A disappearance of symptoms in itself does not have to be a cause for concern. But it is true that a sudden disappearance of symptoms like morning sickness, fatigue, and frequent peeing can signal the possibility of a miscarriage. Miscarriages normally come with totally obvious symptoms, most notably cramping and lower abdominal pain. But sometimes a fetus can pass away and remain in the body. This is referred to as a "missed abortion". In such cases, pregnancy symptoms are likely to go away because hormone levels will suddenly dip, yet you will not notice any bleeding or pain. Your own intuition has an important role to play here. If your pregnancy symptoms went away all of a sudden, and you have seen a big change from one day to the next, it is time to call your doctor or midwife. I think that a good general rule is, "if you are worried and think something is wrong, get it checked out."
Your pregnancy test was positive, you have missed a period, and you experienced at least some of the symptoms that are commonly associated with the first trimester of pregnancy. Perhaps you have suffered from pregnancy nausea (morning sickness), noticed extreme fatigue, more frequent urination, and abdominal swelling. What if you are in the first trimester of your pregnancy and the symptoms that you had suddenly disappear? Does a sudden disappearance of pregnancy symptoms point to a miscarriage? Hormone levels do fluctuate, and with those fluctuations, symptoms will also come and go. It is quite normal to vomit quite a lot one day and not feel any nausea the next. In addition, many women find that the symptoms of pregnancy become a lot less invasive towards the end of the first trimester, and even disappear altogether. Instead, new symptoms will pop up, and a baby bump will take the place of nausea.