Tough Time Deciding on a Name for Your Baby ?

The conversation went something like this:

Hey honey, when we get pregnant, how about if we name our baby Jack, if it’s a boy?” The husband responded, that no, he indeed did NOT like that name. As time went by, they acquired a cat. They were having a hard time finding a name for the male feline. Finally the husband just said, “You like the name Jack so well, let’s give that name to the cat. Because I am NOT having a son named Jack.”

So the couple went happily on their way, enjoying the newlywed life and their new cat, Jack.

After a bit of time passed, the happy couple learned they were expecting a bundle of joy to be born later that year. They began the overwhelming task of deciding on names. It’d be easy if the baby was a girl. They agreed upon a girl’s name long before they were ever married.

They poured over baby naming books; they shared ideas; they made lists; they tried coming up with a boy’s name using this method; then they tried that method. Still nothing. They could not agree on a boy’s name.

Thanks to modern technology the couple learned that they were having a baby girl. Their naming problem was solved! They proceeded with the remainder of the pregnancy preparing for the baby girl who already had a name. They even called the baby by her name as the husband read to the pregnant belly.

But then yet another ultrasound revealed that the little girl they had come to know and love was actually a little boy!

The baby was scheduled to make HIS delivery into the world in relatively short time. The parents frantically went back to the tireless task of finding a boy’s name they could both agree upon.

One night the husband announced that he liked the name Jack for his son! (This is a true story ladies … can you even imagine how you’d feel if your husband announced this grand revelation?)

To the wife’s dismay she reminded her husband that he was the one who did not like that name; in fact went as far as to declare he would NOT have a son named Jack. She then jogged his memory that they had a cat named Jack. Jack the cat even responded to his name.

You may have guessed the rest of the story. The cat now has a new name. It is rather original. The feline is now known as Kitty Cat (K.C. for short). And they have a beautiful son named Jack.

What’s the moral of the story? If you are having a hard time coming up with a perfect name, you just might try the name you’ve given to the family pet!



Ref : http://www.babychildcare.com/index.asp

The O+12 Method to Conceive a Baby Girl

O+12 (pronounced "oh plus twelve") is a method for conceiving a girl. The method advises intercourse about 12 hours after ovulation to conceive a girl. Thus the name O (for ovulation) plus 12 hours. O+12 is contrary to the Shettles method, which predicts a boy will be conceived on the day ovulation. (Note to boy-seekers: O+12 is a method for attempting to conceive a girl only.)
O+12 Background
The O+12 method wasn't developed by a doctor, or published in a book. It was proposed by an Australian mother, a Shettles devotee who had six sons before stumbling on the idea that a girl might be conceived by timing intercourse just after ovulation, contrary to Shettles' advice. After giving birth at last to a daughter, she shared her method with other mothers, many of whom were successful in conceiving a daughter as well. Then the method reached the Internet, and here we are. Click here to read Kynzi's story.
O+12 Theory
The O+12 theory was developed by examining the "New Zealand Study" published in 1984. The study was carried out to test the Shettles theory, by carefully monitoring participants to determine the time of ovulation.

(Just think... the baby girls born in that study are now old enough to become mothers themselves, and perhaps are today wondering how to choose the sex of their baby.)

The researchers concluded that the results "clearly refute" the Shettles theory, because most conceptions that occurred 3 to 5 days before ovulation were boys, not girls, as Shettles claimed. Kynzi noticed that the only day on which more girls than boys were conceived was the day following ovulation.

In addition to the New Zealand Study, some information was evidently uncovered indicating that the ratio of female-to-male sperm was greater if a man abstained from ejaculation for a period of time.
The O+12 Key: Pinpointing Ovulation
Before getting into the detailed instructions for O+12, it's enough to say that a successful O+12 attempt depends on being able to pinpoint ovulation. Most of us have spent our entire lives completely unaware of the invisible drama of ovulation that occurs inside our body each cycle. Be prepared to spend some time learning about how your body works (you will be fascinated and enlightened!) and learning how to detect your body's subtle signals that ovulation is imm"inent. Your guide is Taking Charge of Your Fertility, and you mig"ht also want the OvuSoft Fertility Software to go along with it.
O+12 Instructions

1. The father must not ejaculate for at least 7 days before intercourse (and preferably longer).

That didn't say "no sex", it said "no ejaculation", so you better keep an eye on him in the shower. Try to get him to abstain from the first day of your cycle.

