Pregnancy Week by Week

Pregnancy is categorized in three different stages such as: first, second and third trimesters. First trimester covers 1 to 14 weeks, second covers 15 to 26 weeks and third involves 27 to 40 weeks.

Week 1 & 2 is the stage wherein the body prepares ovulation and within this phase the egg gets fertilized by the sperm.

Week 3 fertilized egg moves down the fallopian tubes. Implantation starts and cell ball becomes the embryo.

Week 4 Amniotic sac and cavity develops, yoke sac appears. Placenta begins to form. By twenty-seventh day mother starts feeling morning nausea.

Week 5 is the time to develop primitive streak, cells develop into three layers: endoderm; mesoderm and ectoderm.

Week 6 wherein baby’s heart begins beating, aorta starts forming by 40th day and by mid week organs begin forming.

Week 7 baby grows doubles in size, eye-lenses and tongue form. The legs and arms develop into paddles and jaws become visible too.

Week 8 cerebellum–part of brain responsible for muscular movements, hand, foot plates, elbow and wrist areas begin to form.

Week 9 baby starts forming cartilage and bones, ovaries develop into sex organs helping to ascertain whether boy or girl.

Week 10 the embryo becomes baby now.

Week 11 the morning nausea disappears and appetite improves and baby’s body starts straightening. The baby’s sex organs develop.

Week 12 baby starts developing finger nails over next three weeks, opening and closing its mouth.

Week 13 vocal chords develop in the larynx and intestines moving from umbilical cord into abdomen.

Week 14 noticeable change takes place around nipples, baby’s heart beats could be heard with Doppler.

Week 15 baby’s neck is defined, head properly rests on the neck, and baby turns head, opens mouth, starts kicking or turns its feet.

Week 16 baby’s toe-nails, muscles grow stronger, neck and head grow straighter.

Week 17 baby works on more reflexes – blinking, sucking and swallowing.

Week 18 baby’s eyes and ears are now placed appropriately.

Week 19 creamy fluid covers the baby’s body and vernix coseosa starts forming.

Week 20 almost all vital developments take place by this week surpassing the danger phase of the initial three months.

Week 21 the baby replaces the amniotic fluid every three hours.

Week 22 the taste starts moving from pelvic area into the scrotum if baby is boy.

Week 23 the middle ear bones harden enabling conduction of sound. Baby gains weight.

Week 24 baby’s skin wrinkles but gets smoothened as fat is deposited.

Week 25 baby’s skin turns reddish pink following capillaries development. Nostrils open up.

Week 26 muscular breathing starts.

Week 27 since baby grows stronger the bumping and thumping becomes stronger too.

Week 28 the eyelids open-up, muscle tone improves and lungs start breathing air. By this time baby’s chances of premature delivery brightens.

Week 29 eye lashes are fully grown and baby's eyes are now sensitive to dark and light.

Week 30 baby starts storing essential nutrients ingested by mother.

Week 31 the growth starts slowing down as the internal organs continue maturing.

Week 32 all the five senses now registers with the baby and its iris starts reacting to light.

Week 33 baby may start sucking its fingers, chances of constipation rises in mother as uterus pressurizes bowels more.

Week 34 the eyes look blue as eye pigmentation is not fully developed yet. The baby starts developing immune system.

Week 35 the baby shifts into pelvis head-down position.

Week 36 Dimples on elbow and knees and creases on the neck area form up. Fat helps maintaining baby's body temperature.

Week 37 nearly 85 percent babies are born within 2 weeks of actual due date thus mother should now be alert for labor now onwards.

Week 38 meconium starts gathering in the intestines.

Week 39 the baby settles in the pelvis making the mother feel off-balance due to shifting of center of gravity.

Week 40 this is the final week and mother may deliver the baby anytime.