The LH Surge is described as a sudden and large increase of Luteinizing hormone (LH) levels in the blood leading to a LH peak, which happens in the middle of your menstrual cycle. The LH surge is required for ovulation and normally has a duration of 3 days, after which the levels go back down to the baseline.
Sources:
- Direito A. et al. Relationships between the luteinizing hormone surge and other characteristics of the menstrual cycle in normally ovulating women. Fertility and Sterility. 2013:99 (1), 279-285. https://www.fertstert.org/article/S0015-0282(12)02135-8/fulltext#sec1.3.4
- Park S.J et al. Characteristics of the urinary luteinizing hormone surge in young ovulatory women. Reproductive Endocrinology.2007: 88(3). P684-690. https://www.fertstert.org/article/S0015-0282(07)00160-4/fulltext
- FDA. Ovulation (Urine Test). https://www.fda.gov/medical-devices/home-use-tests/ovulation-urine-test (accessed 5. August 2020)
