A woman’s ovulation cycle is split into two phases: the follicular phase and the luteal phase. Sometimes having a short luteal phase can be a cause of infertility. Here’s why.

The follicular phase begins just after menstruation and is the phase during which a follicle prepares to release a mature egg. This phase lasts from one week to over a month.

Once an egg is released, the luteal phase begins. This is the phase during which a woman’s body prepares itself for pregnancy. Normally, during the luteal phase, the uterus grows a thick lining into which the fertilized egg will implant to create a pregnancy. The hormone progesterone is responsible for stimulating the development of this thickened lining.

The luteal phase typically lasts between 12 and 16 days. If the luteal phase lasts less than 10 days, it can be very difficult for a woman to become pregnant or maintain a pregnancy. Without enough progesterone, the uterine lining may shed before the fertilized egg is able to implant. If an egg has successfully implanted, the abnormally thin uterine wall may not allow the developing embryo to remain firmly attached. Women with a short luteal phase may be unable to get pregnant or may experience frequent, early miscarriages. Other symptoms of short luteal phase include spotting between periods and early menstrual cycles.

Your doctor can diagnose a short luteal phase with blood tests to check hormone levels and a pelvic ultrasound to assess the thickness of the uterine lining. Anyone can have a short luteal phase, but the following conditions are risk factors:
Endometriosis
PCOS
Under- or overactive thyroid
Anorexia
Obesity
Stress
Excessive exercise

Treating a short luteal phase can greatly increase your chances of becoming pregnant. If a short luteal phase is caused by lifestyle factors, making adjustments such as reducing stress or losing weight may help. Your doctor may prescribe human chorionic gonadotropin (hcG) supplements to help your body produce more progesterone. Your doctor may also prescribe a medication to stimulate your ovaries to produce more follicles.

Not all women respond the same way to treatments for short luteal phase, so your doctor may have to try a few different approaches to help you conceive and carry a healthy baby to term.