fetal development
...an be identified in the blood or urine 8-9 days after ovulation. Home pregnancy tests can be inaccurate if taken too soon after conception, and if done after the 12th week, false negatives may occur due to low levels of hCG. Radioimmunoassay (RIA) blood tests are the most accurate since they can detect hCG within a few days after conception and can monitor pregnancies that may be in jeopardy. Most physicians calculate a due date from the first day of the last menstrual period rather than the day of ovulation or fertilization. The standard for due date calculation is called the Naegeles Rule: subtract 3 months from the 1st day of the last period and add 15 days for a single birth and 10 days for multiple births. Sex Selection: Myth and Modern Methods. Although more males are conceived, a higher percentage of male fetuses are spontaneously aborted or die before birth than female fetuses. Historically, many myths have existed related to choosing the sex of a child such as tying up the right or left testicle. Some people want to choose the sex of their child to reduce the chance of having a child with a genetic condition that affects one sex more often. Although there are no 100% methods of sex selection right now, there are some expensive methods available through artificial insemination. During the 16th or 17th week of pregnancy, an amniocentesis can be performed to determine sex and heath issues. A small sample of amniotic fluid is drawn out of the uterus through a needle inserted in the abdomen. 1st Month, the fertilized egg multiplies into many cells. Some cells develop into the embryo and some cells develop into the placenta. About 8 days after fertilization the embryo will attach to the uterine lining. The embryo is only 1/8 inch long by the end of this first month, but has already begun to develop the early stages of a heart, liver and digestive system. Tiny buds form which will later develop into arms and legs. 2nd Month, all of the major organs are forming. The embryo's heart is pumping blood. The head is relatively large compared to the rest of the body and brain development is well underway. The eyes are distinctly visible. The hands and feet look like little scalloped paddles at this early stage. By the end of the second month the embryo is a little over an inch long. 3rd Month, the embryo is now called a fetus. Kidneys are producing urine which the fetus excretes into the amniotic fluid. The amniotic fluid is cleansed via the umbilical cord then out through the mother. Bone is replacing cartilage, and muscles are developing. Fingers, toes and eyelids have formed. Testicles have formed in boys and ovaries in girls. By the end of the third month the fetus is about 2 1/2 - 3 inches long and weighs about 1/2 ounce. 4th Month, all organs have developed. The fetus just needs time to grow and mature. Beneath the gums, teeth are forming. Fine hair begins to grow all over the body. Fingernails form. The baby sucks and swallows. The baby actively kicks its legs and moves its arms, but not with enough strength for the mother to be able to feel the movement. By the end of the fourth month the baby is 5-6 inches long and weighs 3-4 ounces. The uterus is now about four inches in diameter and the mothers tummy may show a slight bulge. 5th Month, the baby has been busy growing and is now big enough for the mother to feel her fetus moving about inside of her. A thumb may find its way to the baby's mouth for sucking. Hair is growing on the head. The baby can hear muffled sounds. A protective fatty substance called vernix covers the baby's skin. By the end of the fifth month the baby is 8-10 inches long and weighs 8-12 ounces. Still under one pound. 6th Month, finger prints are visible. The eyelids will part for the first time this month and the eyes will open. The lungs begin to mature, getting ready for a healthy first breath. Bones are hardening as calcium deposits. The baby's movements become more vigorous. Until now, no body fat has accumulated, that occurs mostly in the third trimester. The baby has reached a length of nearly 11-12 inches and weighs about 1 1/2 pounds. 7th Month, the brain is enlarging. Body fat is accumulating. There is less room for the baby to move around now. Taste buds are forming and the baby's senses are becoming more acute. The baby hears the voices of those nearby. By the end of the seventh month the baby could have a good chance of survival if born prematurely, but would require intensive medical care. The length has reached about 13-15 inches, and the baby now weighs close to 2 1/2 to 3 pounds. 8th Month, the lungs are maturing further. Continued rapid growth is occurring. Kicks may be visible by watching the mothers abdomen move. The baby occasionally gets the hiccups. If delivered prematurely, the baby has an excellent chance of survival. The baby is about 16-18 inches long now and weighs 4-5 pounds. 9th Month, the baby deposits body fat at a rate of nearly 1/2 ounce per day. The lungs are mature. In these tight quarters the baby may seem a little less active. The normal position for the baby to be in as it prepares for birth is head down and facing the mothers back. The head engages in mother's pelvis. Mother carries the baby lower, making it easier for the mother to breath. At birth the average baby weighs 7-1/2 pounds, but weight can vary between 6 to 9 pounds. Average length is 17 to 22 inches. Problems in pregnancy. Ectopic Pregnancies In an ectopic pregnancy the zygote implants outside of the uterus, with 97% implanting in the Fallopian tube (tubal pregnancies) and the remaining 3% occurring in the abdomen, cervix, or ovaries. Rates of ectopic pregnancies have been increasing due to increases in the incidence of pelvic inflammatory disease caused by chlamydia. It is very dangerous and is the primary cause of maternal mortality in the first trimester of pregnancy, with 30-40 women dying each year in the U.S. Smoking has been linked to ectopic pregnan...