The reason for this is that since female sperm supposedly live longer, an "old" batch of sperm should have more female than male sperm (about 2% more, according to some data).
2. Have intercourse once only, 8 to 20 hours after ovulation.

Start counting the 8-20 hours when...
* Any sharp O pain has subsided.
* Your CM begins to change from EWCM to creamy or sticky.
* Your cervix begins to become less soft and high.
You should wait to have intercourse until you have seen one high BBT (morning or evening) to confirm that ovulation has truly past. (See the tips below for more information.)
3. Do NOT have intercourse again until you are sure you are no longer fertile.

Use a condom or wait until you are sure you are no longer fertile before having intercourse again, because that "fresh" batch of sperm will be more likely to have more male sperm.
* You are past your fertile stage when you have had THREE high temperatures on your BBT chart.
4. Optional guidelines.

Along with O+12, many also try:
* The girl diet
* Supplements (calcium and magnesium, cranberry)
* Douching before intercourse with a lemon douche (mix the fresh-squeezed juice of 1/2 lemon with an equal part of water, and insert with the empty bottle from a regular store-bought douche).

O+12 Tips
Pinpointing ovulation down to the hour is the key to O+12, and it's not easy. Most ovulation detection methods are just designed to determine the day of ovulation, which is generally good enough to achieve (or avoid) pregnancy. For O+12, we have to be ovulation experts.

Tip #1: Practice, practice, practice!
Track your ovulation indicators for several practice cycles. Many times, the time of ovulation can only be determined in hindsight. Practice cycles will give you confidence that you know when ovulation is occurring, and will also give you something to compare to when you're ready to make your attempt.
Tip #2: Use as many ovulation indicators as you can!
No matter how regular you are, or how many cycles you practice, each cycle is different. Gather as many clues as you can to determine the real moment of ovulation. Ovulation indicators include basal body temperature (BBT), cervical mucus (CM), cervical position (CP), saliva ferning, and ovulation prediction kit (OPK) testing. The great book Taking Charge of Your Fertility explains in detail how to use these methods to determine ovulation.
Tip #3: Watch your CM and your CP.
Your cervical mucus will usually change within hours of ovulation, changing from EWCM to creamy or sticky. Start counting the hours when your CM has started to change, and your cervix is not very high and soft.
Tip #4: Take your basal body temperature effectively.
Basal body temperature is a reliable method for detecting that ovulation is truly past, so make sure to take your temp carefully, and wait to have intercourse until you have seen your BBT shift up.

However, taking your BBT once per day can only tell you that ovulation has occurred within the last 24 hours -- and by then you may be too far past ovulation to actually conceive, because the egg only lives about 24 hours. You may want to try also taking a second BBT temp in the evening. It will not be as accurate as your morning "at rest" temp, but if you take it at the same time every night after the same routine you will be able to see a pattern. Taking your BBT in the evening in addition to the morning should help you detect ovulation within the last 12 hours.

* Note that your body temperature will be different in the evening -- you can't compare your morning and evening BBT's to each other. You can only compare your morning temps with previous morning temps, and evening temps with previous evening temps.

Tip #5: Take note of O pain.
O pain (ovulation pain, or mittelschmerz) can be pinpoint the exact time of ovulation -- but it can also fool you, because a little random twinge you would have ignored at any other time can mislead you if you're looking for ovulation to occur. Not everyone has O pain, and if you do, it may not be in every cycle. O pain tips:

* Chart any O pain you experience in your practice cycles, and note how it correlates with your other symptoms. You may notice that O pain occurs at about the same time of day that your previous period began.
* Recognize the different kind of O pains: A dull achiness before ovulation, a sharp pain at ovulation, and crampiness after ovulation.
* The pain should come from toward your side (not from the center) and may be only on one side.

Tip #6: Use OPKs as advance warning only.
A positive ovulation prediction kit is a sure sign that ovulation is going to occur, but it does not give you an accurate prediction of when; it might be anywhere from 12 to 36 hours. When you get your first truly positive OPK, begin watching your other ovulation indicators (BBT, CM, CP, O pains) to determine exactly when ovulation is occurring.



