Stages and features of pregnancy

Pregnancy
The period from conception to birth.It begins with conception,the fertilization of an ovum (egg)by a sperm and the subsequent implantation of fertilized egg.The egg developed into the placenta.and embryo,and later into the fetus.most fertilized egg implant into the uterus.However , Occasionally, an egg implant into an abnormal site such as fallopian tube resulting in an ectopic pregnancy,which may develop into an emergency situation.
As mother body adjusts to pregnancy,she will see a number of physical changes taking place her menstruation period cease and breasts become tender and full. eating habits may change.moodiness or fatigue may also occur at the onset of pregnancy.for mostly by the end of third month, mother will feel better and both will feel the joy of there very own pregnancy.

Stages and features of pregnancy

First trimester(0 to12 weeks)

The first sign if pregnancy is usually the absence of menstrual period,though some woman have breakthrough bleeding.The breasts starts to swell and may become tender as mammary glands develop to prepare for barest feeding.the nipple start to enlarge and the veins over the surface of the breasts become more prominent.Supportive bra should be worn.Nausea and vomiting are common,are ofter worse in the morning,and usually persist for six to eight weeks.Urine is passed more frequently and there is often a creamy white discharge from the vagina.Many woman feel unusually tired during the early weeks.Some notice a metallic taste in the mouth or a craving for certain foods.weight begin to increase.

Second trimester(13 to28weeks)
From 16 weeks,the enlarging uterus is easily felt and the woman begins to look noticeably pregnant.the nipples enlarge and darken.and the skin pigmentation may be deepen.Some women may feel warm and flushed.Appetite tends to increase and weight rises rapidly.Facial features tend to become heavier.by 22 weeks (usually 18 to 20 weeks) most pregnant women have felt the baby moving around (some times called quickening)
during the second trimester ,nausea and frequency of urination diminish,and the woman may feel generally better and more energetic than during early weeks.the heart rate increases, as does the volume of blood pumped by the heart,to allow fetus the develop properly.These changes put an extra strain on the heart of woman who have pre-existing heart disease.

Third trimester(29 to 40weeks)
In some women, stretch marks develop on the abdomen,breast and thighs.A dark line may appear running from the umbilicus to to the pubic hair.colostrum can be expressed from the nipples.
miner problems are common.many women become hot and sweat easily as body temperature raise rises slightly.more rest may be needed at this stage,though many women find it difficult to find a comfortable position.
The baby's head engages(drops down low into the pelvis)around the 36th week in a first pregnancy,but not until a few weeks later in subsequent pregnancies.This "lightening" may relive pressure on the upper abdomen and on breathing,but increases pressure on the bladder and may result in more virginal discharge.

Amniocentesis

A diagnostic in which a small amount of amniotic fluid is is withdrawn from the amniotic sac(the membranous bag that surrounds the fetus in the uterus).

Why it is done
The amniotic fluid contains cells and chemicals from the fetus that can be analyzed to detect abnormalities,such as down's syndrome and other chromosomal abnormalities.Amniocentesis can also detect genetic disorders (such as hemophilia,cystic fibrosis,and Tay-sachs disease),or
development disorders (such as spina bifida).It is also used to assess fetal disorders,such as rhesus incompatibility,and to check the maturity of fetal lungs.

How it is done
Amniocentesis is usually performed between the 16th and 18th week of gestation.Ultrasound scanning is used to estimate the age and position of the fetus,the placental site,and the amount of amniotic fluid A needle is then inserted through the abdomen and uterine wall into the amniotic sac,avoiding the fetus and placenta.A syringe is attached to the needle and about 20 to 30 ml of fluid is removed for analysis. Anesthesia is not usually required,although occasionally a local anesthetic is used.In most cases, the woman can go home soon after the procedure but is advise to rest foe about 24 hrs.

Results
The amniotic fluid is analyzed bio chemically and fetal cells are cultured for chromosomal analysis.Culturing cells for Chromosomal analysis may take up to four weeks and results may there fore not be available until 20 weeks' gestation As well as identifying fetal disorders, chromosome analysis revels the sex of the fetus.A woman should therefore indicate whether or not she wishes to receive this information.Some laboratories do not report the sex of the fetus.

Complication
There is a slightly increased incidence of miscarriage oe early rapture of the membranes after amniocentesis;recent studies show a risk of about 0.5%. Amniocentesis is therefore usually recommended only for women over the age of 35 (who more likely to have child with Down's
syndrome),or when there are other compelling medical reasons,such as family history of chromosomal abnormalities.

Ultrasound Scan

A diagnostic technique in which very high frequency sound waves (inaudible to the human ear) are passes in to the body,and the reflected echoes are detected and analyzed to build a picture of the internal organs or of a fetus in the uterus.The procedure is painless and considered safe.

Also called sonography ,ultrasound scanning was originally a spin-off from naval sonar (used to detect submarines in World War II) and was first used medically in the 1950s.The original ultrasound scanners produced still images;most modern scanners produced moving pictures,which are easier to interpret.

How ultrasound scanners works and how they are operated

Ultrasound waves are emitted by a device called a transducer ,which is placed on the skin over the part of the body to be viewed.The transducer contains a cristal that converts an electric current into sound waves.The waves used have frequencies in the range of 1-15 million hertz.At these high frequencies ,the waves can be focus into a fine parallel beam,which pass through a "slice" of the body if the transducer crystal is made to oscillate back and forth.Some of the waves are reflected at tissue boundaries ,so a series of echoes is returned.The transducer also acts as a reciever,converting these echoes into electrical signals,which are processed and displayed diamentional image of the scaned boady slice By moving the transducer across the outer wall of the abdomen, views of the growing fetus are obtain from various angles,so it is possible to screen for abnormalities.


