What is LH surge?

The LH surge is a term used to describe the rise in the hormone called luteinizing hormone and it happens on the 14th day of the menstrual cycle. Once the luteinizing hormone rises, ovulation is triggered after a period of 36 to 40 hours. After the egg is released, it can live in the uterus for approximately 24 hours. This is also called the “fertile window”, which is the only time during the menstrual cycle when the woman can become pregnant.

During your menstrual cycle, the LH surge comes naturally after the 14th day, but if you enter fertility treatment, either with donor sperm or your partner's sperm, you will receive a trigger shot, that causes your body to produce the hormone needed to create the LH surge and therefore cause ovulation.

Read more about how ovulation works here.

What does LH surge indicate?

The luteinizing hormone (LH) surge signals that ovulation is imminent. Ovulation is an important part of the female reproductive system where an egg is released from the ovary. The hormone is produced by a part of the brain known as the anterior pituitary gland. Throughout the majority of the menstrual cycle, LH levels remain relatively low.

How to detect your LH surge?

It is important to detect and track your LH surge when trying to conceive to increase your chances of conception. The best option to track your LH surge is to monitor your ovulation to establish when your cycle starts and ends. You can use a calendar or an app to track your ovulation and establish when your LH surge may occur. It may take a few cycles to become familiar with the process, so be patient and stay consistent in your efforts.

Do you need LH surge to get pregnant?

The short answer is yes, as you need an LH surge to ovulate and get pregnant. However, some women might struggle to detect their LH surge, as it can be quite brief. It is important to track your LH surge in order to accurately determine your fertile window and increase your chances of becoming pregnant.