Everyone asks how big their baby is. So, in a nut shell, I will attempt some similes.
First of all, your baby isn't called a fetus until the third month counting from the first day of the last menstrual period. Then it is an embryo. The first day of the last period is the official day one of the pregnancy although we all know that conception happens about fourteen days after that first day of the last period. The sex of the baby is determined at conception although not well visualized until about sixteen weeks on sonogram.
First Month, very small shrimp, about fifty centimeters. Many vital organs are beginning to be differentiated and there is a sac of fluid but the placenta and cord are still forming.
Second Month, feeder goldfish, one ounce, one inch. Big, big head to accommodate rapidly growing brain. Limbs including fingers and toes are growing. Facial features moving into recognizable position.
Third Month, four inches about the size of Mom's index finger, still about an ounce. Detectable heat tones, moving a lot, maybe hair, nails.
Fourth Month, six inches long, baby banana, one third of a pound. Teeth, functioning hands. Swallowing amniotic fluid. Can hear you sing.
Fifth month, you are definitely visibly pregnant to the world. Feeling movement at times, probably not everyday. Your one pounder is ten inches long and may be a thumb sucker!! Spring- time Robin or Blue Jay
Sixth Month, Fetal characteristics are baby-like. Length of a ruler and skinny at about eighteen ounces. Eyes are opening and moving a lot. Rhythmic beats are the hiccups.
Seventh Month, you are gaining weight and it's all baby packing it on up to two or two and one-half pounds. Fourteen to fifteen inches. A football. Breathing movements are happening and the bony spine is forming. Can see light, smell and taste. Hearing is very acute.
Eighth Month, putting on weight and wrinkles are smoothing out. Seventeen inches and gaining on five pounds. A real baby doll!! Moving towards head first. All vital organs are good to go but the lungs; they come last.
Ninth Month, BIG baby makes Mom ready to get it out. Head down and too fat to do much but the twist. When lungs are mature, baby is term, weighing on average seven and one- half pounds, about twenty inches. Covered in vernix which is like Crisco to protect skin from all that water and actually developing sleep patterns that will continue in infancy. Watch out!