Pregnancy and Periods

7 Illnesses Mimicking Pregnancy and Periods

Pregnancy and periods often come with many unwanted symptoms, most of which, unfortunately, are simply part and parcel of having a uterus.

Ectopic pregnancies cannot lead to successful births as the fertilized egg will not move to the uterus on its own and cannot be moved there surgically, and the fallopian tube cannot accommodate the size of a growing foetus.

However, sometimes problems that seem related to periods or pregnancy can be the sign of something else, perhaps something more serious.

iTHINK discusses illnesses and conditions that mimic the symptoms of periods and pregnancies, how you can tell the difference, and what to do about it.



Pseudocyesis, or false pregnancy, is when a woman believes that they are pregnant and experiences many of the symptoms of pregnancy, but they are not carrying a child.

Some of the symptoms of false pregnancy include missed periods, weight gain and a swollen stomach, breast tenderness and occasionally milk production, nausea, and feeling imagined foetal movement.

The cause of pseudocyesis remains unknown but doctors theorize that psychological factors make the body believe that it is pregnant.

An intense desire to become pregnant can lead to a woman experiencing some symptoms that may be interpreted as those of pregnancy.

Her brain then accepts these symptoms as signs of pregnancy and releases pregnancy hormones, leading to further pregnancy symptoms.

Ovarian Cancer

Pregnancy and Periods

Ovarian cancer can mimic some of the symptoms of pregnancy, such as pelvic and abdominal pains and discomfort, bloating, constipation, frequent urination, abnormalities in your menstrual cycle, fatigue and nausea.

However, whereas pregnancy is also often accompanied by PMS, missed periods, breast
swelling and tenderness, and weight gain, these are not symptoms of ovarian cancer.

If you are experiencing many of the above symptoms, a pregnancy test can confirm whether pregnancy is the cause behind them. But if the test comes up negative, it might be a good idea to see a medical professional, especially if the symptoms persist.

Ovarian cancer is the abnormal proliferation of cells that make up or exist around an ovary. The cluster of cells eventually forms a tumour, which grows larger as the disease progresses, and can spread to other organs in the body.

The danger with ovarian cancer is that the symptoms only begin to show in the later stages of the disease, such as when the ovarian tumour is large enough to press against abdominal organs. The only symptom that occurs in the early stages is abnormality in the menstrual cycle.


Abnormal menstrual cycles can also be caused by anovulation. Anovulation is when an egg does not mature as it is supposed to during the cycle and thus is not released by the ovaries.

In short, it is when a woman does not ovulate. Anovulation can cause irregular menstrual cycles or even stop them completely, which might be mistaken as a pregnancy.

However, when anovulation occurs, a woman cannot get pregnant as no egg is released. Some women may experience anovulation during one cycle and then return to their normal menstrual cycle, while others might experience chronic anovulation.

The causes of anovulation are varied, and the condition is not always unwanted. Some types of birth controls release hormones that stop ovulation from occurring and prevent pregnancy.

However, other factors can cause anovulation even when a woman wants to become pregnant. Some drugs such as steroids, epilepsy drugs, or cancer treatments can cause anovulation. If this is the case, doctors can sometimes suggest alternative treatments or provide medication to encourage ovulation.

Ectopic Pregnancy

Pregnancy and Periods

An ectopic pregnancy occurs when an egg is fertilized outside of the uterus and begins to grow there. This usually occurs in the fallopian tubes and can be very dangerous as the growing egg can rupture the tube.

As an ectopic pregnancy does involve fertilization and the beginnings of a pregnancy, the symptoms associated with it are at first similar to a regular pregnancy. This includes missed periods, breast tenderness or swelling, and nausea.

Ectopic pregnancies also cause abnormal vaginal bleeding and pelvic pain, which could once again be symptoms of a regular pregnancy but should be reported to your doctor even in the case of a regular pregnancy.

As ectopic pregnancies progress, the symptoms begin to worsen and may even become life-
threatening if left untreated for long enough. These symptoms include sharp abdominal and
pelvic pains, weakness, dizziness, and fainting.

Ectopic pregnancies cannot lead to successful births as the fertilized egg will not move to the uterus on its own and cannot be moved there surgically, and the fallopian tube cannot accommodate the size of a growing foetus.

If the fallopian tube ruptures, it can cause heavy internal bleeding and even death. So, if you experience severe symptoms and pains as well as the other symptoms involved in pregnancy, seek medical advice and get treatment as soon as possible.


Endometriosis is another condition that can cause discomfort or pain in the abdominal region, thus mimicking periods or pregnancy. It occurs when endometrial tissue grows outside of the uterus lining.

This often means that the tissue is growing in the fallopian tubes or ovaries. The endometrial tissue growing outside the uterus progresses in the same way as the uterus lining: it becomes thicker and eventually breaks down and bleeds.

However, unlike in the uterus, this tissue does not have a way to leave the body and remains inside it.

Endometriosis can cause pain during periods, sexual intercourse, and when going to the bathroom. It can also result in overly heavy bleeding during your period or bleeding between periods, as well as infertility. Fatigue, bloating, and nausea are also common symptoms of endometriosis.

Unfortunately, these are also symptoms of pregnancy and periods, which makes endometriosis difficult to diagnose. But if symptoms like those mentioned above are impacting your ability to function in day-to-day life, it’s a good idea to seek help from a doctor.

Fibrocystic Breast Disease

Pregnancy and Periods

One of the most common symptoms of both pregnancy and periods is feeling swelling or tenderness in the breasts. However, swollen and tender breasts can also be a sign of fibrocystic breast disease.

This condition is non-cancerous and is not dangerous, but it can cause discomfort and lumpiness in the breasts. Fibrocystic breast disease can also make breast cancer detection more difficult as cancerous lumps might be mistaken for changes due to the disease.

Most of the time, fibrocystic breast disease doesn’t require invasive treatment. Painkillers and cold compresses can be used to reduce discomfort. The symptoms are often aggravated just before your period, and thus tend to disappear after menopause.

Depression and Anxiety

Depression and anxiety can both mimic the emotional symptoms of Premenstrual Syndrome (PMS). Premenstrual Syndrome is a very common affliction that affects many women in the days leading up to their period.

PMS impacts both physical and emotional health. Some of the emotional symptoms associated with PMS are low mood, insomnia, irritability, social withdrawal, poor concentration, and feeling anxious.

These are similar to some of the symptoms of depression and anxiety, but whereas PMS should only impact your life right before your period, depression and anxiety can be present throughout the entire menstrual cycle.

PMS can also increase the negative impact of depression and anxiety, so you might feel
even worse than usual before your period starts.

According to the American College of Obstetricians and Gynaecologists, approximately half of women seeking PMS treatment have either anxiety or depression. If you’re feeling the emotional impact of PMS for long stretches of time, it might be worth seeking advice from a medical professional to see if you have depression or anxiety.

However, these are among the few of the illnesses which mimick pregnancy and period symptoms.