Routine antenatal checks
While you're pregnant, you'll have some routine antenatal checks to make sure both you and your baby are doing well.
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Some checks may be done at every visit, or at different times during your pregnancy. Other tests only need to be carried out once. If the tests show that there is, or may be, a problem, you'll be monitored closely and prompt action will be taken if necessary.
Height
Your height will be measured at your first visit. If you are petite, your midwife may suspect that you have a small pelvic inlet and outlet. The chances are, though, that your baby will match your particular physical build.
Weight
Women used to be weighed at every visit, but many units now only weigh you at the booking-in appointment. If you lose weight in the first trimester it's usually because of nausea and vomiting due to morning sickness and so it's nothing to worry about. Maternal weight gain used to be taken as a reliable indicator of the growth of the baby. Recent research, however, shows that external examination, blood and urinary tests, and especially ultrasound scans, are much more accurate in measuring fetal growth. A sudden weight gain could mean you have fluid retention, a sign of pre-eclampsia.
Legs and hands
In the third trimester your legs will be checked for varicose veins, and your ankles and hands will be examined for signs of swellng and puffiness (oedema). A little swelling in the final weeks of pregnancy is normal, particularly in the evening, but excessive puffiness may give an early warning of pre-eclampsia.
Breasts
Your breasts will be checked for lumps and the condition of your nipples at your first visit. They won't usually be checked again but if you're worried about anything, ask your midwife.
Urine
When you go for your first antenatal visit you'll be asked for a sample of midstream urine to test for any underlying bladder or kidney infection. To collect a midstream sample, you'll be given a sterile pad to clean your vulva and a sterile container. You pass the first few drops of urine into the toilet bowl and collect some midstream urine in the container. You then finish urinating into the toilet.
You'll be asked to bring a morning sample of urine with you on other visits. This will be tested for urinary infection; for sugar, to check you're not developing diabetes; and for ketones, which are the classic sign that diabetes is established and needs urgent treatment (see Pregnancy and diabetes). A rare cause of ketonuria (raised levels of ketones) is very severe vomiting in pregnancy, called hyperemesis gravidarum, which means that you must go to hospital right away. If you do have diabetes, it may disappear completely once your baby is born but come back in future pregnancies. Protein in your urine in late pregnancy may be a warning of pre-eclampsia. This will be looked into at once because of the risks of intrauterine growth restriction, premature delivery, or seizures.
Antenatal blood tests
Also at your first antenatal visit, you'll be asked for a blood sample, usually from a vein in your arm. This is used to check your basic blood group (A,B,O), and also your Rhesus (Rh) blood group (positive or negative), in case a blood transfusion becomes necessary. If you are Rh negative, you'll be tested for Rhesus antibodies later in your pregnancy as well.
Your haemoglobin level will also be checked. This is a measure of the oxygen-carrying power of your red blood cells. The normal level is between 12 and 14 grams; if yours falls below ten grams, you may be given treatment for anaemia. Iron and folic acid raise the oxygen-carrying power of your blood, so it's essential to eat a healthy diet with plenty of vitamins and minerals (see Food in Pregnancy).
The blood test will also show whether or not you've already had German measles (rubella)
- if you have, you're immune. Also, any sexually transmitted diseases, such as syphilis, will be revealed and some genetic disorders, such as sickle-cell anaemia and thalassaemia, are detectable in blood. You may also have a special screening blood test to help rule out certain types of fetal abnormality.
You can also ask to have your blood tested for toxoplasmosis. The toxoplasma is a parasite that can be picked up from cat faeces and from poorly cooked meat. Toxoplasmosis is harmless to adults, but it can cross the placenta and cause blindness, epilepsy, and developmental delay in the baby. You won't necessarily be given this test, so if you're worried - particularly if you have pets that hunt outside - ask for the test. Only about 20 per cent of women in the UK are immune to the disease.
External check
At every visit the midwife will gently feel your abdomen for the top of the uterus (fundus) to check the size of your growing baby. This gives a good idea of whether your baby is about the right size for your dates. Before ultrasound scans became routine, women were measured at intervals through pregnancy to monitor the baby's rate of progress. Now, scans at about 12 weeks and 18-20 weeks provide an accurate picture of how your baby is growing, and if there's any doubt you'll be scanned more frequently (see Ultrasound Scan). After 26-28 weeks the doctor or midwife will also feel for your baby's “poles” (head and rump) so they can assess which position your baby is lying in (see Understanding your notes).
Your blood pressure
You'll have this taken at every visit. As always it measures the pressure at which your heart is pumping blood through your body. The reading is made up of two numbers: the upper one is the systolic pressure - when the heart contracts, and “beats”, as it pushes out blood. This is measured when the arm band is tight. As the pressure is released, the lower, or diastolic, reading is made. This is the resting pressure between beats.
The statistically average blood pressure reading in pregnancy is 120 over 70, although blood pressure differs with age, and there's a range of blood pressures that are considered normal. A higher reading than normal during pregnancy may be a sign of pre-eclampsia and you'll probably be advised to go into hospital for bed rest. Constant checks are made so that changes are quickly noted.
Checking HIV and hepatitis B
Hepatitis B
All pregnant women should have a blood test for hepatitis B. Infected women can then be given treatment to prevent the disease being passed on to their baby.
HIV
Screening for HIV is now recommended and offered to all pregnant women. Treatment is available for women who test positive to lessen the risk of the disease being passed on to the baby. It's important to diagnose HIV early as this improves the likelihood of having a healthy baby.
Baby's heartbeat check
Your baby's heartbeat will be monitored at every visit from week 14. Your baby's heart beats almost twice as fast as yours (about 140 beats per minute compared with 72 beats per minute), and sounds just like a tiny galloping horse.
Pinnard stethoscope
The doctor or midwife may listen to your baby's heartbeat using a traditional ear trumpet known as a Pinnard stethoscope, although these are now rapidly falling out of use.
Sonicaid
It's more likely that a sonicaid will be used. This is a small portable instrument (about the size of a telephone). It's placed on your stomach and uses Doppler to listen to the baby's heartbeat. The sonicaid magnifies the sound of your baby's heartbeat, so you can hear it too.
Electronic monitor
There are two kinds of electronic monitor. In one type, an external monitor is strapped around your abdomen and sensors record the baby's heartbeat. The other, an internal monitor, has a tiny electrode that is clipped to the baby's scalp and records the heartbeat more accurately. This can only be used once your membranes are ruptured during labour. The latest monitors use radio waves so you can walk around while being monitored.
Posted 16.11.2010
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