First Trimester | 3D Animated Pregnancy Guide
Congratulations – you’re about to be a
mother! Becoming a parent is an exciting and rewarding
experience, but it can also feel overwhelming sometimes, and you likely have lots of questions. I hope this series of videos will be a helpful
companion throughout your pregnancy. Pregnancy begins when a man’s sperm fertilizes
a woman’s egg. Since you don’t always know when fertilization
occurs, doctors calculate pregnancy based on the first day of your last menstrual period.
Your egg may have been fertilized just two
weeks ago, but because your last period was four weeks ago, you’re officially four weeks
pregnant at the time of your missed period! Your doctor will count forward 40 weeks from
your previous menstrual period to estimate your due date. If you have an ultrasound early in your pregnancy,
your doctor may measure the baby to determine your due date instead. In the first month of your
pregnancy, a water-tight sac forms around the embryo, gradually filling with fluid. This is called the amniotic sac, which helps
cushion the growing embryo. There’s also another type of sac called
the yolk sac. The yolk sac will provide nutrients to the
embryo while the placenta is developing. The fetal nervous system is one of the very
first systems to develop.
At about week five of pregnancy, the neural
plate folds onto itself to form the neural tube. The neural tube is a hollow structure of tissue
which later develops into the brain and spinal cord. In the same week, the preliminary structures that will become your baby's
heart begin spontaneously pulsing. Blood cells are taking shape, and circulation
will begin. The tiny "heart" tube now beats 100 times
a minute. The fetus is about the size of a grain of
rice.
Facial features continue to develop. Each ear begins as a little fold of skin on
the sides of the head, and tiny buds that eventually grow into arms and legs form. Bone also starts to replace cartilage. By the end of the second month, the fetus
is about the size of a raspberry. By the end of the third month, the fetus is
fully formed, and all organs and limbs are present. The fetus is now about the size of a plum
and fills your entire uterus. Since the most critical development has taken place, your chance of
miscarriage drops considerably after three months. While your first sign of pregnancy might have
been a missed period, you can expect several other physical changes in the coming weeks
as your body adjusts to the hormonal changes of pregnancy. Rising levels of hCG may be responsible for
the waves of nausea and vomiting that are known as morning sickness. Despite its name, morning sickness can occur
any time of day. A pregnant person may also feel more tired
than usual during the first trimester, a symptom linked with rising levels
of the hormone progesterone, which increases sleepiness.
Progesterone also acts as a muscle relaxant,
preventing your uterus from contracting until the onset of labor. But those same muscle-relaxing properties
can also cause heartburn and constipation, as it slows down your digestive tract. And finally, progesterone is associated with that classic irritability
present in the premenstrual period — and because your progesterone levels
stay elevated during your pregnancy, mood swings can be a side effect. Meanwhile, estrogen helps to maintain the
endometrial lining, which is vital for the baby’s development. Estrogen is believed to promote an increase
in blood flow, which is important for nourishing the baby, but that extra blood flow has the
side effect of making your breasts achy and tender. The increased blood flow can also cause you
to head to the bathroom more often. As your kidneys process the extra fluids and
your uterus puts pressure on your bladder, you might feel the urgent and frequent need
to pee. Fortunately, increased blood flow has at least
one potential benefit — it may be the reason for your skin’s healthy pregnancy glow.
Most pregnant women gain between 10kg and
12.5kg and put on most of the weight after week 20. Much of the extra weight is due to your baby
growing, but your body will also store fat to turn into breast milk after your baby is
born. Thank you for watching this video. If you’d like to know how fertilization
or breastfeeding works, please watch my next video.
