PMS or Pregnancy?

PMS or Pregnancy?
by Dr. Daniel J. Heller

It is understandable that women are sometimes confused as to whether their symptoms are the result of PMS or pregnancy, because there really is a lot of overlap between the symptoms of the two. And, of course, a missed cycle or a late period can certainly make the question feel much more urgent. Whether PMS symptoms or pregnancy symptoms, both occur because of changing hormones, so they have related causes as well.

However, PMS will never cause a positive pregnancy test, and the symptoms of the second and third trimesters of pregnancy, and even of the second half of the first trimester, are usually distinguishable from the symptoms of premenstrual syndrome. Most women only experience PMS symptoms for a few days or at most a week before their periods (though we've met plenty of women whose PMS lasts over two weeks!), so the question "Is it PMS or is it pregnancy?" should usually only last several days for most women.

Signs of Pregnancy or PMS?

• Bleeding: Minor bleeding can be normal early in the first trimester of pregnancy. Bleeding is not, however, a symptom of PMS. In fact, the onset of menstrual bleeding almost always brings relief from premenstrual symptoms. Heavy bleeding, or bleeding with severe cramping or fever when you're pregnant is not normal, however, and you should consult a health care provider immediately. Heavy bleeding and cramping can be caused by many conditions besides pregnancy.
• Breast tenderness: Breast tenderness can be a symptom of pregnancy or PMS. There is no detail or characteristic of breast tenderness alone that can distinguish PMS from pregnancy. You can read more about PMS breast tenderness.
• Fatigue: Fatigue can be a sign of PMS or pregnancy, though fatigue has many possible causes. During the latter stages of pregnancy, anemia can cause fatigue, but more often the cause is probably just a need for more rest! In some women, fatigue can be the very first sign of pregnancy. Since fatigue is so common, it is not a reliable sign as to whether you might be pregnant or not. PMS fatigue, like most PMS symptoms, usually gets better with the onset of the period. Fatigue that gets worse during the blood loss of the menses could be a sign of anemia.
• Fever: Fever is not a normal symptom of either pregnancy or PMS. In fact, fever in pregnancy requires the attention of your health care practitioner in order to rule out a serious problem. However, you might experience fever during PMS if you have another condition, such as chronic fatigue syndrome (sometimes called CFIDS) or an autoimmune condition. In addition, some women experience hot flashes, or alternating hot and cold feelings during PMS, but usually without a fever.
• Food cravings/appetite changes: Cravings and increased appetite are hallmarks of both PMS and pregnancy, to the point where both have almost become shorthand or clichés for the two conditions. While there are no specific food cravings that would distinguish PMS from pregnancy, PMS food cravings tend to be for comfort foods, chocolate, and sweet or salty "junk food" items. Peculiar pregnancy cravings (we've all heard about pickles and ice cream) are probably more myth than reality, but there is certainly a grain of truth to them. A craving you've rarely or never had before would be more typical of pregnancy than PMS.
• Frequent urination: This is a second and third trimester pregnancy symptom, as the size of the fetus begins to put pressure on the bladder and internal organs. It is not a typical PMS symptom.
• Heartburn/acid reflux: This can be another second and third trimester symptom caused by the pressure and size of the fetus pushing upwards on the abdominal organs, or one that can accompany the nausea and vomiting of morning sickness. Heartburn and acid reflux are not usually thought of as PMS symptoms.
• Low back pain: Low back pain is typical of both PMS and pregnancy, but in pregnancy this is almost always a second and third trimester symptom, not something you'd feel before you were sure you were pregnant—at least, not as a result of being pregnant. PMS low back pain may have a shooting quality to it, although feelings of soreness, aching, throbbing, and tenderness are equally possible. PMS back pain is often the result of pelvic or abdominal pain radiating to the back. Premenstrual back pain can also radiate downward from the back into the legs.
• Mood swings and depression: You might be surprised to learn that mood swings and even depression can be symptoms of pregnancy, though you were probably aware of them as symptoms of PMS. Mood swings and depression tend to occur later in pregnancy when they happen at all. So many physical, emotional, and lifestyle changes and stresses happen during pregnancy that it is not surprising when this occurs. PMS mood swings can run the gamut from depression, anxiety, tension, tearfulness, and anger to irritability and feeling out-of-control or overwhelmed. PMS mood changes aren't necessarily minor, either—they can truly interfere with your life. Severe PMS mood swings may be bad enough to be considered a sign of premenstrual dysphoric disorder (PMDD).
• Morning sickness: While nausea and vomiting occur only occasionally with PMS, as a part of morning sickness they are typical of early pregnancy. In addition, PMS nausea isn't mostly a symptom that occurs early in the day, as does morning sickness. Morning sickness is quite normal in early pregnancy.
• Cramping: Cramping is one of the most typical PMS symptoms, but it is only rarely part of early pregnancy. If you have severe cramping during pregnancy you should see a health care provider immediately.
• Vaginal discharge: Vaginal discharge can occur premenstrually, but it is not a PMS symptom per se. Some changes in, or the onset of, vaginal discharge can be normal during pregnancy.
• Weight gain: While it is true that weight gain occurs in both pregnancy and PMS, there is little danger in confusing the two, since almost all of the weight gained in pregnancy happens during the last two trimesters. Weight gain in pregnancy is not a symptom, it should be noted: it is a normal and healthy part of pregnancy if the weight gain is within the normal range. PMS weight gain is attributable to water retention and often associated with a bloating sensation, both of which are common symptoms of PMS.