Conception date vs intercourse date explained

Illustration of a woman presenting a calendar with icons to show that conception and intercourse dates can differ.

Key points Conception means fertilisation near ovulation, not the day you had sex. The fertile window spans six days and ends on ovulation day. Sperm can survive in the reproductive tract for up to five days, so sex before ovulation can lead to conception later. Implantation happens later again, most often 8–10 days after ovulation. … Read more

Contraceptive Methods You Should Never Mix

Illustration of a woman holding two condoms and raising a stop hand with the headline “Don’t double condoms”.

Some contraceptive pairs reduce protection or add risk. If you want to “double up,” choose methods that complement each other—not ones that fight or cancel out. Below are combinations most people should avoid, plus better substitutes. Pairs you shouldn’t mix Don’t mix Why it’s a bad combo Better instead Two external condoms or an external … Read more

How Effective is Using Two Contraceptives at Once?

Illustration of a woman holding a condom and a pill pack with the headline “Double up, done right”.

Using two methods at the same time can lower pregnancy risk, especially if at least one method protects against user error. The calculator below estimates protection when you combine methods under typical or perfect use. Check your combined protection How the estimate works (plain math) Convert each method’s effectiveness to a failure rate. Example: 95% … Read more

Top Contraceptive Method Combinations for Maximum Protection

Illustration of a woman gesturing to a shield with a plus sign and check marks; headline reads “Best pairings”.

Some pairs of birth control work especially well together. Below are evidence-based combinations that increase pregnancy protection while keeping STI protection in mind. When you want precise numbers for your situation, use our Combined Contraceptive Effectiveness Calculator. How “combined effectiveness” works (in plain English) Each method has a small chance of failure in a given … Read more

Do Ovulation Apps Work? Evidence, Limits & Better Ways to Time Intercourse

Illustration of a woman comparing an ovulation app on her phone with an LH test; headline reads “Do ovulation apps work?”.

Ovulation “prediction” sounds straightforward—until you look at real cycles. Many popular apps lean on calendar math, but ovulation varies by person and by month. Below is what independent studies and guidelines say, where tracking goes wrong, and practical (evidence-based) ways to time intercourse without overcomplicating your life. What the research actually says Key takeaways from … Read more