Signs of Pregnancy That Can Be Mistaken for PMS

Pregnancy and PMS (premenstrual syndrome) may have similar symptoms. Signs of pregnancy can occur before a missed period, according to Mayo Clinic. While waiting for a period a woman may easily mistake early pregnancy changes as PMS symptoms. The sudden onset of PMS-like symptoms when they do not normally occur may cause a woman to question whether she is pregnant. The change in hormones during the onset of pregnancy are similar to the hormone fluctuations that occur at the start of the menstrual cycle, according to Mayo Clinic.

Breast Changes

Mayo Clinic identifies breast tenderness and swelling as a symptom of both PMS and early pregnancy. Noticing an increase in size and an increase in sensitivity may be an indicator of pregnancy before a period has even been missed. Mayo Clinic suggests that these breast changes occur due to hormone shifts around two weeks after conception. Unless a woman does not usually experience PMS symptoms such as breast changes, she may not suspect pregnancy as the cause.

Fatigue and Headache


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Fatigue is brought on by rising progesterone levels early in pregnancy, according to Mayo Clinic. suggests that blood volume increases during pregnancy and can cause lower blood pressure because it takes longer for the heart to pump the larger quantity of blood out at one time. Headaches from the increased blood circulation are common. Headaches from hormone changes during PMS are also common. Differentiating between a PMS headache and one caused by pregnancy may be difficult. Both fatigue and headaches may occur as early as one week after conception, according to

Spotting or Light Bleeding

PMS occurs before the uterine lining is shed due to a lack of fertilized egg attaching to the uterine wall according to In some cases women may experience slight spotting and cramping when a fertilized egg attaches to the uterine wall six to 12 days after conception, says the Mayo Clinic. This is called implantation. Menstrual cramps and spotting are attributed to the uterus shedding the lining that was prepared for a fertilized egg. During pregnancy this lining will remain as the fertilized egg will be supported by it, says the Mayo Clinic.