Human chorionic gonadotropin (hCG) is a hormone your body makes in early pregnancy. It is mainly made by tissue that will become the placenta after the fertilised egg has implanted in the uterus. Laboratories usually measure the beta part of hCG, so you will often see “beta hCG” on a blood test report. This is … Read more
Key points Conception means fertilisation near ovulation, not the day you had intercourse. The fertile window usually spans about six days and ends on ovulation day. Sperm can survive in the reproductive tract for up to about five days in the right cervical mucus, so intercourse before ovulation can still lead to conception later. Implantation … Read more
When you are choosing birth control, it is easy to focus on the method itself, but how you use it also matters. The gap between perfect use (no mistakes) and typical use (real life) can change your pregnancy risk in a meaningful way. What “perfect” vs “typical” use means Perfect use Taking the pill at … Read more
Some contraceptive pairs can reduce protection or add risk. If you want to use two methods at the same time, it is usually safest to choose options that complement each other. The combinations below are ones that guidelines generally advise against, together with alternatives you can discuss with a clinician. Pairs you usually should not … Read more
Using two birth control methods at the same time can lower pregnancy risk, especially if at least one method is less dependent on perfect day to day use. The calculator below gives an approximate estimate of protection when you combine methods under typical or perfect use. It is a modelling tool, not a substitute for … Read more
Some people choose to use more than one birth control method at the same time. This page summarises combinations that expert guidance from organisations such as the CDC and WHO generally considers reasonable for lowering pregnancy risk, while keeping STI protection in mind. The best combination for you depends on your health history, medicines, and … 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