Ref : http://www.in-gender.com/Gender%2DSelection/Oplus12/

Caring For Twins

Twins can really be fun to welcome into the family. After all, two babies mean double the fun and double the love! And who can resist two cute, cuddly little babies? If you have just had twins though, you are probably finding that caring for them is actually quite challenging. New mothers of twins often find themselves overly-fatigued, exasperated, and even overwhelmed at times. If you are pregnant with twins, it is a good idea to anticipate the challenges that raising two babies will bring but is also important not to panic! Here are some great parenting tips to help you care for those multiples while retaining (most of) your sanity!

When the Twins Arrive: Your Emotions
When your twins first arrive you will undoubtedly be overcome with joy and emotion. Giving birth to a baby is a big step in life, and having two is even a more wonderful. However, as the days and weeks pass, and the work begins to pile up, you may begin to feel a variety of emotions. Mothers of twins often feel:

* overwhelmed
* fatigued
* sad or depressed
* frustrated
* angry
* lonely

It is important for you to acknowledge these feelings as they arise. Try talking to your partner about how you are feeling, or write down your emotions in a journal when you have a spare minute. Remember that parenting twins is a big deal, and you can expect to go on a bit of an emotional rollercoaster. In time, your emotions will begin to settle down.

Asking for Help
Asking for help can often be a saving grace when it comes to parenting twins. Don’t be afraid to look to others for a helping hand, whether it be to watch your babies for a while or to help out with the housework. Family members, friends, and neighborhood moms are often happy to lend a hand. Or, you may think about hiring someone to come in occasionally to get extra dishes, laundry, or chores done.

Breastfeeding Twins
Many moms of twins and multiples wonder whether or not they will still be able to breastfeed. The benefits of breastfeeding are numerous, and, if possible, it is a good idea to breastfeed your twins. Many moms find that breastfeeding twins isn’t all that difficult, because increased demand actually creates an increased supply of milk. Here are some breastfeeding tips to help keep your twins happy:

* Breastfeed your babies at the same time. This will help to get them on a feeding schedule and will save you precious time during your day.
* Alternate feeding your babies from both of your breasts. This will give your babies visual exercise and encourage them to drink more milk.
* Get a twin nursing pillow. This pillow aids in supporting both babies while you are feeding them, preventing muscle aches and pain.
* Invest in an electronic or manual breast pump. These pumps help you to collect milk from both of your breasts, allowing you to dump old milk or collect milk for future feedings.
* Talk to a lactation consultant or sign up for a breastfeeding class to make the going a little easier.

Establishing Sleep Patterns
In order to manage all of your responsibilities, it will help if you can establish a good sleep routine for your twins or triplets. Try to get your babies to sleep at the same time, if at all possible. This will allow you time to rest or relax. To establish a sleep routine, try out these tips:

* Engage in soothing behaviors before bedtime arrives. Give your twins a bath, read them bedtime stories, or just cuddle with them. Eventually, these activities will act as signals to your little ones that it is time to take a nap.
* Encourage your babies to drift off in your arms before you put them down. When babies are drowsy, they are more likely to fall asleep.
* Let your little ones sleep together. Twins will often hug or touch one another in bed, and this helps them to fall asleep. It is usually okay for twins to nap together until they are three months old.
* Prevent any sleep time disturbances by keeping their room dark and quiet. Avoid handling your babies after they have gone to sleep. If you need to feed them, put them back into bed immediately afterwards.

Take Care of Yourself
In order to provide the best care for your twins, it is important that you take care of yourself. Be sure to maintain a healthy and balanced diet as you did during pregnancy. Eat plenty of snacks and be sure to keep up your calcium intake. Try to get one to two additional servings of calcium each day, or take a calcium supplement. Remember, you will need 400 to 500 extra calories each day, for each child that you are nursing, so enjoy your food! Sleep whenever possible, and try to get out of the house at least once every day. Visit with other moms or join a twin playgroup so that you can talk with other adults!

Caring for Special Needs Twins
Unfortunately, many twins are born before their due dates, and this can make caring for your little ones even harder. Premature twins often require special care and nutrition. Here are some tips on caring for your special needs twins:

* Begin pumping breast milk right away. Your twins may not be strong enough to breastfeed, but your breast milk is full of valuable nutrients that will encourage growth and development. It will also help them to fight off infection.
* Ask about co-sleeping if your babies are in neonatal care. It has been shown that twins who are allowed to sleep together have more regular breathing and sleeping patterns.
* When your babies come home, be sure to maintain regular health care appointments. Preterm babies need regular health checkups to keep an eye on their nutrition, development, and growth.
* Evaluate your babies’ milestones based on an adjusted age. Preterm babies often develop more slowly than full-term babies. Subtract the number of weeks or months that your babies missed in your uterus when calculating when they should begin sitting up, walking, or talking.



