Obstetric pregnancy calendar: what trimesters
Many women can not understand why their own count of pregnancy does not coincide with a period set by the obstetrician-gynecologist of female consultation.But this is not surprising, since the calculation of the pregnancy goes to different landmarks, so the result is different.
What is obstetric pregnancy calendar
Obstetric pregnancy calendar as a starting point (or pregnancy) takes the first day of the last menstrual period of women.Of course, in this day conception can not occur because the egg has just started to ripen.Ripen it in the middle of the menstrual cycle, after two weeks (usually it is, but in some women menstruation more or less).At this time ovulation occurs Ovulation - How to determine as accurately as possible? (release of an egg from the ovary) and its sperm fertilization (conception).Therefore, the true duration of pregnancy (also called the embryonic period) usually occurs after obstetric period of two weeks.
All obstetric pregnancy calendar is divided into weeks, months and trimesters.Week - is 7 days, 4 weeks or a month of 28 days, the entire pregnancy lasts 40 weeks or 10 obstetric months.For the convenience of monitoring the entire pregnancy pregnant woman is divided into three segments, or trimester: I trimester - the first 12 weeks, II trimester - 13-24 weeks, III trimester - 25-40 weeks.Each trimester has its own characteristics that distinguish it from the other trimesters.
I trimester (0-12 weeks)
This trimester is marked by hormonal changes a woman.In a woman's body produces a large number of the female sex hormone progesterone Progesterone - norm and pathology , which prepares the uterus for pregnancy and tries to keep this pregnancy by inhibiting muscle contractions of the uterus.Since smooth muscle is not only in the uterus, and in other internal organs, their physical activity is also inhibited.This is particularly reflected in the gastrointestinal tract: slow evacuation of food from the stomach can cause nausea and vomiting, and decreased motor activity of the intestine - constipation.The appearance of these unpleasant events also contributes to increased vagal tone - a long nerve that extends from the brain and also constrains the movement of muscles of the gastrointestinal tract.
situation is aggravated by the fact that a woman's body has not yet formed the placenta, which will protect it from unnecessary stress on the part of the metabolism of the fetus.All unpleasant symptoms I called early trimester of pregnancy toxemia.Usually, it is not terrible - all the phenomena of toxicity are after the placenta is formed.
pregnant woman is better on the first week to be registered - this could allow time to identify such complications as ectopic pregnancy.In addition, a woman must go through the necessary research, whose main task - to identify and treat all potential complications (infections, hormonal disorders, and so on).
II trimester (13-24 weeks)
II trimester of pregnancy is the calm and pleasant for the woman.She has already formed the placenta, and completely disappeared all signs of early toxicity, but are no shortness of breath and severity of subsequent months of pregnancy.Woman prettier, and is engaged in the affairs, it looks even better than before pregnancy.
this trimester also conducted a survey on hormones and ultrasound examination of the fetus, amniotic fluid, fetal membranes, placenta and the uterine wall.During this period, pregnancy examination reveals all the possible malformations of the fetus, as well as the possible chromosomal (eg, Down syndrome), and hereditary diseases.
Complications of this trimester: miscarriage Miscarriage - why you lose the most precious thing? (late miscarriage), bleeding (usually a reason - placenta previa), iron deficiency anemia, lack of oxygen (hypoxia) of the fetus.The fruit is very responsive to the lack of oxygen: it changes the nature of the movements, the frequency and heart rate.
All this is revealed in the survey and, if necessary, treatment of women appointed and a special breathing exercises.It is important that in the second trimester the fetus is well supplied with oxygen, because in this period is very rapidly developing brain.
this trimester it's best to be trained in the school of mothers, it is best to do it with her husband, because it is possible that he will help his wife in the first stage of labor.And some men even present at birth.
III trimester (25-40 weeks)
Start III trimester quiet.But as the child grows, a big belly starts to prop up the bodies of the thoracic and abdominal cavities.There are problems such as acid reflux (stomach acid into the esophagus), constipation, shortness of breath (compressed lungs and heart), varicose veins, hemorrhoids.Almost every woman these effects to a greater or lesser extent are present.Zoom can be only through proper nutrition Proper nutrition - basic precepts of healthy food and high motor activity, which need to be alternated with frequent rest.
But the term has come to give birth.The most important thing at this stage - to calm down, gather your strength and go to the hospital.