During the fifth week of fetal development, a baby begins to develop its heart, muscles, bones, spinal cord and brain, according to WebMD. During this time, the umbilical cord connects to the baby to supply blood, oxygen and nutrition. The placenta and amniotic fluid begin to form in the womb.Continue Reading
Parents magazine explains the heart starts to divide into four chambers, and tiny cardiac muscle cells begin to contract. The yolk sac disappears as the umbilical cord attaches to the uterus. At five weeks, the embryo is the size of an apple seed, and it looks like a tadpole with a tail. Pregnancy symptoms such as morning sickness, tender breasts, fatigue and more frequent urination may appear at this stage.
Baby Center states that three distinct layers begin to separate into various organs. The top layer, or ectoderm, contains the neural tube that forms the spinal cord, brain, backbone and nerves. The middle layer, or mesoderm, contains the heart that beings to pump blood at five weeks. The endoderm, or innermost layer of tissue, forms other internal organs later in the pregnancy.
During the sixth week of fetal development, limbs start to form, and the eyes begin to distinguish themselves on the surface. When a doctor does an ultrasound, a heartbeat may be heard at this time, according to WebMD.Learn more about Pregnancy
A woman with an average 28 day menstrual cycle is most likely to get pregnant between days 12 and 15 of her menstrual cycle according to WebMD. The exact number of days that ovulation occurs after a woman's period ends varies based on the woman's menstrual cycle. If a woman's period lasts 5 days, this would be 7 to 10 days after her period has ended.Full Answer >
Important milestones in fetal development occur in the fifth, 12th and 24th weeks. The fifth week is the start of the embryonic period. In the 12th week, the fetus starts to move, and in the 24th week, the baby responds to external sounds, explains WebMD.Full Answer >
Fetal development begins at conception and ends 37 to 41 weeks later with the birth of a full-term baby, according to MedlinePlus. This time period, called gestation, is measured in weeks. Gestational age is measured from the first day of the mother's last menstrual cycle.Full Answer >
The exact date of conception is too difficult for anyone to find out, but doctors use the first day of the last menstrual cycle to determine the age of the fetus, according to WebMD. When a woman has regular periods, she can determine how far along in the pregnancy she is by counting the time from the first day of her most previous menstrual cycle.Full Answer >