Late ovulation: how it can affect your fertility

Ovulation chart

by Emily Gilbert |
Updated on

When you decide to start trying for a baby, the first thing most of us will do is look at tracking ovulation, whether that's by using an ovulation calculator or ovulation test strips. But sometimes, for various reasons, late ovulation can occur, making working out when exactly you should be baby-making tricky.

We spoke to Dr Shazia Malik, Consultant Obstetrician and Gynaecologist at The Portland Hospital (part of HCA Healthcare UK), to find out more about late ovulation including causes and when to seek help.

What is late ovulation?

Ovulation is the release of a mature egg from an ovary each month during the menstrual cycle. It's triggered by the monthly fluctuation of certain hormones, namely: oestrogen, progesterone, luteinizing hormone, and follicle-stimulating hormone.

Everyone’s menstrual cycle is different. On average, ovulation typically occurs around day 14 of the cycle, but it varies from person to person. Late or delayed ovulation is when ovulation occurs after day 21 of your menstrual cycle.

Causes of late ovulation

Late ovulation can occur from time to time in almost any woman. Infrequent late ovulation is not typically a cause for concern, only if it’s consistently late might it be worth investigating.

Common causes of late ovulation includes:


Stress can have a noticeable effect on the menstrual cycle, including ovulation, due to its effect on hormonal balance.


Prolactin (the hormone necessary for breast milk production), suppresses ovulation and menstruation. If you breastfeed exclusively, your period may stop altogether while you’re nursing.  This is not to say you can’t get pregnant, as you can still ovulate from time to time.

Medical conditions, such as PCOS and thyroid disease

PCOS is a condition in which testosterone is overproduced. Excess testosterone can prevent the ovaries from releasing an egg. There is treatment to counteract this when trying to conceive. Your thyroid impacts the pituitary gland, which is a region of the brain responsible for some of the hormones necessary for ovulation. Having either an underactive or an overactive thyroid can cause problems with ovulation. The pituitary gland is vital for the correct functioning of your ovaries – very rarely a small benign tumour called a prolactinoma can make too much of a hormone called Prolactin which can delay ovulation.

Being overweight (obese) or underweight

Being in the obese BMI range can cause delayed or infrequent ovulation. This means that the womb lining has longer to become thicker, and can therefore also cause heavy periods. Weight loss if it’s drastic or over a short period of time can often impair the delicate balance of hormones between your brain and ovaries, so having a direct affect on ovulation. If you lose weight to the extent that your BMI is under the normal range (less than 18.5) it is quite likely that you will suffer either delayed ovulation or no periods at all.

Excessive exercise (especially running)

Too much exercise can play havoc with your hormonal balance – especially running (and this is not just because of weight loss). As with anything, a healthy balance is the key.


Certain hormonal medications or antidepressants, or medication for epilepsy or certain mental health conditions can affect ovulation – so it’s important to discuss these with your doctor.


If not well controlled can have an effect on your hormonal balance.


It’s very common for your hormones to fluctuate in the years leading up to the menopause (when your periods stop completely). So it’s one of the commonest causes of late ovulation (and hence heavier periods).

When it comes to psychological stress and breastfeeding impacting ovulation, changes to menstruation and fertility are usually only temporary. In the case of an underlying medical condition, treatment can often restore normal ovulation and improve a person’s chances of conceiving.

Late ovulation symptoms

There are multiple symptoms of ovulation to look out for and track against your cycle – however, some people don’t experience noticeable symptoms, so it can be tricky to detect on your own. Therefore, this can mean that it can be hard to tell if you’re ovulating late – until you may take more of an interest in this information, such as when trying to conceive.

Symptoms of ovulation

 • Light spotting

 • Higher body temperature (basal body temperature)

 • High libido

 • Light pelvic aching, commonly known as ‘ovulation pains’ which can occur on either side of the body depending on which ovary has released the egg that particular month

 • Changes in vaginal discharge (cervical mucus becomes clear and stretchy like a raw egg white)

Chances of conceiving with late ovulation

Although late ovulation can be frustrating when trying to conceive, it does not necessarily mean that conception won’t occur later in the cycle. Many women who have irregular or late ovulation will successfully conceive.

