Pregnancy Week By Week

Pregnancy week by week period, starts about 3-4 weeks before you’re pregnant — a full-term pregnancy usually totals about 40 weeks from Last menstruation period.

Many women don’t remember exactly when they started their last menstrual period, it doesn’t matter. The exact observation to find out gestational age early in pregnancy is with an ultrasound.

What happens in the development of pregnancy in the first two weeks?

The first 2 weeks of your menstrual cycle period 2 weeks later, the most mature egg is released from your ovary this is the ovulation period. Ovulation may happen earlier or later, depending on the length of your menstrual cycle.  The menstrual cycle period lasts 28 days on average

After that, your egg travels down your fallopian tube toward your uterus. If the egg meets up with sperm, they combine during the fertilization period. Fertilization, occur when you have unprotected vaginal sex during the 6 days leading up to (including the day of “ovulation”).

What happens in the development of pregnancy in the first 3-4 weeks?

The fertilized egg moves down your fallopian tube and divides into more and more cells. It reaches your uterus about 3–4 days after fertilization. The dividing cells then form a ball that floats around in the uterus for about 2–3 days.

Pregnancy begins when the ball of cells attaches to the lining of your uterus. This period’s name is implantation, and usually starts about 6 days after fertilization and takes about 3–4 days to be complete.

Pregnancy doesn’t always happen, even if an egg is fertilized by a sperm. Up to half of all fertilized eggs pass out of your body when you get your period before implantation is complete.

What occurs during 5 – 6 weeks of pregnancy period?

  • The embryo is less than 4–5 mm long.
  • A circulatory system and very basic beating heart develop.
  • Buds for arms and legs evolve.
  • The neural tube begins forming. The neural tube will later
  • form the brain, spinal cord, and major nerves.
  • The bud of a tail develops.
  • The umbilical cord begins evolving.

What happens during weeks 7 – 8?

  • The embryo is 7–14 mm long.
  • The heart has formed.
  • Webbed fingers and toes develop.
  • The arms bend at the elbows.
  • External ears, eyes, eyelids, liver, and upper lip begin forming. 
  • Organs are the same — neither male nor female — in all embryos until the 7th or 8th week. If a gene triggers the development of testes, the embryo develops as a biological male. If there isn’t a trigger, the embryo develops ovaries and becomes biologically female.

What comes into existence during weeks 9 – 10?

  • The embryo forms into a fetus after 10 weeks. It’s 21–40 mm long. The tail disappears. Fingers and toes grow longer. The umbilical cord connects the abdomen of the fetus to the placenta.  The placenta is attached to the wall of the uterus and it absorbs nutrients from the bloodstream. The cord carries nutrients and oxygen to the fetus and takes waste away from the fetus.
  • Miscarriage
  • Most early pregnancy forfeit — miscarriage — happens in the first trimester. About 15 percent of pregnancies end in miscarriage during the first trimester.

What happens during week 13 – 14?

  • The fetus has a CRL of about 8 cm.
  • The biological sex of the fetus can sometimes be seen by looking at external sex organs on an ultrasound.
  •  Hair begins to grow.
  • The prostate gland begins developing in biologically male
  • fetuses.
  • Ovaries move down from the abdomen to the pelvic area in biologically female fetuses.

What happens during week 15 – 16?

  • The fetus has a CRL of about 12 cm.
  • Hundreds of thousands of eggs form in the ovaries of
  • biologically female fetuses.
  • The fetus has a CRL of about 14–15 cm.

What happens during week 19 – 20?

The fetus has a CRL of about 16 cm. Lanugo — a fine downy hair — covers the body.  The skin is also covered with vernix caseosa, a greasy material that protects the skin. A uterus forms in a biologically female fetus.

What happens during week 21 – 22?

  • The fetus has a CRL of about 18–19 cm.
  • Bone substance starts making blood cells.
  • Taste buds begin to form.

What happens during week 23 – 24?

The fetus has a CRL of about 20 cm.

Eyebrows and eyelashes usually develop between weeks 23 and 26.

What happens during week 25 – 26?

The fetus has a CRL of about 23 cm.

The fetus develops more and more fat from now until the end of pregnancy. 

What happens during week 27 – 28?

The fetus has a CRL of about 25 cm.

Eyelids are usually fused until about 28 weeks.

What happens during week 29 – 30?

The fetus has a CRL of about 27 cm.

Testes usually proceeding down into the scrotum from theabdomen between weeks 30 and 34 in a biologically male fetus. This is usually complete by 40 weeks.

What happens during week 31 – 32?

The fetus has a CRL of about 11 inches (28 cm).

Lanugo starts falling off. What happens during week 33 – 34?

  • The fetus has a CRL of about 30 cm.
  • The eyes have developed enough for pupils to constrict and dilate when exposed to light.
  • Lanugo is nearly all gone.

What occurs during week 35 – 36?

The fetus has a CRL of about 32 cm.

The fetus is considerably fatter, and the skin is no longer wrinkled.

What happens during week 37 – 38?

The fetus has a CRL of about 34–36 cm.

The fetus has a firm grasp.

What happens during week 39 – 40?

  • Women will probably give birth around this time.
  • The average newborn baby weighs 3-3,6 kg and is between 46–56 cm long with legs extended.
  • Almost all of the vernix and lanugo is gone.
  • It’s common for newborns to have some lanugo that disappears over the first few months of life.