Long Luteal Phase: What Does It Mean?

If you’re faced with the paradox of a late period and a negative pregnancy test, you might be confused. Could it be a long luteal phase? Is that even a thing? If you’re puzzled by your long luteal phase, you’re not alone. Let’s run through some of the possible causes of a long luteal phase, and what it means when you’re trying to conceive.

What is a long luteal phase?

menstrual cycle hormone level luteal phase period follicular phase

First, a quick recap. The luteal phase is the second half of your menstrual cycle, after you ovulate and before your next period arrives. On average, this lasts about 13 to 14 days after ovulation, but can be as long as 17 days depending on the person.

During this time, the leftover ovarian follicle turns into a temporary gland called the corpus luteum. The corpus luteum secretes the hormone progesterone to maintain a soft and nourishing uterine lining in case that a fertilized egg implants. This has the effect of slightly raising your basal body temperature (BBT), so the luteal phase registers as a period of higher temperatures on a BBT chart.

Progesterone levels will stay elevated if you’re pregnant. If you’re not, progesterone drops, and you’ll get your period, spelling the end of the luteal phase.

Long luteal phase cause #1: You got your ovulation day wrong

calendar period menstrual cycle

Whether you have a long or short menstrual cycle, it’s the pre-ovulatory follicular phase of the cycle that tends to vary. In general, the luteal phase should remain more or less the same length. All sorts of factors such as alcohol, caffeine and exercise can influence follicular phase length.

For this reason, even if you predict your ovulation date with test kits or tracking your cervical mucus, sometimes our ovaries can throw us a curveball. If you happened to ovulate later in this particular cycle than you expected, your luteal phase might seem longer.

Long luteal phase cause #2: You are pregnant, but tested too early

pregnancy test kit wonder

Home pregnancy tests for the presence of hCG (human chorionic gonadotropin), a hormone produced as the fertilized egg implants in the endometrium.

It takes a while for a level of hCG to rise enough to show up on a pregnancy test, so if you take a pregnancy test too early and get a negative result when your period didn’t come, you may appear to still be in your luteal phase even though an egg has been fertilized and you’re pregnant. The most accurate time to test is one week after your period was due.

Long luteal phase cause #3: Medical reasons

doctor check

Certain medical conditions can send progesterone a little wacky. This results in the appearance of a longer-than-expected luteal phase.

Polycystic Ovary Syndrome (PCOS)

Polycystic Ovary Syndrome is a condition that causes hormone imbalances. The hormone imbalances can cause ovulation and menstruation to happen irregularly, and sometimes not at all.

Persistent corpus luteum cyst

Also called “Halban syndrome”, this causes an extra secretion of progesterone, which can lead to a long luteal phase.

These conditions can only be diagnosed and treated by a doctor, so get checked out as soon as possible if you’re concerned.

Long luteal phase isn’t necessarily a cause for alarm

BBT chart

If you notice that your luteal phase in general tends towards the long side before you get your period, this doesn’t necessarily mean anything negative for your fertility goals. In fact, it tends to be a short luteal phase that’s more of a worry when you’re trying to conceive, as the lower progesterone levels may not give a fertilized egg a chance to successfully implant in the uterus.

It may not always show when you’re about to ovulate, but keeping accurate records of your Basal Body Temperature is a great way to measure your luteal phase. A luteal phase with elevated BBT which is 3 days longer than your previous record for the longest luteal phase can be a sign of pregnancy. If you’re still not seeing a positive pregnancy test after this, see a doctor to clear up any confusion.