As the ovulation will be less irregular, it’s imperative to monitor the symptoms your body is showing. This way women can determine when they ovulate, enabling them to more accurately time sexual intercourse.

To monitor these ovulation symptoms, it might be helpful to use an ovulation app, to note and monitor a pattern in symptoms.

If your menstrual cycles commonly fall out of the normal range (21-35 days), then it’s advisable to seek investigation and advice from a specialist. It’s also really helpful to make sure that your weight, stress and exercise levels are as normal as possible – and having sex every other day gives you the best chance of conceiving.

How does late ovulation affect menstruation?

If you have experienced late ovulation, you may experience heavy bleeding when menstruation occurs. In the first half of the cycle, oestrogen peaks, causing the uterine lining to thicken and swell. If anovulation or late ovulation occurs, oestrogen continues to be released, meaning the uterine line keeps growing.

So, when you then have a period (usually 14 days after ovulation), it’s likely to be heavier than normal as the womb lining is thicker than in a normal cycle.

When to see a doctor

It’s best to seek medical treatment if:

 • Your period stops for an extended period (e.g., 90 days or more)

 • Your periods have become irregular, or you are experiencing heavy bleeding

 • You are experiencing severe pain during menstruation

 • Your cycles are fewer than 21 days apart or more than 35 days apart

 • You have struggled with health problems that are linked to fertility issues (such as endometriosis or PCOS)

 • You’re concerned about your inability to conceive

 • You’re experiencing hot flushes or sweats

 • You’re experiencing bleeding between periods or after sex

 • You think you might be on medication that can affect your chances of conceiving (or can have an impact on your baby). In this case, it’s important to discuss this with your doctor before you try to conceive.

Is there a treatment for late ovulation?

If you have an underlying condition, such as PCOS or hypothyroidism, treating these can help regulate ovulation and prevent future anovulation. However, if no cause can be determined, your doctor may suggest certain medications that help to regulate ovulation. Doctors may prescribe:

Letrozole - a fertility drug that stimulates the ovary to work to produce more follicles, helping the release of an egg

Clomiphene (Clomid) - a fertility drug that stimulates the hypothalamus, pituitary gland and ovary to increase the levels of hormones FSH and LH

Human Chorionic Gonadotropins (Pregnyl, Novarel) - HCG induces ovulation

If a treatment cannot be found, and you are trying to conceive, then an alternative method of conception, such as IVF, might be suggested as an alternative. Your doctor will be able to discuss the available options with you.

Medical professionals may also recommend some immediate lifestyle changes to improve reproductive health and regulate your cycle:

 • Avoid smoking and drinking

 • Manage stress

 • Use contraception to protect against STDs that can impact fertility

 • Don’t over-exercise

 • Maintain a healthy diet and weight

What is amenorrhea?

Amenorrhea is the absence of menstruation amongst those who are of reproductive age. It’s often diagnosed if someone who previously menstruated has missed three or more menstrual periods and is not pregnant, nor going through the menopause (secondary amenorrhea).

Primary amenorrhea refers to the absence of menstruation in someone who has not had a period by age 15.

Treatment of amenorrhea depends on the underlying cause but it is often the sign of a treatable condition. With treatment, your regular menstrual cycle will usually resume. Please speak to your doctor if the above criteria applies to you.

Just so you know, whilst we may receive a commission or other compensation from the links on this website, we never allow this to influence product selections - read why you should trust us
How we write our articles and reviews
Mother & Baby is dedicated to ensuring our information is always valuable and trustworthy, which is why we only use reputable resources such as the NHS, reviewed medical papers, or the advice of a credible doctor, GP, midwife, psychotherapist, gynaecologist or other medical professionals. Where possible, our articles are medically reviewed or contain expert advice. Our writers are all kept up to date on the latest safety advice for all the products we recommend and follow strict reporting guidelines to ensure our content comes from credible sources. Remember to always consult a medical professional if you have any worries. Our articles are not intended to replace professional advice from your GP or midwife.