Trying to understand your odds of pregnancy with using a contraceptive? Get a quick, baseline estimate in seconds. Had a tubal ligation? Check the tubal ligation failure risk for yearly and lifetime odds. If you’re concerned about a recent single encounter, our ‘Am I Pregnant?’ calculator can help you estimate your chances and understand the next steps. Explore … Read more
Updated: 22 Nov 2025 This page explains how different birth control methods change pregnancy chance and how perfect use compares to typical use in real life. If you want to explore example numbers, you can use tools such as the Condom Risk Calculator, the Pill Risk Calculator, the Combine Methods Calculator or the Advanced Pregnancy … Read more
Some health conditions make ovulation less predictable, affect egg quality, or alter implantation. This page gives an overview of common issues such as PCOS, endometriosis and thyroid disorders, and how they might change your chances of pregnancy. If you want to see rough numbers while you read, you can use tools like the Advanced Pregnancy … Read more
Daily habits such as nutrition, movement, sleep, stress and substance use can nudge fertility up or down. This page walks through the main lifestyle factors and simple targets you can discuss with a clinician. If you like working with numbers, you can later use tools such as the Advanced Pregnancy Chance Calculator, the Ovulation Calculator … Read more
Age changes natural conception odds and timelines. You can use the Fertility Calculator by Age to see a per cycle estimate, then come back to this guide to understand what drives those numbers and what to do next. Below is a simple age based model, plus an overview of how fertility tends to change across … Read more
The contraceptive implant is a small etonogestrel rod placed under the skin of the upper arm. Product labels in many countries say to replace it after 3 years of use. Several cohort studies have followed users for longer and have reported very low pregnancy rates in years four and five. Any decision to extend use … Read more
Withdrawal can reduce pregnancy risk compared with having no method at all when it is done very carefully, but in real life it fails often. Research suggests that pre ejaculate usually has little or no sperm when there has not been a recent ejaculation, and that some residual sperm in the urethra may decrease over … Read more
Ovulation “prediction” sounds straightforward, until you look at real cycles. Many popular apps lean on calendar maths, but ovulation varies by person and by month. If you already use an ovulation app or you are thinking about one, this guide brings together what studies and guidelines say, where app based predictions can go wrong, and … Read more