Ref : http://www.pregnancy-info.net/caring_for_twins.html

Caring for A Premature Baby

Premature babies need extra special care from their parents. Premature babies face distinct physical and emotional challenges, such as impaired hearing and vision, jaundice and anemia. While preemies often need treatment from a neonatal intensive care unit (NICU), parents too play a crucial role in promoting healthy development in their baby. From feeding and sleep, to clothes and changing, preemies require unique attention to ensure they will grow and develop properly, both physically and emotionally.

Preemie Clothing: More than Just Fabric
Because of their small size and lack of body fat, premature babies need special clothes that will fit them and help them stay warm. Keeping baby warm and comfortable is important in keeping him happy and relaxed. Preemie clothes must also have easy openings that will allow for frequent diaper changes and for easy hook-up to any hospital equipment that your baby requires.

Feeding: Time to Bond with Baby
Feeding is a unique time between a premature baby and her mother. Preemies often require feeding through IV or gavage feeding (in which they are fed milk through a tube).

Therefore, when new moms can breastfeed directly, skin-to-skin contact is encouraged during feeding in order to increase the ability to bond. Breast milk can also be administered via medical equipment, as in gavage feeding.

New mothers are also encouraged to keep up their milk supply, pumping breast milk every two to two and a half hours. Feeding should be a calm, relaxing ritual for both infants and their mothers. Preemies require feedings from eight to ten times a day, more than non-premature babies.

When solid foods are introduced, usually after four to six months, meals should be small and frequent to ensure that premature infants get enough nutrition to allow them to grow.

Changing: Diapers for Preemies
Preemies need changing six to eight times a day. This amount of diapers signals that your baby is getting enough nutrition. Diapers are available especially for premature infants so that they fit right and can be opened without undressing the baby, which is important for hospital-related care procedures.

Sleep: Preemies’ Special Needs
Babies born prematurely have different sleeping patterns and needs too. They sleep more hours a day than other babies do because of their special developmental needs. However, they tend to sleep in smaller increments, sometimes making it difficult to ensure that they get enough quality sleep. To make sure they do, limit exposure to overly stimulating environments and outsiders.

Preemies are also at a greater risk of dying from SIDS. Place preemies to sleep on their backs, even if it’s only for a nap. Make sure their mattress is firm, and that no toys are in their crib. Also be sure that nothing is covering the baby’s head or face.

Extra Tips for Preemie Parents: Promoting Growth and Development
Having a premature baby is a physical and emotional challenge. It can lead to feelings of anxiety, anger, guilt, sorrow and even regret. In order to reduce the negative, long-term effects of such feelings, learn as much as you can about your baby’s condition. Jot down any questions or concerns and discuss them as soon as possible with your doctor.

Another important tip is to share any observations of changes in your infant’s condition with your doctor as soon as possible. This will ensure your baby gets the care he needs right away.

Taking care of yourself is also a really good way to promote healthy development in a premature baby. Taking breaks from the care process, establishing support networks and keeping a journal are all great outlets to voice your concerns and ease any negative feelings you may be experiencing. This will help you stay calm and healthy and happy, and therefore your baby too.



Ref : http://www.pregnancy-info.net/premature_care.html

Pregnant Again?

Congratulations! You're pregnant again and your family is growing. You are most likely feeling calmer since you know what to expect this time around. You may even want to start a pregnancy journal so that you can be sure to remember this special time. Let's face it, by now you are a well-seasoned mom and your baby will soon become a big brother or sister.

However, you probably have some questions about how this pregnancy will be different from your first. Will your this pregnancy be harder than the before? Probably not. Because your cervix has softened, your delivery time may be quicker and most likely easier. Second pregnancy symptoms will also start to show sooner.

Yet, the second pregnancy may be harder if you had the baby blues with your first pregnancy. This indicates that you may have a more severe case with your second child. Also, if you had Rh disease your first time around, it could pose more of a problem this time. Again, most women feel more comfortable, as they've experienced this process once before.

Second Pregnancy Emotions

Second pregnancy issues wouldn't be complete without a look at the emotional and sociological changes that occur.

