The term developing ovum is used for the first seven to ten days after conception, i.e. until the implementation occurs. It is called ‘embryo’ from one week to the end of the second month, and later it is called ' fetus (or foetus, or fśtus) '. It becomes an infant when it is completely 'born.
In a pregnancy, there can be multiple gestations (for example, in the case of twins, or triplets). Human pregnancy is the most studied of all mammalian pregnancies. Human pregnancy lasts approximately 9 months between the time of the last menstrual cycle and childbirth (38 weeks from fertilisation). A pregnancy is considered to have reached term between 37 and 43 weeks from the beginning of the last menstruation. Babies born before the 37 week mark are considered premature, while babies born after the 43 week mark are considered post-mature.
Amniotic fluid is a liquid that surrounds a fetus during pregnancy. Any disruptions to the amniotic fluid, such as a bacterial infection, could potentially be dangerous to both the mother and baby.Woman who are pregnant or considering becoming pregnant should speak with their dental and healthcare professionals about their oral health during pregnancy.
Do not smoke during pregnancy, because vitamins won't help to negate smoking's effects.Women who smoke and take vitamins do not really minimize the risk of pre-term birth, low-birth weight babies and babies who were smaller than average for their gestational age, all conditions that are associated with smoking.
Alcohol use during pregnancy is a leading preventable cause of birth defects and developmental disabilities in the United States, according to the Centers for Disease Control and Prevention. Fetal Alcohol Spectrum Disorder -- which includes a range of cognitive, emotional and behavioral problems -- may be present in as many as one of every 100 births.
End of first month : Length one cm; weight two and half g. The eyes are seen as two dark spots, and the mouth as a cleft.
End of second months : Length tour cm; weight ten g. The hands and feet are webbed. The placenta begins to form. The anus is seen as a dark spot.
End of third months : Length nine cm; weight thirty g. The eyes are closed and the pupillary membrane appears. Nails appear and the neck is formed
End of fourth months : Length 16cm; weight 120 g. Sex can be recognized. Lanugo hair is seen on the body. Convolutions begin to develop in brain. Meconium is found in the duodenum.
End of fifth months: Length 25 cm; weight 400 g. Nails are distinct and soft. Light hair appears on head. Skin ts covered with vernix caseosa. Meconium is seen at the beginning of the large intestine.
End of sixth month : Length 30 cm; weight 700 g. Eyebrows and eyelashes appear. Skin is red and wrinkled and subcutaneous fat begins to be deposited .The testes are seen close to the kidneys.
End of seventh months : Length 35 cm; crown-rump length 23 cm; foot length 8 cm; weight 900 to 1200 g. Nails are thick. Eyelids open and pupillary membrane disappears. Skin is dusky-red, thick and fibrous. Meconium is found in the entire large intestine. Testes are found at external inguinal ring. Gall-bladder contains bile and caecum is seen in the right iliac fossa.
End of eighth months : Length 40 cm; weight one and half to two kg. Nails reach the tips of fingers. Scalp hair is thicker. Skin is not wrinkled.' Left testis is present in the scrotum. Placenta weighs 500 g,
End of ninth months : Length 45 cm; weight two and half to three kg. Scalp hair is dark and 4 cm. long. Meconium is seen at the end of large intestine. Scrotum is wrinkled and contains both testes. Placenta weighs 500 g. Ossification centers are usually present in the lower end of the femur, in the cuboid and capitate bones.
End of tenth months : (full term child ) : Length 50 to 53 cm; crown-rump length 30 to 33 cm weight 2.5 to 5 kg; average about 3.4 kg. The length is much less variable than the weight. The male infant weighs about 100 g. more than the female. The circumference of the head is 33 to 36 cm. At full term the head of a child is nearly one-fourth of the whole length of the body. The surface of the brain shows convolutions, and the grey matter begins to form. The scalp hair is dark, 3 to 5 cm long. The face is not wrinkled. Lanugo is absent except on the shoulders. The skin is pale and covered with vernix caseosa.
The nails project beyond the end of fingers but reach only the tip of the toes. The cartilages have formed in the nose and ears. The testes are present in the scrotum; vulva is closed and labia minora are covered by fully developed labia majora. The rectum contains dark brownish, green or black meconium. The placenta is 22 cm. in diameter, one-and-half cm. thick at the centre, and weighs about 500 gm. The umbilicus is situated midway between pubis and xiphoid cartilage. The umbilical cord is 50 to 55 cm. long and one 'cm. thick.
Recent advances in knowledge about the impact of early life events on the neonatal transition, infant development, cognitive development and life-long sequelae means that a broader characterization of the outcome of pregnancy is needed rather than birth size alone.
The issue of concern thus became the need to optimize fetal development, a concept which embraces a broad set of considerations including the health of the mother before and during pregnancy; the length of gestation; the size of the newborn for his or her gestational age; whether fetal development has been disrupted; and whether the infant is exposed to a nutritional, physical and emotional environment that maximizes its potential for growth, development and a healthy life. Accordingly, birth is seen as a single event in a continuum of development and change that starts at or before conception and extends into adulthood, and in which earlier experience can have effects on subsequent function throughout all stages of the life-cycle.
Due to technological advances in the last decade of the 20th century, it is now medically possible to remove one or more cells from the blastula (a preembryo) prior to its implantation in the uterus. Fertilization occurs in vitro, by taking the husband's semen and allowing it to fertilize the ovum of the wife, like any in vitro fertilization project. When fertilization occurs, the zygote is allowed to grow to the blastula or morula stage (a few days after fertilization).
If there is a possibility of genetic disease or chromosomal abnormality (e.g. triosomy 13, 18 or 21), one or more cells are taken from the blastula and examined for the suspected defect. If the blastula is shown to bear the defective gene or chromosome, it is discarded and another tested. Only blastulae free from genetic or chromosomal defects are reimplanted.
A disadvantage of this technology is the low reimplantation success rate. Best practice achieved to date has so far produced a pregnancy success rate of 30%, with successful births numbering approximately 15% of total attempts. The advantage of the method is that it avoids abortion.
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