leading up to and including ovulation.

3️⃣ Waiting until ovulation happens before you have intercourse is a bad strategy…..this results in very few, if any, pregnancies (we know this from research studies of couples trying to conceive).

Pro Tips:

So how do you know when you’re about to ovulate?

✅ Use ovulation predictor kits (OPKs), which measure the hormone surge in your urine that occurs approximately 24 hours before you ovulate. Digital OPKs are the easiest to read and interpret - you basically pee on a stick like a pregnancy test, and the kit will tell you if it's one of your high fertility days or your peak fertility day.

🛑 What’s NOT the most effective strategy? Timing intercourse using BBT (basal body temperature) charts. These show you the temperature shift that occurs AFTER OVULATION due to increased progesterone levels. Charting your daily temperature is also a great way to ratchet up your stress and frustration levels, so feel free to toss out the thermometer and charts - I give you permission!

🛑 Another key point: apps that track your period CANNOT tell you for sure that you’re ovulating. Still, similar to BBT charts, they might be helpful in showing you which cycle days have been in your fertile window in the past (the app uses these to predict which days might be in your fertile window coming up).

✅ A final word about sex - if you want to have intercourse every day during your fertile window, knock yourself out. In real life — with two people’s busy, exhausting schedules — this can be stressful and unrealistic. Every other day is sufficient!

(Note: This post is obviously about fertility for opposite-sex couples; we’ll talk about fertility options for same-sex couples in future posts.)