Share This Link

Subcutaneous fat does not begin to accumulate until the third trimester. Fat deposition accelerates after week 28 and continues until term, helping with thermoregulation and energy storage postpartum.

Lanugo begins to form around weeks 13–16 and is a normal early second-trimester feature. However, it is not the only structure that forms at this time, making this answer incomplete.

Vernix caseosa begins to develop alongside lanugo in the early second trimester. It alone does not represent the full scope of what occurs during this period, making this option incomplete.

The rapid growth spurt occurs during the second trimester but is not related to maternal perception of fetal movement. Fetal length increases from approximately 9 cm at week 12 to 25 cm by week 20, but this process is silent to maternal sensation.

Braxton Hicks contractions are irregular, painless uterine contractions that begin in the second trimester but typically intensify in the third. They are not perceived as fetal movement and are unrelated to the neurologic activity of the fetus.

Engagement of the fetal head, also called lightening, occurs near term when the presenting part descends into the pelvic inlet. This mechanical process is different from fetal movement and occurs later, usually after 36 weeks in primigravida.

Fetal movement at weeks 12–14 is minimal and not strong enough to be perceived by the mother. Although spontaneous movements occur by week 7–8 on ultrasound, they are too subtle for maternal detection this early.

While fetal movements are definitely present by weeks 21–24, this is later than the expected window for initial perception in primigravida mothers. Most first-time mothers have already reported quickening by this stage.

Weeks 25–28 are well beyond the expected time of initial fetal movement perception. Movements during this stage are more forceful and regular but should not be the first perceived movements in a normal pregnancy.

Non-stress test (NST) is used in the third trimester, typically after 28 weeks, to assess fetal heart rate patterns in response to movement. It evaluates fetal well-being in high-risk pregnancies but does not assess fetal anatomy or development in the second trimester.

Amniocentesis can be performed in the second trimester (usually after 15 weeks), but it is not a routine assessment of fetal development. It is an invasive diagnostic test used for genetic testing, lung maturity, or infection evaluation when indicated.

Biophysical profile is done later in pregnancy, typically after 28 weeks, to assess fetal well-being using ultrasound and NST. It evaluates fetal breathing, tone, movement, and amniotic fluid but is not used for developmental assessment during the second trimester.