Ultrasound waves pass readily through soft tissues and fluids,making this procedure particularly useful for examining fluid-filled organs (such as the uterus in pregnancy ,and the gallbladder)and soft organs (such as liver).Ultrasound waves cannot ,however, pass through bone or gas.They
are thus of limited use for examining regions that are surrounded by bone(such as adult brain) or that contain gas (such as the lunger or intestines).



Uses for pregnancy

One of the most common uses of ultrasound is to view the uterus and fetus in pregnancy.
ultrasound scanning is often performed about 16 to 18 weeks in to the pregnancy,but may be performed at any stage.If the date of conception is known,the scan shows whether the fetus is of the expected size;conversely,fetal size can help establish the accurate date of conception and therefore predict the expected date delivery.The scan also reveals whether there is a multiple pregnancy .It is also possible to identify certain gross abnormalities ,such as anencephaly or spina bifida.Congenital Heart diseses can some times be detect,enabling the baby to be delivered in hospital that specializes in correcting such defects soon after birth.The scanne also shows the position of the placenta.If the

placenta in a position that could be obstruct normal childbirth(a condition known as a placenta previa),delivery by caesarean section may be necessary.
Scans earlier in pregnancy may be perfomed if the doctor suspects an ectopic regnancy(presence of an embryo outside the uterus),
hydatidiform mole (abnormal tumer in uterus),impending (miscarriage,or early death of the fetus.
Ultrasound is also vital for the procedure of amniocentesis (removal of amniocentic fluid via needle for analysis).A scans shows the position of the fetus and placenta before eather of these procedures and also helps in guiding the needle in to the uterus.
Later in pregnancy,the scan may be carried out if the growth of the fetus seems slow,if fetal movements cases or or are excessive, or if the mother experiences viginal bleeding.For high-risk or overdue pregnancies,a scane may be carried out before delevery to check on an fetal size,development and position in the uterus,the amount of amniotic fluid,and to recheck the position of the placenta.

How It Is Performed

If the scan is being performed on a woman who is in the early stages of pregnancy, she will be asked to drink several glasses of water about an hour before the scan. She also will be asked to refrain from urinating because a full urinary bladder allows for clearer visualization of the uterus and fetus by displacing nearby loops of intestine.


For all ultrasound scanning, the person lies on an examining table, clothing over the reagion to be scanned is removed and a special water-soluble gel is applied to the skin area to be examined. The gel may feel cool to the skin. The transducer is placed on the skin, positioned over the internal organ or structure that will be scanned, and gently pressed against the area that has been lubricated with gel. For certain examinations, a wandlike transducer may be inserted into the vagina or rectum. For example, in early pregnancy, insertion of the transducer into the vagina allows a closer view of the uterus and fetus. A rectal probe is helpful for assessing a man's prostate gland. Ultrasound scanning is generally considered painless and does not require special care after the procedure.

Antenatal Screening

Test carried out during pregnancy to check for abnormalities ,disorders or infection in the mother or her unborn baby.
there are some common antenatal screening during pregnancy but some tests are not necessary to do all other than any special cases.

Blood tests

• To check the woman's blood group and,sometimes to check for presence of hepatitis B virus which might be transmitted to the baby.
• To check foe anemia in the woman and with Rh-negative blood groups,to look for the presence of Rhesus antibodies.
• To screen for immunity to rubella which can cause defects in the baby,and for syphilis and other possible infections.
• In some cases, the amount of alpha-fetoprotein in the blood is determine whether baby has spina bifida.

Blood and Urine Tests

• To check for diabetes mellitus
• May be administered to assess placental function and well-being of the fetus.

Urine tests

• To check proteinuria,which could indicate a urinary tract infection or pre- eclamsia.

Cervical smear

• To test for an early cancer of the cievix(if a test has not been performed recently)

Blood pressure check

• To screen for hypertension ,which interferes with blood supply to the placenta and is a sign of pre- eclampsia

Chorionic villus sampling

• May be perfomed if there is a risk of certain genetic (inherited)disoders being passed on.

Ultrasound scanning

• Is carried out to date the pregnancy accurately and to detect any abnormalities present in the fetus.
• Extra scans may be recommended to assess fetal growth and development,the location of the placenta,and the amount of amniotic fluid.

Amniocentesis

• Carried out an older women and those who have children with spina bifida or Down's syndrome to detect possible abnormalities in the fetus.

Fetoscopy and fetal blood sampling

• In some cases these are carried out if there is doubt about the normality of the baby.

Electronic fetal monitoring

• To check n the fetal heart beat.

Preparation for Childbirth Classes

Childbirth preparation classes are given in hospitals ,health centres, community meeting places,or private homes.Such classes are aim to provide information on all aspects of pregnancy,labour and delivery,including advice on exercise, diet and sexual activity.The woman learns what happens during labour and different types of pain relief available during it;she may also learn breathing exercise to help her cope better with labour and delivery.

Attending Childbirth preparation classes are very beneficial for a number of other reasons too;such as pergnant mother will make new friends, who are also pregnant, this way you can focus on your baby and learn more through discussions, If pegnant woman is attending antenatal classes at the hospital, she might be taken on a tour around the labour ward, nurseries and postnatal areas. You will also be told where to go when you are in labour.Knowledge she will gain at antenatal classes is priceless, you will really need it and it will help you prepare for the unforseen.