Describe the developmental changes that occur during human gestation. Fetal Development Month by Month OBJECTIVE: Describe the developmental changes that occur during human gestation.

First Month Germinal Stage (first 2 weeks after conception ) The egg is fertilized about week 2 and implanted in the uterus about week 3 Heart and lungs form

First Month

2 months **Embryonic Stage weeks 3-8 By the end of 8 weeks all essential organs form and are in their correct place **ORGANOGENESIS- The process of organ formation and growth Eyes and ears start to form Fingers and toes; wrists and ankles start to develop Measures about 1inch and weighs less than 1 ounce.

Two Months

END OF 1ST TRIMESTER 3 months Fetal Stage The developing baby is now called a Fetus-which lasts the duration of the pregnancy Soft nails appear on fingers and toes Heartbeat can be heard with a Doppler listening device Tooth buds develop END OF 1ST TRIMESTER (Weeks1-14)

4 Months (Week 14-18) 2nd trimester! The placenta is fully formed and carries all nutrients to the fetus, takes away wastes, and issues most of the hormones that maintain pregnancy Fetus is developing sucking and swallowing reflexes Kidneys are able to produce urine Eyebrows and eyelashes start to grow

4 months

Five Months A protective coating called vernix begins to form on fetus’ skin. Fetus sleeps and wakes on a regular cycle External sex organs are well-developed and might be seen on an ultrasound The fetus’ movements become more active and can be felt by the mother

Eyelids are formed and functioning- eyes can open for short periods of time Baby’s skin is covered in a soft downy hair called lanugo and a waxy white protective coating called vernix. With intensive care, a fetus might be able to survive if born during this month. Six Months

6 Months

Seven Months 3rd Trimester! (Weeks 27-40) The fetus can sense light and sound and will respond! The fetus many hiccup, producing rhythmic movements in the uterus The mother may start to produce and leak colostrum. Mother may also notice Braxton-Hicks contractions which are “practice” contractions that prepare the body for labor.

7 Months

Eight Months Rapid brain growth occurs at this time Bones continue to harden, but the skull remains soft and pliable for labor The fetus is rapidly storing body fat for warmth and energy The fetus has less room to move around so movements are less forceful on the mother

8 months

Nine Months 36-37 weeks is considered full term The lungs can function on their own The baby will drop to the birth position- usually head-down in the lower part of the abdomen- this is called lightening. Mother may have the urge to “nest” and want to clean and organize everything. Nine Months