Short luteal phase: causes, symptoms and treatment

The menstrual cycle is complex and relies on a number of hormones to ensure each phase operates correctly. 

The four phases of the menstrual cycle are menstruation, the follicular phase, ovulation and the luteal phase.

But what happens if you have, or think you have, a short luteal phase?

We asked Dr Kat Kriedt, who has a specialist interest in reproductive endocrinology and management of recurrent miscarriage, to break down the short luteal phase subject for us.

What is the luteal phase?

Ovulation occurs in between the follicular phase and the luteal phase, and the success of conception is very much reliant on the luteal phase.

The first day of your last period is when a follicle in one of your ovaries prepares to release an egg – this is known as the follicular phase, and ovulation is when the egg is released from the ovary.

The second part of your cycle, once ovulation has occurred, is called the luteal phase. This phase usually lasts around 11 to 17 days, and it’s during this time that your body prepares for the possibility of pregnancy by releasing progesterone to ensure the uterus lining is thick enough for implantation.

What happens during the luteal phase?

Once the egg is released, the follicle becomes a corpus luteum and starts producing progesterone. Progesterone increases the receptivity of the endometrium so that an embryo can implant.

Once the embryo implants in the uterus, the body starts to produce human gonadotropin (hCG) to maintain the corpus luteum and enables it to continue producing progesterone.

By the 10th week of pregnancy, the placenta takes over the progesterone production, and during pregnancy, progesterone levels will continue increasing:

• first trimester: 10 to 44 ng/mL
• second trimester: 19 to 82 ng/mL
• third trimester: 65 to 290 ng/mL

What does a short luteal phase mean?

A short luteal phase is defined as one that lasts eight days or less. If you’re tracking your ovulation and cycle, you may have a short luteal phase if your period arrives 10 days or less after you ovulate.

Progesterone is essential for implantation and developing a successful pregnancy, it helps to ensure the uterine lining is receptive for an embryo to attach itself and develop into a foetus.

A short luteal phase means there is not enough progesterone, which in turn means the uterine lining doesn’t develop, the embryo fails to implant, and the woman will experience an early period.

What causes a short luteal phase?

The follicle in an ovary that contains the egg before ovulation, becomes the corpus luteum, and the primary function of this is to release progesterone.

A short luteal phase can be caused by a failure of the corpus luteum, because if it doesn’t secrete enough progesterone, the uterine lining may shed before the embryo has a chance to implant, causing an early period.

A short luteal phase can also be caused by conditions such as:

• Endometriosis
• PCOS
• Thyroid disorders, such as an overactive or an underactive thyroid or Hashimoto’s
• Obesity
• Anorexia
• Excessive exercise
• Ageing
• Stress

Symptoms of a short luteal phase

Until you start trying to conceive or tracking your cycles, you may not even notice you have a short luteal phase.

Symptoms of a short luteal phase may include:

• Earlier than normal menstrual cycles
• Spotting in between periods
• Infertility
• Miscarriage

Diagnosing short luteal phase

At The Evewell, we focus on understanding the reason for infertility, and there are a number of tests you can undergo to establish if you have a short luteal phase.

Our consultants will likely run blood tests to check levels of:

• FSH (follicle-stimulating hormone), a hormone that regulates ovary function
• LH (luteinising hormone), the hormone that triggers ovulation
• Progesterone, the hormone that stimulates the growth of the uterine lining

In addition, we can conduct ultrasounds to understand the thickness of your lining, or an endometrial biopsy to establish the receptivity or any underlying asymptomatic infections of the lining of the womb.

What treatments are there for a short luteal phase?

Pregnancy can be achieved once the underlying cause of a short luteal phase has been established.

For example, if a short luteal phase results from extreme exercise or stress, decreasing activity levels and managing stress, can help a normal luteal phase return.

Other treatments may include taking progesterone supplements after ovulation to help uterine lining receptivity so it can better support embryo implantation.

If you’re concerned that you may have symptoms of a short luteal phase, or you’re struggling to conceive, book an initial consultation with one of our fertility and gynaecologists who will be able to assess your situation and build a personalised plan.