Responses to Your Pregnancy
If you have a second pregnancy soon following your first, you may notice some subtle, disapproving signals from friends and family. The same will be encountered if this pregnancy follows an already full nest. Don't let these sorts of reproaches affect your pregnancy.

Making Room
You will once again be changing the balance of your family dynamics. There will be less time to spend with either your husband or your older child once you're caring for the newborn. The upside is that you've conquered these issues once before and know what to expect.

For your older child, be sure to prepare them for the upcoming birth and consider allowing your child to attend the baby’s birth.

Possible Second Pregnancy Complications

Rh Disease in Second Pregnancies
Everyone is born with either Rh positive or Rh negative type blood. About 15% of Caucasians and 5% of African Americans have Rh negative blood. Because the Rh antigens found on the red blood cells are a dominant genetic trait, whenever an Rh negative woman has a child with an Rh negative man, there will be a great probability of the baby being Rh positive. If the fetus' blood should happen to leak into the mother's blood stream, her blood will develop antibodies that will attack her baby's red blood cells.

Rh disease can cause low or high-risk anemia or inter-uterine death. Second pregnancies run a greater risk of Rh disease as the previous baby's blood probably mingled with the mother's blood stream during delivery.

Prevention. Regardless of your baby's blood type, your doctor may inject you with RhoGam at 28 weeks. This will destroy any of your baby's blood cells that enter your own blood stream to prevent your body from creating antibodies.

Treatment. Rh titers, or the amount of antibody you have, will have to be measured throughout your pregnancy. If levels become critical, amniocentesis will be conducted in order to transfuse your baby's blood supply to Rh negative. The transfusion takes place through the umbilical cord. These procedures are a bit risky and therefore doctors sometimes prefer to induce early labor and then administer the blood transfusion.

Hyperemesis and Your Second Pregnancy
Women who experienced Hyperemesis Gravidarum (HG), a severe form of morning sickness marked by persistent vomiting and weight loss, in their first pregnancy may have to deal with it again in a second pregnancy. However, you can help lessen the symptoms by taking precautions before you get pregnant. Eat a very nutritious and healthy diet and take antioxidants and prenatal vitamins in the months prior to conceiving. If you do experience HG symptoms again, be sure to consult your doctor.

Preeclampsia During Second Pregnancy
Low birth weight in your first pregnancy can point to whether you will acquire preeclampsia in your subsequent pregnancies. A low birth rate notifies that you are at a greater risk in your second pregnancy. Women whose babies were born under the third percentile of birth weight were three times more likely to develop preeclampsia in later pregnancies.



Ref : http://www.pregnancy-info.net/pregnant_again.html

Pregnancy Symptoms

Symptoms of pregnancy may vary from woman to woman and even pregnancy to pregnancy. While not all will occur with every pregnancy and some symptoms are in fact rare, following is a list of some of the potential symptoms of pregnancy.

* Implantation, the female body begins to adjust to prenatal stage. There may be some twinge associated with implantation. (Generally 7-10 days after fertilization.)
* Distended abdomen, this symptom rapidly increases during the second trimester.
* Delayed or difference in menstruation.
* Minor vaginal bleeding (spotting).
* Swollen or tender breast, minor lactation in third trimester.
* Fatigue, also may experience sleeplessness.
* Nausea, sometimes accompanied by vomiting, esp. the first trimester, most likely to start at around 7 weeks. (morning sickness).
* Lower backaches.
* Sensitivity in teeth, higher risk for gum disease.
* Headaches, some women reported migraine-like types.
* Long frequent hiccuping spells.[1]
* Enlarged feet and hands, or expanded buttocks.
* Frequent urination; occasionally urinary incontinence.
* Constipation, but a few encounter random defecation.
* Food cravings, or increased appetite.
* Fear of increasingly imposing burden.
* Heartburn or upset stomach, and sometimes vomiting caused by the nausea (some in the third trimester, due to fetal position "presses" the stomach).
* Stomach/intestinal gas, may be frequently flatulent or belch.
* Difficulty in walking and balance.
* Difficulty with contact or vision prescriptions.
* Hemmorrhoids and rectal irritaton.
* Changes in sense of smell.
* Exhaustion or increased breathing, some reported to have "deeper" voices.
* Skin gets blush, but can "soften" or moisten, and even can dry faster.
* A few reported hair loss, others have more body or "facial" hair.

