During the seventh month of pregnancy, which encompasses weeks 25 to 28, the developing fetus undergoes significant growth and development. At this stage, the baby is nearing its final size and shape before birth, although there is still considerable maturation to be achieved. Here’s an in-depth look at the physical appearance and development of the fetus during the seventh month:
General Appearance
By the seventh month, the fetus has grown considerably in size. On average, the baby is about 12 to 14 inches (30 to 35 centimeters) in length from head to toe and weighs approximately 2 to 4 pounds (900 grams to 1.8 kilograms). The baby’s body proportions are becoming more balanced, with the head, torso, and limbs in more proportionate alignment compared to earlier stages.
Skin and Subcutaneous Fat
The fetus’s skin, which was previously translucent and wrinkled, is now becoming more opaque and less wrinkled as it starts to accumulate subcutaneous fat. This fat layer is crucial for thermal regulation after birth and provides the baby with energy reserves. The skin color is also beginning to change, with the pigmentation becoming more pronounced, although it may still appear reddish due to the thinness of the skin and visible blood vessels.
Features and Hair
The facial features of the fetus are becoming more defined and recognizable. The eyes are fully formed and have developed the capability to open and close, though they remain closed most of the time. Eyebrows and eyelashes are present, and fine, downy hair known as lanugo covers the body. Lanugo is gradually being shed and will mostly disappear before birth. The hair on the scalp is also becoming more visible, and its texture and color may start to develop more distinctly, though this can vary significantly among individuals.
Nervous System Development
The fetal nervous system is maturing rapidly during this period. The brain continues to develop, with the formation of more complex brain structures and increased activity. The baby’s movements are becoming more coordinated, and there may be noticeable patterns of sleep and wakefulness. Reflexes such as sucking and grasping are becoming more refined, and the baby can respond to external stimuli like sounds and light.
Musculoskeletal Development
The bones of the fetus are hardening, though they are still relatively soft compared to those of a fully grown baby. This ossification process is crucial for preparing the baby’s body for birth and postnatal life. The baby’s movements are becoming more pronounced and may be felt more strongly by the mother. Kicking, rolling, and stretching are common as the fetus adjusts to its growing space and strengthens its muscles.
Respiratory and Cardiovascular Systems
The respiratory system is developing rapidly, with the lungs producing surfactant, a substance that will help keep the air sacs in the lungs from collapsing after birth. Although the fetus is not breathing air, it practices breathing movements by inhaling and exhaling amniotic fluid. The cardiovascular system is also becoming more efficient, with the heart beating strongly and pumping blood effectively throughout the fetus’s body.
Immune System Development
The fetus’s immune system is maturing, with the production of white blood cells increasing. Although the fetus relies on antibodies transferred from the mother for protection against infections in the early months after birth, its own immune system is preparing to take over.
Summary
In summary, by the seventh month of pregnancy, the fetus is well into its journey toward being fully developed. It has grown significantly in size, with a more proportionate body and increasingly defined features. The skin is becoming less transparent and more pigmented, while subcutaneous fat accumulates. The nervous and musculoskeletal systems are maturing, and the respiratory and cardiovascular systems are becoming more functional. The overall appearance of the fetus reflects its ongoing development and preparation for life outside the womb.