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The parts of the fetal brain that control movement will not fully form until late in the second trimester, and the first part of the third trimester. [7] Control of movement is limited at birth, and purposeful voluntary movements develop during the long period up until puberty. [8]
Quickening indicates the start of fetal movements, usually felt 14–26 weeks after conception, or between the fourth and sixth month. [ 5 ] [ 6 ] A woman pregnant for the first time (i.e., a primigravida woman) typically feels fetal movements at about 20–21 weeks, whereas a woman who has given birth at least once will typically feel ...
The fetus is considered full-term between weeks 37 and 40 when it is sufficiently developed for life outside the uterus. [14] [15] It may be 48 to 53 cm (19 to 21 in) in length when born. Control of movement is limited at birth, and purposeful voluntary movements continue to develop until puberty. [16] [17]
Genitourinary Changes in Pregnancy. Progesterone causes many changes to the genitourinary system. A pregnant woman may experience an increase in the size of the kidneys and ureter due to the increase blood volume and vasculature. Later in pregnancy, the woman might develop physiological hydronephrosis and hydroureter, which are normal. [33]
Embryonic age: Weeks nr 34–38. 33–37 weeks old. The fetus is considered full-term at the end of the 39th week of gestational age. It may be 48 to 53 cm (19 to 21 in) in length. The lanugo is gone except on the upper arms and shoulders. Fingernails extend beyond fingertips. Small breast buds are present on both sexes.
During vaginal birth, the newborn's chest is compressed by the birth canal. Upon delivery, negative pressure allows air into the lungs. The first cries of the infant allow for alveoli expansion and absorption of fetal lung fluid. Temperature changes and other sensory stimulation contributes to respiratory function as well.
According to the WHO, a preterm birth is defined as "babies born alive before 37 weeks of pregnancy are completed." [20] According to this classification, there are three sub-categories of preterm birth, based on gestational age: extremely preterm (fewer than 28 weeks), very preterm (28 to 32 weeks), moderate to late preterm (32 to 37 weeks). [20]
The breasts change during pregnancy to prepare for lactation, and more changes occur immediately after the birth. Progesterone is the hormone that influences the growth of breast tissue before the birth. Afterwards, the endocrine system shifts from producing hormones that prevent lactation to ones that trigger milk production. [3]