3. 16-18 weeks foetus

Between 16 and 18 weeks, the fetus grows rapidly, reaching about 5.5 inches and 7 ounces, with recognizable facial features, working limbs, and developing hearing. The skin is translucent, showing blood vessels, and covered in fine hair (lanugo). At 18 weeks, they may start hearing sounds, and gender is often visible on ultrasound. 

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Key Developmental Milestones (16-18 Weeks):

• Physical Movement: The fetus is increasingly active, flipping and rolling, and limbs are fully developed.
• Sensory & Facial Features: Ears are moving into place, eyes can detect light, and they can make faces.
• Internal Systems: Bones are beginning to harden (ossify), and the nervous system is developing.

• Size: By 18 weeks, the fetus is roughly the size of a sweet potato or artichoke. 

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Physical Changes for the Mother:

• Movement: Many parents start to feel "quickening" or light flutters/bubbles.
• Symptoms: Increased energy, but potential for back pain, nosebleeds, and skin changes (melasma).
• Growth: The uterus grows to about 8.5 ounces