It is common for expectant parents to feel a reduction or even a complete disappearance of pregnancy symptoms around the 15-week mark, which is the beginning of the mid-second trimester. This sudden shift often causes worry, but the sensation of “not feeling pregnant” is normal and expected. Early pregnancy symptoms like nausea and fatigue typically fade as the body moves past the intense hormonal changes of the first trimester. This transition into the second trimester, often called the “honeymoon period,” usually brings a noticeable increase in energy and a general feeling of well-being.
The Second Trimester Transition: The Dip in Symptoms
The abrupt fading of early symptoms is a direct result of a significant hormonal shift occurring inside the body. During the first trimester, the hormone human chorionic gonadotropin (hCG) is responsible for many of the most intense symptoms, including morning sickness and fatigue. The purpose of hCG is to signal the corpus luteum to continue producing progesterone until the placenta is ready to take over.
HCG levels typically peak between eight and twelve weeks, coinciding with the most severe nausea and vomiting. Around the start of the second trimester, hCG levels begin to decline and level off. This decrease in circulating hCG is the primary reason for the sudden relief from morning sickness and a general improvement in how a person feels.
A second major hormonal change involves progesterone, which supports the uterine lining to help the pregnancy thrive. The placenta, which is now fully developed, takes over the production of progesterone entirely from the corpus luteum around the tenth week of gestation. This transition, known as the luteal-placental shift, stabilizes energy levels compared to the chaotic fluctuations of the early weeks.
Although progesterone levels continue to rise, the body has adjusted to the hormone’s presence. This hormonal stabilization helps reduce the extreme fatigue and mood swings that characterize the first trimester. The feeling of being “not pregnant” is often simply the body settling into the reality of an established pregnancy.
Milestone Check: What the Baby is Doing at 15 Weeks
While maternal symptoms are receding, the fetus is undergoing rapid development and growth, even if the changes are not yet physically felt. By 15 weeks, the fetus is roughly the size of a large apple or orange, and its body is becoming more proportionate. The legs are growing longer than the arms, and the skeletal system is continuing its rapid development.
The fetus is highly active, moving, stretching, and turning within the amniotic fluid, though these movements are usually too subtle to be detected. Facial features are moving into their final positions, and the eyes can make small movements. The sense of hearing is developing, allowing the fetus to potentially hear the muffled sounds of the outside world, including the parent’s voice.
The uterus, which houses the growing fetus, is also undergoing significant change, rising out of the pelvis. This upward growth can sometimes cause round ligament pain, a quick, sharp pain on the side of the belly as the ligaments stretch. However, the baby remains small, and the amniotic fluid provides enough cushioning, that the first distinct feeling of movement, known as quickening, is rarely felt at this time.
Quickening is most commonly felt between 18 and 22 weeks, though some may feel it as early as 16 weeks. The movements are initially described as light flutters, bubbles, or gas, making them easy to miss or mistake for digestive activity. Therefore, the absence of fetal movement at 15 weeks is entirely consistent with a healthy pregnancy.
When Lack of Sensation Becomes a Concern
While the return to feeling more like oneself is a positive sign, it is natural to worry about the disappearance of symptoms. It is important to distinguish between the normal abatement of first-trimester discomforts and actual warning signs that necessitate medical attention. The normal dip in symptoms is gradual, whereas concerning changes are often sudden or accompanied by other physical signs.
A sudden loss of all pregnancy symptoms, especially if accompanied by heavy vaginal bleeding or severe abdominal cramping, should be immediately reported to a healthcare provider. Bleeding that is heavy enough to soak through a pad, or the passing of tissue, are signs that require prompt evaluation. Severe, persistent pain or cramping that is not relieved by rest or position change is also a reason to seek medical advice.
Other symptoms that warrant calling a doctor include a fever, severe vomiting that causes dehydration, or a sudden change in vaginal discharge, particularly if it smells unpleasant or changes color. The absence of quickening at 15 weeks is not a red flag; providers do not typically instruct monitoring fetal movement until much later in the second trimester. Being aware of true warning signs ensures that any potential issues are addressed quickly.