How to Calculate a Birth Date Delivery


The first thing a woman wants to know once she has been told she is pregnant is when her little bundle of joy will arrive. The average amount of time for gestation is 280 days or 40 weeks from the very first day of a woman’s last menstrual period. Provided you have tracked the dates properly, calculating the day the baby will be born is quite simple. For example, if the last date of your last menstrual period was October 23, your due date will be August first. The way you would come to this date would be to add nine months and seven days to the date. This is one reason keeping track of your menstrual period is extremely important.

Typical Time Frame for Pregnancy

While not all babies are born on their exact due date, in fact most of them aren’t, this method of calculation gives you a very good idea of the timeline you are looking at. Most babies, at least 80% of them are born within about ten days of the calculated due date. When a baby is born sometime during the 38th and 42nd week, this is known as a “full term” pregnancy. While the majority of mothers do deliver their babies within the expected time frame, there are still about 20% of births which occur outside of the normal time constraints. Approximately 8 to 10% of babies are born sometime during the 20th and 36th week. In addition, about 8% of babies are born late, after the 42nd week.

Preterm or Premature Births

Unfortunately, there are many factors which can contribute to a baby being born too soon. In some cases signs of early labor can be treated successfully and labor delayed until a more appropriate time. In other cases there is nothing that can be done and early birth is eminent. Premature births are quite common in mothers who are pregnant with multiples. Another factor which may contribute to a preterm labor is a misshaped uterus that does not allow the baby enough room to fully grow. There is also quite a bit of data to suggest that smoking can lead to premature labor. High blood pressure, renal disease, diabetes and even high fevers and infections can also cause a woman to go into labor early. Then of course there are more rare incidences such as placenta previa and placental abruption which can play a role in early labor.

The biggest concern with preterm babies is the fact that in many cases their lungs are not fully developed. Even in cases where every other organ has developed adequately, the lungs can pose a problem. While there are a lot of advances in the treatment of babies born prematurely, the leading cause of still born babies and babies who die just after birth is still premature birth.

Post Term Birth

There is no known cause for a baby to be born too late. However there is data to suggest that a woman who has given birth to one post term baby has a much greater chance of having a reoccurrence with subsequent pregnancies. Fortunately, the main cause of “post term” labor is actually a miscalculation on the mother’s part. If she has miscalculated the last day of her last menstrual period, the due date can be thrown off.

While Post term pregnancy poses very little threat to the mother, a placenta will dramatically lose its ability to transmit nutrients and oxygen once it has aged beyond the 42nd week. Sadly, in many cases this decline in placental ability can lead to fetal distress and ultimately death. There is a distinct appearance to babies who do survive post term birth. Most of the time they will have an abundance of hair, long finger nails, wrinkled, cracked and peeling skin, as well as a very small amount of fat below the skin. In addition, many post term babies eliminate their first bowel movement, meconium into the amniotic sac prior to delivery. In these cases, if the baby should happen to inhale any of the meconium into his/her lungs during delivery, severe complications such as pneumonia can occur.

Prenatal Care

While knowing the expected due date for your baby is extremely important, it is even more vital to be sure you never slack on prenatal care. Not only can proper prenatal care prevent a number of issues from arising as a result of negligence, but it can also detect any sort of distress you or the baby may be having. The first prenatal appointment is usually scheduled at 4 weeks pregnant. After that you will see the doctor about once a month until the 28th week. After week 28 your doctor will want you to come in bi-weekly until you reach 36 weeks, at which time your appointments will occur once a week until the time of birth.

Not only will adequate prenatal care help prevent problems and detect any illnesses in mother or baby, but it is a great avenue for moms to receive answers to the many questions they are bound to have during pregnancy. In addition, birthing classes and first time mom classes are excellent resources for new parents. The birth of a baby is a very special time in your life and taking all precautions to ensure that it goes smoothly will save you a lot of problems in the long run. Proper care and organization are vital for a healthy and happy pregnancy.

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Margrit Bradley

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