Contents
How is fundal height measured?
We use a meter of seamstress to measure the distance between the pubic symphysis (pubic bone) and the fundus, assessed by manual palpation. The tape measure is stretched vertically and the pregnant woman, whose bladder must be emptied, is stretched out so that the position of the uterus is always the same.
Pregnancy: when is fundal height measured?
This examination is performed from the 4th month of pregnancy (it is possible to start before but it is not very reliable) and until the end. The measurement is carried out once a month, or even more in the event of an anomaly. It is preferable that the same person is doing the exam. The way of measuring is thus identical each time and the measurement of the uterine height is even more precise.
Uterine measurement: what values are taken into account?
From the 4th month of pregnancy, the uterus should measure about 16 cm and then grow 4 cm per month until the 7th month. From 32 weeks of amenorrhea (beyond the 7th month), it evolves by 0,5 cm per week until term. We therefore compare the results obtained on pregnant women to the average uterine height:
- At 4 months: the average is 16 cm.
- At 5 months: the average is 20 cm.
- At 6 months: the average is 24 cm.
- At 7 months: the average is 28 cm.
- At 8 months: the average is 30 cm.
- At 9 months and until term: the average is 32-34 cm.
Fundal height: is the measurement accurate?
Theoretically yes, but it depends a lot on the position of the baby – if it is in a transverse position for example, it will decrease the height – and the abdominal volume of the mother-to-be. In other words, the stronger the latter, the more imprecise the measurement. In case of doubt about the growth of the baby, the mother-to-be will be subject to increased surveillance.
Pregnancy: what to do in case of weak uterine measurement?
What if the uterine measurement does not increase? The genetic character is important. The doctor or midwife will therefore first look at the medical file and more precisely the height and weight of the parents, but also, if applicable, those of the children already born. If it does not reveal any genetic predisposition, examinations, and in particular an ultrasound which will take the precise measurement of the baby (head, abdomen, feet, etc.), will be carried out. If the child’s growth retardation appears, further tests will be prescribed to determine the causes. It is in these cases that we find maternal hypertension or toxaemia or pre-eclampsia (delay generally detected during the 3rd trimester of pregnancy). But it can also be linked to a karyotype abnormality (the delay often appears in the 2nd trimester). There is in this hypothesis a risk of trisomy (trisomy 13 or 18). Depending on the anomaly and the term of the pregnancy, different options may be considered: rest for the mother-to-be, hospitalization, initiation of childbirth, etc.
Uterine height: what if uterine measurement is too high?
As in the case of a weak uterine measurement, the genetic factor will be analyzed. We will also be looking to see if the mother-to-be does not suffer from gestational diabetes. It can also be due to hydramnios (excessive accumulation of amniotic fluid), itself caused by a malformation of the fetus, especially of the digestive tract, or by neurological problems. An ultrasound will confirm the diagnosis. The growth of the baby will of course be monitored very regularly. The term, the extent of the excess weight and the abnormality detected will be taken into account in deciding the necessary treatments, or even the initiation of childbirth.