Later Antenatal Visits

Subsequent visits to the antenatal clinic are for checking progress and for the prevention and early treatment of any complications of pregnancy. At each visit the mother-to-be will be asked how she is feeling and about any problems such as nausea, constipation and sleeplessness. Advice will be given and, if necessary, medication prescribed. The size of the uterus will be noted, and the baby’s size and position determined by abdominal palpation. Also, from about 20 weeks the baby’s heart will be listened to using a foetal stethoscope. It can be heard earlier using an ultrasonic detector. From 36 weeks the doctor will particularly want to know the baby’s position and an ultrasonic scan may be made. Around this time the baby will assume a position which is not likely to change again. More specifically, this is when the head usually becomes engaged, that is, the widest diameter of the head enters the rim of the pelvis.

The woman will be weighed at every visit but ideally she should also be able to weigh herself at home to obtain more detailed information. Often the weight will fall during the first three months but between 12 and 36 weeks she should expect a weight gain of about 800 grams per 2 weeks. Although the gain for the whole pregnancy is very variable (from 0 to more than 20 kilograms) the average is 12 kg. This increase in weight is obviously not accounted for just by the weight of the baby (3.4 kg on average); the amniotic fluid, placenta, the woman’s own increased blood circulation and heavier breasts and uterus also make a contribution.

From 36 weeks until delivery the weight will remain stable, although commonly some weight is lost after 38 weeks. If a woman puts on more weight than is recommended it will remain as body fat after delivery. A balanced diet suited to individual requirements while she is pregnant should keep the woman’s weight under control.

A sudden above-average weight gain often occurs in the condition known as pre-eclampsia, also called toxaemia of pregnancy. The first symptom is usually swelling of the ankles and feet (oedema) caused by fluid retention. The woman’s weight increases faster than average and blood pressure increases. A urine test may reveal the presence of abnormal amounts of protein in the urine. Dizziness and headaches, perhaps with visual disturbances, are a warning that pre-eclampsia may be progressing to eclampsia, in which the woman has convulsions. Because early diagnosis is important in dealing with this condition, regular weight checks are essential, particularly after 28 weeks.

Blood pressure

This will be measured at every clinic visit. One good reason for attending an antenatal clinic early in pregnancy is that blood pressure can be measured before most of the changes in the woman’s circulation and blood volume due to pregnancy have occurred. Any subsequent change can then be compared to this base level.

In general the blood pressure will show a slight fall in the second trimester. High blood pressure, as mentioned earlier, can be a significant warning sign of pre-eclampsia.

Ultrasonic scan

The woman will probably have an ultrasonic scan at about 16 weeks, which allows pregnancy to be dated very accurately. The scan will show the baby’s exact position and the position of the placenta. It is important to know that it is not lying over the cervix, a condition known as placenta praevia. It is also found out whether she is carrying more than one baby. Abnormalities such as spina bifida and hydrocephalus* can be diagnosed. An ultrasound operator can sometimes even tell the sex of the baby, although many parents choose not to be given this information, preferring to wait until the actual birth to discover the sex of their child.