These five little letters play a big role in the fertility game. The acronyms stand for luteinizing hormone (LH) and follicle stimulating hormone (FSH), two substances vital to healthy ovulation.
When estrogen levels fall in a woman's body as part of her natural monthly cycle, the hypothalamus sends a signal to the pituitary gland to produce more. It, in turn, releases FSH, which causes follicles in the ovaries to mature. Once a follicle has grown to a sufficient size, it begins secreting estrogen, which tells the body that an egg is ready for delivery to the uterus.
The pituitary gland then sends out a high dose of LH, which causes the follicle to burst open and release the egg.
If the levels of either of these hormones are either too high or too low, problems with ovulation can occur. Factors such as stress, atypically high or low body weight or a recent loss or gain of weight can adversely affect both LH and FSH, causing irregular or missed periods. Doctors can check for hormonal imbalances through a blood or urine test.