There is only one rule: any bleeding, however minor, should alert you to immediately consult your doctor; this is even more important if it recurs or if there is also the slightest contraction of the uterus, or passing of clots.
The term of pregnancy is set at 41 weeks, plus 6 days counting from the first day of the Last Menstrual Period (LMP). The strict mean duration of pregnancy is 282.5 days. If pregnancy continues after the expected date, the term postdatism or postmaturity is used. In postdatism there is an increase in distress and sudden 'in utero" death. Indeed, until term, the placenta usually provides the foetus with food and oxygen which it requires. As the pregnancy continues, the placenta becomes less efficient. The amount of food and oxygen supplied to the foetus becomes inadequate, and thus there is a risk of foetal distress.
Uterine contractions should alert you that there is a problem only if they are painful. During the last two months of pregnancy, if painful contractions occur together with vaginal bleeding, it is a sign which alerts your doctor that the placenta may be implanted in the lower uterine segment. Do not become alarmed, but instead consult your physician. In the vast majority of cases, the pregnancy can continue its normal course with rest, certain medications, including hormones, if necessary.
Up until the fifth month, the foetus is free to move about inside the uterus and can kick against the mother's abdomen. Then there is increasingly less room and the fetus has just enough space to turn and move. He has alternating phases of sleep and activity. What is important is that you feel the foetal movements every day. If such movements becomes less frequent and weaker, you should immediately consult your doctor. Doppler ultrasound will reassure you by allowing you to hear the foetal heart tones.
This condition is common in early pregnancy, the placenta is implanted onto the lower uterine segment; but, generally, after a few months, it reascends and occupies the upper part of the uterus. This is why low insertion of the placenta can only be suspected on ultrasonography after the first trimester. Until then, it is not in its definitive position inside the uterus.
Contractions of the uterus, even weak, can detach the lower border of the placenta and cause minor bleeding.
This is not serious but requires rest, medical therapy and strict monitoring with ultrasonography. In over 90% of cases, a low-implanted placenta ascends as the uterus grows into the uterine cavity and does not cause any further problems. If unfortunately the placenta is implanted in the lower uterine segment near the cervix, and even more so if it "covers over" the internal os, this requires absolute bed rest and prolonged hospitalisation of the mother in late pregnancy, because of possible bleeding. A cesarean section may sometimes be necessary.
When foetal distress occurs, the foetus lacks oxygen and nutritional elements necessaary for harmonious development. Such distress is manifest by a change in foetal heart rate. Foetal distress can develop in late pregnancy and then become "chronic." It is caused especially by hypertension in the mother or by a retroplacental hematoma; each case requires individual management.
When pregnancy continues past 42 weeks (postmaturity), the physician must monitor the patient carefully: at such a time, the placenta begins to function less efficiently; supplies of oxygen and food become inadequate, and can results in foetal distress. The most common cause is compression of the umbilical cord to a variable extent during delivery. Before the baby is born, he is free to rotate around the umbilical cord which may go around his neck or his shoulder in suspender-like fashion; during contractions of the uterus, there is decreased oxygen to the foetus and the heart rate slows, all the more so if the cord is tightly wrapped around his neck.
It is obvious that slowing of the foetal heart rate of short duration during a contraction of the uterus and its rapid return to a normal rate correspond to a temporary restriction of oxygen only; on the contrary, a prolonged decrease in heart rate after a uterine contraction leads to suspect foetal distress. Thus, the physician bases his judgment on the monitor tracing and any flattening in the curve to accelerate delivery or, if necessary, to extract the baby by caesarean section.
Currently, in some cases physicians can prescribe medications which cross the placenta and regularise the foetal heart rate; such treatment will be continued after the baby is born. Some types of anemia can also be treated in utero with transfusions through the umbilical cord. These drugs thus help prevent foetal distress.