Your fetus now resembles a well-proportioned baby, although they are still quite thin, as baby fat development hasn't fully begun. They currently have only about 1% body fat, which will increase significantly in the coming weeks, helping them to regulate their body temperature after birth. Fingernails completely cover the fingertips and continue to grow. Your baby weighs about 350-425 grams (12.3-15 ounces) and measures around 19 cm (7.5 inches) crown to rump. By the end of the fifth month, your baby will establish a more regular sleep-wake cycle. They can even furrow their brow as if concentrating! Their eyelids are fully developed but remain shut until around 28 weeks. Arms and legs have reached their final proportions (though not their final size) and are being exercised extensively within the womb. The baby's eyelashes and eyebrows are growing, and their total length (head to toe) is approximately 10 inches