Symptoms of pregnancy do not allow for a pregnancy diagnosis because each of these symptoms has the potential to be explained by other reasons (e.g. missing a period because of stress, hormone level change, etc).

Pregnancy does have a minor, but noticed psychological effect by hormonal changes and chemical reactions in some women, known as "mood swings" that are controlled.

Pregnant woman may experience periods of enhanced content, excitement or fickleness, and melancholy, anxiety or angst, but it often depends on how the woman views herself and attitudes on her condition in various ways.



Ref : http://en.wikipedia.org/wiki/Pregnancy

Start of Pregnancy and Predicting Date of Birth

Before pregnancy begins, a female oocyte (egg) must join, by spermatozoon in a process referred to in medicine as "fertilization", or commonly known as "conception" (though the definition of the English word "conception" is somewhat controversial). Fertilization occurs usually through the act of sexual intercourse, in which a man ejaculates inside a woman, thus releasing his sperm; however, the advent of artificial insemination has made it possible for women to become pregnant if pre-existing medical conditions from either the woman or the man make fertilization through sexual intercourse difficult, or if a woman chooses to become pregnant without a male partner, for any number of reasons. Though pregnancy begins at implantation, it is often convenient to date from the first day of a woman's Last Menstrual Period (LMP). This is used to calculate the Expected Date of Delivery (EDD).

Traditionally a human pregnancy is considered to last approximately 40 weeks (280 days) from the LMP, or 38 weeks (266 days) from the date of fertilization. The 38 weeks of gestation is 10 lunar months, i.e. 27.3 days/lunar-month x 10 = 273 days. In the more familiar Gregorian calendar, the 40 weeks dating from the LMP is equivalent to a little more than nine months and six days, and this forms the basis of Naegele's rule of approximating the EDD. 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 postmature.

Though these are the averages, the actual length of pregnancy depends on various factors. For example, the first pregnancy tends to last longer than subsequent pregnancies. Fewer than 10% of births occur on the due date; 50% of births are within a week of the due date, and almost 90% within two weeks. The due date is typically calculated as 40 weeks from the last menstrual period.

An accurate date of fertilization is important, because it is used in calculating the results of various prenatal tests (for example, in the triple test). A decision may be made to induce labour if a fetus is perceived to be overdue. Due dates are only a rough estimate, and the process of accurately dating a pregnancy is complicated by the fact that not all women have 28 day menstrual cycles, or ovulate on the 14th day following their last menstrual period. Approximately 3.6% of all women deliver on the due date predicted by LMP, and 4.7% give birth on the day predicted by sonograph.[citation needed]

The beginning of pregnancy may be detected in a number of ways, including various pregnancy tests which detect hormones generated by the newly-formed placenta. Clinical blood and urine tests can detect pregnancy soon after implantation, which is as early as 6-8 days after fertilization. Home pregnancy tests are personal urine tests, which normally cannot detect a pregnancy until at least 12-15 days after fertilization. Both clinical and home tests can only detect the state of pregnancy, and cannot detect its age.

In the post-implantation phase, the blastocyst secretes a hormone named human chorionic gonadotropin which in turn, stimulates the corpus luteum in the woman's ovary to continue producing progesterone. This acts to maintain the lining of the uterus so that the embryo will continue to be nourished. The glands in the lining of the uterus will swell in response to the blastocyst, and capillaries will be stimulated to grow in that region. This allows the blastocyst to receive vital nutrients from the woman. Pregnancy tests detect the presence of human chorionic gonadotropin. An early sonograph can determine the age of the pregnancy fairly accurately. In practice, doctors typically express the age of a pregnancy (i.e. an "age" for an embryo) in terms of "menstrual date" based on the first day of a woman's last menstrual period, as the woman reports it. Unless a woman's recent sexual activity has been limited, the exact date of fertilization is unknown. Absent symptoms such as morning sickness, often the only visible sign of a pregnancy is an interruption of her normal monthly menstruation cycle, (i.e. a "late period"). Hence, the "menstrual date" is simply a common educated estimate for the age of a fetus, which is an average of two weeks later than the first day of the woman's last menstrual period. The term "conception date" may sometimes be used when that date is more certain, though even medical professionals can be imprecise with their use of the two distinct terms. The due date can be calculated by using Naegele's rule.



Ref : http://en.wikipedia.org/wiki/Pregnancy